Supplement and medication interactions, checked against NIH sources

Ashwagandha also withania somnifera, ksm-66, sensoril

Ashwagandha: 6 documented medication interactions in NIH ODS or NCCIH (1 moderate, 5 minor), verified 2026-10-13.

• Moderate Ashwagandha and levothyroxine: moderate interaction. Ask your prescriber before combining them and expect thyroid levels to be rechecked if you start or stop it.

  Why: Ashwagandha may raise thyroid hormone levels: NIH ODS cites trials showing higher T3 and T4 and three case reports of thyrotoxicosis.

  Applies to: thyroid hormone medicines such as levothyroxine.

  Source wording: "These findings suggest that ashwagandha might interact with thyroid hormone medications."

  NIH Office of Dietary Supplements, Ashwagandha Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Ashwagandha and anticonvulsants: minor interaction. Ask your neurologist or pharmacist before adding it.

  Why: NCCIH lists anti-seizure medicines among the drugs ashwagandha might interact with; it does not describe the size of the effect.

  Applies to: anti-seizure medicines.

  Source wording: "sedatives, anti-seizure medications (anticonvulsants), and thyroid hormone medications"

  National Center for Complementary and Integrative Health, Ashwagandha, verified 2026-10-13.

• Minor Ashwagandha and benzodiazepines/sedatives: minor interaction. Ask your pharmacist before combining it with a sedative or sleep medicine.

  Why: Ashwagandha can cause drowsiness, and NIH lists sedatives among the drugs it might interact with.

  Applies to: sedatives.

  Source wording: "sedatives, anti-seizure medications (anticonvulsants), and thyroid hormone medications"

  National Center for Complementary and Integrative Health, Ashwagandha, verified 2026-10-13.

• Minor Ashwagandha and blood pressure medicines: minor interaction. Tell your prescriber and keep checking your blood pressure if you start it.

  Why: NIH lists blood pressure medicines among the drugs ashwagandha might interact with; it does not describe the size of the effect.

  Applies to: high blood pressure medicines.

  Source wording: "There is evidence that ashwagandha might interact with some medications, including those for diabetes and high blood pressure"

  National Center for Complementary and Integrative Health, Ashwagandha, verified 2026-10-13.

• Minor Ashwagandha and diabetes medicines: minor interaction. Tell your prescriber and watch your blood sugar readings when you start or stop it.

  Why: NIH lists diabetes medicines among the drugs ashwagandha might interact with; it does not describe the size of the effect.

  Applies to: diabetes medicines.

  Source wording: "There is evidence that ashwagandha might interact with some medications, including those for diabetes and high blood pressure"

  National Center for Complementary and Integrative Health, Ashwagandha, verified 2026-10-13.

• Minor Ashwagandha and immunosuppressants: minor interaction. Do not add it without asking the doctor who prescribes your immunosuppressant.

  Why: NIH lists immunosuppressants among the drugs ashwagandha might interact with, and NCCIH does not recommend it for people with autoimmune disorders.

  Applies to: immunosuppressants.

  Source wording: "medicines that decrease the immune system response (immunosuppressants)"

  National Center for Complementary and Integrative Health, Ashwagandha, verified 2026-10-13.

No well-documented interaction in NIH ODS or NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, birth control pills, antibiotics, acid reducers, chemotherapy, lithium.

Checked against: NIH Office of Dietary Supplements, Ashwagandha Fact Sheet for Health Professionals; National Center for Complementary and Integrative Health, Ashwagandha.

Our guide: Ashwagandha: evidence, dosing and brands

Magnesium also magnesium glycinate, magnesium citrate, magnesium oxide, magnesium threonate

Magnesium: 7 documented medication interactions in NIH ODS (6 moderate, 1 minor), verified 2026-10-13.

• Moderate Magnesium and bisphosphonates: moderate interaction. Take magnesium at least 2 hours before or after the bisphosphonate.

  Why: Magnesium-rich supplements can decrease the absorption of oral bisphosphonates.

  Applies to: alendronate (Fosamax).

  Source wording: "Taking magnesium-rich supplements or medications at least 2 hours before or after oral bisphosphonates can minimize this interaction"

  NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Magnesium and loop diuretics: moderate interaction. Ask your prescriber whether your magnesium level should be checked.

  Why: Long-term loop diuretic use increases magnesium loss in urine and can lead to magnesium depletion.

  Applies to: furosemide (Lasix), bumetanide (Bumex).

  Source wording: "can increase the loss of magnesium in urine and lead to magnesium depletion"

  NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Magnesium and PPIs: moderate interaction. FDA advises checking magnesium before and periodically during long-term PPI treatment; ask your prescriber.

  Why: PPIs taken for more than about a year can cause low blood magnesium; in a quarter of FDA-reviewed cases supplements did not correct it.

  Applies to: esomeprazole (Nexium), lansoprazole (Prevacid).

  Source wording: "can cause hypomagnesemia when taken for prolonged periods (typically more than a year)"

  NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Magnesium and quinolones: moderate interaction. Take the antibiotic at least 2 hours before or 4 to 6 hours after the magnesium.

  Why: Magnesium binds quinolone antibiotics in the gut into insoluble complexes, so less antibiotic is absorbed.

  Applies to: ciprofloxacin (Cipro), levofloxacin (Levaquin).

  Source wording: "These antibiotics should be taken at least 2 hours before or 4 to 6 hours after a magnesium-containing supplement"

  NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Magnesium and tetracyclines: moderate interaction. Take the antibiotic at least 2 hours before or 4 to 6 hours after the magnesium.

  Why: Magnesium binds tetracyclines in the gut into insoluble complexes, so less antibiotic is absorbed.

  Applies to: demeclocycline (Declomycin), doxycycline (Vibramycin).

  Source wording: "These antibiotics should be taken at least 2 hours before or 4 to 6 hours after a magnesium-containing supplement"

  NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Magnesium and thiazide diuretics: moderate interaction. Ask your prescriber whether your magnesium level should be checked.

  Why: Long-term thiazide use increases magnesium loss in urine and can lead to magnesium depletion.

  Applies to: hydrochlorothiazide, ethacrynic acid (Edecrin).

  Source wording: "can increase the loss of magnesium in urine and lead to magnesium depletion"

  NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Magnesium and potassium-sparing diuretics: minor interaction. Ask your prescriber before adding magnesium, since less of it is lost in urine.

  Why: Potassium-sparing diuretics reduce how much magnesium the kidneys excrete, the opposite of loop and thiazide diuretics.

  Applies to: amiloride (Midamor), spironolactone (Aldactone).

  Source wording: "reduce magnesium excretion"

  NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, chemotherapy, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals.

Our guide: Magnesium: evidence, dosing and brands

Vitamin D also vitamin d3, cholecalciferol, vitamin d2, ergocalciferol

Vitamin D: 4 documented medication interactions in NIH ODS (3 moderate, 1 minor), verified 2026-10-13.

• Moderate Vitamin D and corticosteroids: moderate interaction. Ask whether your vitamin D status should be checked on long-term steroids.

  Why: Corticosteroids can reduce calcium absorption and impair vitamin D metabolism; deficiency was twice as common in oral steroid users in NHANES.

  Applies to: prednisone.

  Source wording: "These medications can reduce calcium absorption and impair vitamin D metabolism"

  NIH Office of Dietary Supplements, Vitamin D Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Vitamin D and statins: moderate interaction. Tell your prescriber if you take high-dose vitamin D so cholesterol results can be read in context.

  Why: High vitamin D intakes and these statins appear to compete for the same metabolizing enzyme, which might reduce statin potency.

  Applies to: atorvastatin (Lipitor), lovastatin, simvastatin (Zocor).

  Source wording: "might reduce the potency of atorvastatin (Lipitor), lovastatin (Altoprev and Mevacor), and simvastatin"

  NIH Office of Dietary Supplements, Vitamin D Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Vitamin D and thiazide diuretics: moderate interaction. Ask your clinician before combining them, especially if you are older or have kidney problems.

  Why: Thiazides lower urinary calcium loss while vitamin D raises calcium absorption, which together can push blood calcium too high.

  Applies to: Hygroton, Lozol, Microzide.

  Source wording: "might lead to hypercalcemia, especially among older adults"

  NIH Office of Dietary Supplements, Vitamin D Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Vitamin D and orlistat: minor interaction. Ask your clinician whether you need a vitamin D supplement while on orlistat.

  Why: Orlistat with a reduced-fat diet can reduce vitamin D absorption from food and supplements.

  Applies to: orlistat (Xenical, alli).

  Source wording: "can reduce the absorption of vitamin D from food and supplements"

  NIH Office of Dietary Supplements, Vitamin D Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, thyroid medicines, diabetes medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Vitamin D Fact Sheet for Health Professionals.

Our guide: Vitamin D: evidence, dosing and brands

Fish oil (omega-3) also omega-3, omega 3, epa, dha, krill oil

Fish oil (omega-3): 1 documented medication interaction in NIH ODS (1 minor), verified 2026-10-13.

• Minor Fish oil (omega-3) and warfarin: minor interaction. Keep your usual INR checks; FDA labels for omega-3 drugs advise periodic INR monitoring with anticoagulants.

  Why: High-dose fish oil has antiplatelet effects and might raise INR, though most research finds 3 to 6 g a day does not significantly change anticoagulation.

  Applies to: warfarin (Coumadin).

  Source wording: "Fish oil might prolong clotting times, as indicated by an elevated international normalized ratio (INR), when it is taken with warfarin"

  NIH Office of Dietary Supplements, Omega-3 Fatty Acids Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Omega-3 Fatty Acids Fact Sheet for Health Professionals.

Our guide: Fish oil (omega-3): evidence, dosing and brands

Probiotics also lactobacillus, bifidobacterium, saccharomyces, acidophilus

Probiotics: no harmful medication interaction documented in NIH ODS or NCCIH; 1 pairing reviewed, verified 2026-10-13.

• Reviewed, no concern Probiotics and antibiotics: reviewed, no interaction concern for most people. NCCIH considers the pair safe except for people who are very weak or immunocompromised; ask first if that applies to you.

  Why: Probiotics are often given alongside antibiotics to lower the chance of antibiotic-associated diarrhea.

  Applies to: antibiotics in general.

  Source wording: "the use of probiotics along with antibiotics appears to be safe, except for patients who are very weak or have poorly functioning immune systems"

  National Center for Complementary and Integrative Health, Probiotics: Usefulness and Safety, verified 2026-10-13.

No well-documented interaction in NIH ODS or NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, acid reducers, chemotherapy, lithium, anticonvulsants.

NIH ODS: rare serious bloodstream infections linked to probiotics mostly involved people who were severely ill or immunocompromised. NIH ODS

Checked against: NIH Office of Dietary Supplements, Probiotics Fact Sheet for Health Professionals; National Center for Complementary and Integrative Health, Probiotics: Usefulness and Safety.

Our guide: Probiotics: evidence, dosing and brands

Creatine also creatine monohydrate

Creatine: no well-documented medication interaction in NIH ODS, verified 2026-10-13. That is not the same as safe; ask your pharmacist.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Dietary Supplements for Exercise and Athletic Performance Fact Sheet for Health Professionals.

Our guide: Creatine: evidence, dosing and brands

Zinc also zinc gluconate, zinc picolinate

Zinc: 4 documented medication interactions in NIH ODS (3 moderate, 1 minor), verified 2026-10-13.

• Moderate Zinc and penicillamine: moderate interaction. Take zinc and penicillamine at least 1 hour apart.

  Why: Zinc can reduce the absorption and action of penicillamine.

  Applies to: penicillamine.

  Source wording: "people should take zinc supplements and penicillamine at least 1 hour apart"

  NIH Office of Dietary Supplements, Zinc Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Zinc and quinolones: moderate interaction. Take the antibiotic at least 2 hours before or 4 to 6 hours after the zinc.

  Why: Zinc and quinolone antibiotics bind in the gut, which can reduce absorption of both.

  Applies to: ciprofloxacin (Cipro).

  Source wording: "Taking the antibiotic at least 2 hours before or 4 to 6 hours after the zinc supplement minimizes this interaction"

  NIH Office of Dietary Supplements, Zinc Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Zinc and tetracyclines: moderate interaction. Take the antibiotic at least 2 hours before or 4 to 6 hours after the zinc.

  Why: Zinc and tetracycline antibiotics bind in the gut, which can reduce absorption of both.

  Applies to: tetracycline (Achromycin, Sumycin).

  Source wording: "Taking the antibiotic at least 2 hours before or 4 to 6 hours after the zinc supplement minimizes this interaction"

  NIH Office of Dietary Supplements, Zinc Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Zinc and thiazide diuretics: minor interaction. Ask your prescriber whether your zinc status needs attention on long-term thiazides.

  Why: Thiazide diuretics increase zinc loss in urine and lower serum zinc.

  Applies to: chlorthalidone, hydrochlorothiazide.

  Source wording: "increase zinc excretion in the urine"

  NIH Office of Dietary Supplements, Zinc Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Zinc Fact Sheet for Health Professionals.

Vitamin C also ascorbic acid

Vitamin C: 2 documented medication interactions in NIH ODS (2 minor), verified 2026-10-13.

• Minor Vitamin C and chemotherapy: minor interaction. Consult your oncologist before taking vitamin C, especially in high doses.

  Why: Whether antioxidants protect tumor cells from chemotherapy is controversial, and it is unclear oral vitamin C changes levels enough to matter.

  Applies to: cyclophosphamide, chlorambucil, carmustine, busulfan, thiotepa, doxorubicin.

  Source wording: "Individuals who are undergoing chemotherapy or radiation should consult with their oncologist prior to taking vitamin C or other antioxidant supplements"

  NIH Office of Dietary Supplements, Vitamin C Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Vitamin C and statins: minor interaction. Your clinician may monitor lipid levels if you take antioxidants with a statin.

  Why: Vitamin C with other antioxidants may blunt the HDL rise from niacin plus simvastatin; other regimens are not known to be affected.

  Applies to: simvastatin (Zocor) with niacin.

  Source wording: "may attenuate the increase in high-density lipoprotein levels that result from taking combination niacin/simvastatin (Zocor) therapy"

  NIH Office of Dietary Supplements, Vitamin C Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Vitamin C Fact Sheet for Health Professionals.

Vitamin B12 also b12, cobalamin, methylcobalamin, cyanocobalamin

Vitamin B12: 2 documented medication interactions in NIH ODS (2 moderate), verified 2026-10-13.

• Moderate Vitamin B12 and metformin: moderate interaction. Ask your clinician whether your B12 level should be checked while you take metformin.

  Why: Metformin might reduce B12 absorption and significantly lower serum B12 levels.

  Applies to: metformin.

  Source wording: "might reduce the absorption of vitamin B12 and significantly reduce serum vitamin B12 concentrations"

  NIH Office of Dietary Supplements, Vitamin B12 Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Vitamin B12 and acid reducers: moderate interaction. Ask your clinician about checking B12 on long-term acid reducers.

  Why: Acid reducers slow gastric acid release, which interferes with B12 absorption from food and can lead to deficiency.

  Applies to: omeprazole (Prilosec), lansoprazole (Prevacid), cimetidine (Tagamet).

  Source wording: "thereby lead to vitamin B12 deficiency"

  NIH Office of Dietary Supplements, Vitamin B12 Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, chemotherapy, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Vitamin B12 Fact Sheet for Health Professionals.

Our guide: Vitamin B12: evidence, dosing and brands

Lion's mane also lions mane, hericium erinaceus

Lion's mane: NIH ODS and NCCIH publish no fact sheet for lion's mane, so no medication interaction could be checked against a primary NIH source.

No NIH ODS or NCCIH fact sheet exists for Lion's mane as of 2026-10-13.

Our guide: Lion's mane: evidence, dosing and brands

Turmeric (curcumin) also curcumin

Turmeric (curcumin): no well-documented medication interaction in NCCIH, verified 2026-10-13. That is not the same as safe; ask your pharmacist.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

NCCIH: liver damage has been reported with curcumin products made more bioavailable; it names no specific drug interaction. NCCIH

Checked against: National Center for Complementary and Integrative Health, Turmeric.

Our guide: Turmeric (curcumin): evidence, dosing and brands

St. John's wort also st johns wort, hypericum

St. John's wort: 12 documented medication interactions in NCCIH (12 major), verified 2026-10-13. Most serious: anticonvulsants.

• Major St. John's wort and anticonvulsants: major interaction. Do not combine them without your neurologist.

  Why: St. John's wort can weaken some seizure medicines, including phenytoin and carbamazepine.

  Applies to: phenytoin, carbamazepine.

  Source wording: "St. John’s wort can weaken the effects of many medicines, including crucially important medicines such as"

  National Center for Complementary and Integrative Health, St. John's Wort, verified 2026-10-13.

• Major St. John's wort and birth control pills: major interaction. Do not rely on the pill alone while taking it; talk to your prescriber or pharmacist.

  Why: St. John's wort can weaken the effect of birth control pills.

  Applies to: birth control pills.

  Source wording: "St. John’s wort can weaken the effects of many medicines, including crucially important medicines such as"

  National Center for Complementary and Integrative Health, St. John's Wort, verified 2026-10-13.

• Major St. John's wort and bupropion: major interaction. Do not combine them without your prescriber.

  Why: St. John's wort can weaken the effect of some antidepressants, including bupropion.

  Applies to: bupropion.

  Source wording: "St. John’s wort can weaken the effects of many medicines, including crucially important medicines such as"

  National Center for Complementary and Integrative Health, St. John's Wort, verified 2026-10-13.

• Major St. John's wort and chemotherapy: major interaction. Do not take it during cancer treatment without your oncologist.

  Why: St. John's wort can weaken some cancer medicines, including irinotecan, imatinib and docetaxel.

  Applies to: irinotecan, imatinib, docetaxel.

  Source wording: "St. John’s wort can weaken the effects of many medicines, including crucially important medicines such as"

  National Center for Complementary and Integrative Health, St. John's Wort, verified 2026-10-13.

• Major St. John's wort and digoxin/ivabradine: major interaction. Do not combine them without your cardiologist.

  Why: St. John's wort can weaken some heart medicines, including digoxin and ivabradine.

  Applies to: digoxin, ivabradine.

  Source wording: "St. John’s wort can weaken the effects of many medicines, including crucially important medicines such as"

  National Center for Complementary and Integrative Health, St. John's Wort, verified 2026-10-13.

• Major St. John's wort and HIV medicines: major interaction. Do not combine them without your HIV care team.

  Why: St. John's wort can weaken some HIV drugs, including indinavir and nevirapine.

  Applies to: indinavir, nevirapine.

  Source wording: "St. John’s wort can weaken the effects of many medicines, including crucially important medicines such as"

  National Center for Complementary and Integrative Health, St. John's Wort, verified 2026-10-13.

• Major St. John's wort and immunosuppressants: major interaction. Do not take it with cyclosporine unless your transplant team approves.

  Why: St. John's wort can weaken cyclosporine, which prevents rejection of transplanted organs.

  Applies to: cyclosporine.

  Source wording: "St. John’s wort can weaken the effects of many medicines, including crucially important medicines such as"

  National Center for Complementary and Integrative Health, St. John's Wort, verified 2026-10-13.

• Major St. John's wort and MAOIs: major interaction. Do not combine them without your prescriber.

  Why: St. John's wort with drugs that affect serotonin may cause serotonin-related side effects, which can be serious.

  Applies to: antidepressants that affect serotonin.

  Source wording: "may lead to increased serotonin-related side effects, which can be serious"

  National Center for Complementary and Integrative Health, St. John's Wort, verified 2026-10-13.

• Major St. John's wort and SSRIs/SNRIs: major interaction. Do not combine them without your prescriber; ask your pharmacist before taking any St. John's wort product.

  Why: St. John's wort with drugs that affect serotonin may cause serotonin-related side effects, which can be serious.

  Applies to: antidepressants that affect serotonin.

  Source wording: "may lead to increased serotonin-related side effects, which can be serious"

  National Center for Complementary and Integrative Health, St. John's Wort, verified 2026-10-13.

• Major St. John's wort and statins: major interaction. Do not combine them without your prescriber.

  Why: St. John's wort can weaken certain statins, including simvastatin.

  Applies to: simvastatin.

  Source wording: "St. John’s wort can weaken the effects of many medicines, including crucially important medicines such as"

  National Center for Complementary and Integrative Health, St. John's Wort, verified 2026-10-13.

• Major St. John's wort and tricyclics: major interaction. Do not combine them without your prescriber.

  Why: St. John's wort can weaken the effect of some antidepressants, including amitriptyline.

  Applies to: amitriptyline.

  Source wording: "St. John’s wort can weaken the effects of many medicines, including crucially important medicines such as"

  National Center for Complementary and Integrative Health, St. John's Wort, verified 2026-10-13.

• Major St. John's wort and warfarin: major interaction. Do not combine them without your prescriber.

  Why: St. John's wort can weaken the anticoagulant warfarin.

  Applies to: warfarin.

  Source wording: "St. John’s wort can weaken the effects of many medicines, including crucially important medicines such as"

  National Center for Complementary and Integrative Health, St. John's Wort, verified 2026-10-13.

No well-documented interaction in NCCIH for: antiplatelets, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, antibiotics, acid reducers, lithium.

Checked against: National Center for Complementary and Integrative Health, St. John's Wort.

Ginkgo also ginkgo biloba

Ginkgo: 1 documented medication interaction in NCCIH (1 moderate), verified 2026-10-13.

• Moderate Ginkgo and anticoagulants: moderate interaction. Ask your prescriber before combining them.

  Why: Ginkgo may increase the risk of bleeding in people taking anticoagulants.

  Applies to: warfarin.

  Source wording: "Ginkgo may increase the risk of bleeding in people who are taking anticoagulant drugs, such as warfarin."

  National Center for Complementary and Integrative Health, Ginkgo, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Ginkgo.

Melatonin

Melatonin: 1 documented medication interaction in NCCIH (1 moderate), verified 2026-10-13.

• Moderate Melatonin and anticoagulants: moderate interaction. Use melatonin with a blood thinner only under medical supervision.

  Why: NCCIH flags blood thinners as a combination that needs medical supervision; it does not describe the mechanism.

  Applies to: blood thinners.

  Source wording: "people with epilepsy and those taking blood thinner medications need to be under medical supervision when taking melatonin supplements"

  National Center for Complementary and Integrative Health, Melatonin: What You Need To Know, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

NCCIH: people with epilepsy also need medical supervision when taking melatonin. NCCIH

Checked against: National Center for Complementary and Integrative Health, Melatonin: What You Need To Know.

Berberine

Berberine: NIH ODS and NCCIH publish no fact sheet for berberine, so no medication interaction could be checked against a primary NIH source.

NIH publishes no berberine fact sheet. NCCIH documents a metformin interaction for goldenseal, an herb that contains berberine (see Goldenseal below); that finding is for goldenseal extract, not purified berberine. NCCIH

No NIH ODS or NCCIH fact sheet exists for Berberine as of 2026-10-13.

Our guide: Berberine: evidence, dosing and brands

Boswellia also indian frankincense, boswellia serrata

Boswellia: no well-documented medication interaction in NCCIH, verified 2026-10-13. That is not the same as safe; ask your pharmacist.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

NCCIH: if you take asthma medicine, talk with your provider before starting a supplement. It names no specific drug interaction. NCCIH

Checked against: National Center for Complementary and Integrative Health, Boswellia.

Our guide: Boswellia: evidence, dosing and brands

Iron also ferrous sulfate, ferrous gluconate, iron bisglycinate

Iron: 3 documented medication interactions in NIH ODS (2 moderate, 1 minor), verified 2026-10-13.

• Moderate Iron and levodopa: moderate interaction. Take iron at a different time of day than levodopa and ask your pharmacist about timing.

  Why: Iron may bind levodopa and reduce how much reaches the body; US levodopa labels carry this warning.

  Applies to: levodopa (Sinemet, Stalevo).

  Source wording: "the labels for levodopa warn that iron-containing dietary supplements might reduce the amount of levodopa available to the body"

  NIH Office of Dietary Supplements, Iron Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Iron and levothyroxine: moderate interaction. Do not take levothyroxine within 4 hours of an iron supplement.

  Why: Taking iron and levothyroxine together can significantly reduce levothyroxine absorption.

  Applies to: levothyroxine (Synthroid, Levoxyl, Unithroid, Tirosint).

  Source wording: "advise against administering levothyroxine within 4 hours of iron supplements"

  NIH Office of Dietary Supplements, Iron Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Iron and PPIs: minor interaction. If you are iron deficient and on a PPI, tell your clinician, since response to iron can be weaker.

  Why: PPIs reduce stomach acid, which can reduce iron absorption; people with normal iron stores are not depleted.

  Applies to: lansoprazole (Prevacid), omeprazole (Prilosec).

  Source wording: "patients with iron deficiency taking proton pump inhibitors can have suboptimal responses to iron supplementation"

  NIH Office of Dietary Supplements, Iron Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, chemotherapy, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Iron Fact Sheet for Health Professionals.

Calcium also calcium carbonate, calcium citrate

Calcium: 4 documented medication interactions in NIH ODS (4 moderate), verified 2026-10-13.

• Moderate Calcium and HIV medicines: moderate interaction. Take dolutegravir 2 hours before or 6 hours after calcium, as the FDA label advises.

  Why: Calcium can substantially lower dolutegravir blood levels, apparently by binding it.

  Applies to: dolutegravir (Tivicay, Dovato).

  Source wording: "advise patients to take dolutegravir 2 hours before or 6 hours after taking calcium supplements"

  NIH Office of Dietary Supplements, Calcium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Calcium and lithium: moderate interaction. Ask your prescriber before taking calcium supplements with lithium.

  Why: Long-term lithium can cause high blood calcium, and calcium supplements could add to that risk.

  Applies to: lithium (Eskalith, Lithobid).

  Source wording: "use of both lithium and calcium supplements could increase this risk"

  NIH Office of Dietary Supplements, Calcium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Calcium and quinolones: moderate interaction. Take the antibiotic 2 hours before or 2 hours after calcium.

  Why: Taking calcium at the same time can reduce absorption of quinolone antibiotics.

  Applies to: ciprofloxacin (Cipro), gemifloxacin (Factive), moxifloxacin (Avelox).

  Source wording: "Taking the antibiotic 2 hours before or 2 hours after calcium supplements prevents this effect"

  NIH Office of Dietary Supplements, Calcium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Calcium and levothyroxine: moderate interaction. Do not take levothyroxine within 4 hours of calcium carbonate.

  Why: Calcium carbonate can interfere with levothyroxine absorption.

  Applies to: levothyroxine (Synthroid, Levoxyl).

  Source wording: "avoid taking levothyroxine within 4 hours of taking the supplement"

  NIH Office of Dietary Supplements, Calcium Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, acid reducers, chemotherapy, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Calcium Fact Sheet for Health Professionals.

Vitamin K also vitamin k1, vitamin k2, phylloquinone, menaquinone, mk-7

Vitamin K: 4 documented medication interactions in NIH ODS (1 major, 3 minor), verified 2026-10-13. Most serious: warfarin.

• Major Vitamin K and warfarin: major interaction. Do not start or stop vitamin K supplements on warfarin without your prescriber; keep your vitamin K intake consistent.

  Why: Warfarin works by blocking vitamin K, so a sudden change in vitamin K intake can raise or lower its effect.

  Applies to: warfarin (Coumadin), phenprocoumon, acenocoumarol.

  Source wording: "Vitamin K can have a serious and potentially dangerous interaction with anticoagulants such as warfarin"

  NIH Office of Dietary Supplements, Vitamin K Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Vitamin K and antibiotics: minor interaction. Supplements are usually not needed unless antibiotics run for several weeks with a poor vitamin K intake.

  Why: Antibiotics can kill vitamin K-producing gut bacteria; cephalosporins may also block vitamin K action.

  Applies to: cephalosporins such as cefoperazone.

  Source wording: "Vitamin K supplements are usually not needed unless antibiotic use is prolonged (beyond several weeks) and accompanied by poor vitamin K intake"

  NIH Office of Dietary Supplements, Vitamin K Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Vitamin K and bile acid sequestrants: minor interaction. Ask whether vitamin K status should be monitored if you take these for many years.

  Why: Bile acid sequestrants can reduce absorption of vitamin K and other fat-soluble vitamins.

  Applies to: cholestyramine (Questran), colestipol (Colestid).

  Source wording: "although the clinical significance of this effect is not clear"

  NIH Office of Dietary Supplements, Vitamin K Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Vitamin K and orlistat: minor interaction. Clinicians usually recommend a multivitamin with vitamin K while on orlistat; ask yours.

  Why: Orlistat reduces fat absorption and with it the absorption of fat-soluble vitamins such as vitamin K.

  Applies to: orlistat (Alli, Xenical).

  Source wording: "it can also reduce the absorption of fat-soluble vitamins, such as vitamin K"

  NIH Office of Dietary Supplements, Vitamin K Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Vitamin K Fact Sheet for Health Professionals.

CoQ10 (coenzyme Q10) also coenzyme q10, ubiquinol, ubiquinone

CoQ10 (coenzyme Q10): 3 documented medication interactions in NCCIH (3 minor), verified 2026-10-13.

• Minor CoQ10 (coenzyme Q10) and chemotherapy: minor interaction. Ask your oncologist before taking CoQ10 during treatment.

  Why: NCCIH states CoQ10 may not be compatible with some types of cancer treatment.

  Applies to: some types of cancer treatment.

  Source wording: "CoQ10 may interact with the anticoagulant (blood thinner) warfarin and the diabetes drug insulin, and it may not be compatible with some types of cancer treatment."

  National Center for Complementary and Integrative Health, Coenzyme Q10, verified 2026-10-13.

• Minor CoQ10 (coenzyme Q10) and insulin: minor interaction. Ask your prescriber before starting CoQ10 with insulin.

  Why: NCCIH states CoQ10 may interact with insulin without describing the effect.

  Applies to: insulin.

  Source wording: "CoQ10 may interact with the anticoagulant (blood thinner) warfarin and the diabetes drug insulin, and it may not be compatible with some types of cancer treatment."

  National Center for Complementary and Integrative Health, Coenzyme Q10, verified 2026-10-13.

• Minor CoQ10 (coenzyme Q10) and warfarin: minor interaction. Ask your prescriber before starting CoQ10 on warfarin.

  Why: NCCIH states CoQ10 may interact with warfarin without describing the effect.

  Applies to: warfarin.

  Source wording: "CoQ10 may interact with the anticoagulant (blood thinner) warfarin and the diabetes drug insulin, and it may not be compatible with some types of cancer treatment."

  National Center for Complementary and Integrative Health, Coenzyme Q10, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, antiplatelets, statins, thyroid medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Coenzyme Q10.

Rhodiola also rhodiola rosea, golden root

Rhodiola: 1 documented medication interaction in NCCIH (1 minor), verified 2026-10-13.

• Minor Rhodiola and ARBs: minor interaction. Ask your prescriber before taking rhodiola with losartan.

  Why: Interactions between rhodiola and losartan have been reported; the source does not describe them.

  Applies to: losartan.

  Source wording: "Interactions between rhodiola and losartan (a drug used for high blood pressure) have been reported."

  National Center for Complementary and Integrative Health, Rhodiola, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Rhodiola.

Our guide: Rhodiola: evidence, dosing and brands

Valerian also valerian root

Valerian: 1 documented medication interaction in NCCIH (1 major), verified 2026-10-13. Most serious: benzodiazepines/sedatives.

• Major Valerian and benzodiazepines/sedatives: major interaction. NCCIH says not to take valerian with alcohol or sedatives.

  Why: Valerian might have a sleep-inducing effect that adds to sedatives.

  Applies to: sedatives.

  Source wording: "it should not be taken along with alcohol or sedatives"

  National Center for Complementary and Integrative Health, Valerian, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Valerian.

Kava also kava kava

Kava: 1 documented medication interaction in NCCIH (1 major), verified 2026-10-13. Most serious: benzodiazepines/sedatives.

• Major Kava and benzodiazepines/sedatives: major interaction. NCCIH says not to use kava with benzodiazepines, other sedatives or alcohol.

  Why: Kava adds to the effect of other sedating substances.

  Applies to: benzodiazepines.

  Source wording: "Kava should not be used together with other substances that have sedative effects, such as benzodiazepines or alcohol."

  National Center for Complementary and Integrative Health, Kava, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Kava.

Garlic also garlic extract, aged garlic

Garlic: 2 documented medication interactions in NCCIH (2 moderate), verified 2026-10-13.

• Moderate Garlic and anticoagulants: moderate interaction. Tell your prescriber you take garlic supplements, especially before surgery.

  Why: Garlic supplements may increase the risk of bleeding, adding to drugs that affect bleeding.

  Applies to: anticoagulants.

  Source wording: "if you take medicines, such as anticoagulants or aspirin, that may also affect bleeding"

  National Center for Complementary and Integrative Health, Garlic, verified 2026-10-13.

• Moderate Garlic and antiplatelets: moderate interaction. Tell your prescriber you take garlic supplements, especially before surgery.

  Why: Garlic supplements may increase the risk of bleeding, adding to drugs that affect bleeding.

  Applies to: aspirin.

  Source wording: "if you take medicines, such as anticoagulants or aspirin, that may also affect bleeding"

  National Center for Complementary and Integrative Health, Garlic, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Garlic.

Ginseng (Asian) also panax ginseng, korean ginseng, red ginseng

Ginseng (Asian): 1 documented medication interaction in NCCIH or NIH ODS (1 moderate), verified 2026-10-13.

• Moderate Ginseng (Asian) and warfarin: moderate interaction. Talk to your prescriber before combining them.

  Why: Ginseng can reduce the anticoagulant effect of warfarin.

  Applies to: warfarin (Coumadin, Jantoven).

  Source wording: "Ginseng can reduce the anticoagulant effects of the blood thinner warfarin (Coumadin or Jantoven)"

  NIH Office of Dietary Supplements, Dietary Supplements for Exercise and Athletic Performance Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NCCIH or NIH ODS for: SSRIs/SNRIs, MAOIs, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

NCCIH: Asian ginseng might lower blood sugar, so people with diabetes should consult a provider first. NCCIH

Checked against: National Center for Complementary and Integrative Health, Asian Ginseng; NIH Office of Dietary Supplements, Dietary Supplements for Exercise and Athletic Performance Fact Sheet for Health Professionals.

Green tea extract also green tea, egcg, camellia sinensis

Green tea extract: 4 documented medication interactions in NCCIH or NIH ODS (2 moderate, 2 minor), verified 2026-10-13.

• Moderate Green tea extract and beta-blockers: moderate interaction. Ask your prescriber before taking green tea supplements with nadolol.

  Why: High-dose green tea has been shown to lower blood levels, and so the effectiveness, of nadolol.

  Applies to: nadolol (Corgard).

  Source wording: "Green tea at high doses has been shown to reduce blood levels and, therefore, the effectiveness of the drug nadolol"

  National Center for Complementary and Integrative Health, Green Tea, verified 2026-10-13.

• Moderate Green tea extract and statins: moderate interaction. Ask your prescriber before taking green tea extract with atorvastatin.

  Why: Green tea extract can lower blood levels of atorvastatin.

  Applies to: atorvastatin (Lipitor).

  Source wording: "Green tea extract can reduce blood levels of the cholesterol-lowering drug atorvastatin."

  National Center for Complementary and Integrative Health, Green Tea, verified 2026-10-13.

• Minor Green tea extract and chemotherapy: minor interaction. Ask your oncologist before taking green tea extract during treatment.

  Why: NIH ODS states green tea could interact with chemotherapy drugs without describing the effect.

  Applies to: chemotherapy drugs.

  Source wording: "Green tea could interact with chemotherapy drugs"

  NIH Office of Dietary Supplements, Dietary Supplements for Weight Loss Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Green tea extract and raloxifene: minor interaction. Ask your prescriber before taking green tea supplements with raloxifene.

  Why: An NCCIH-funded study showed an interaction between green tea and raloxifene; the size of the effect is not stated.

  Applies to: raloxifene (Evista).

  Source wording: "showed an interaction between green tea and the drug raloxifene"

  National Center for Complementary and Integrative Health, Green Tea, verified 2026-10-13.

No well-documented interaction in NCCIH or NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, thyroid medicines, diabetes medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Green Tea; NIH Office of Dietary Supplements, Dietary Supplements for Weight Loss Fact Sheet for Health Professionals.

5-HTP also 5-hydroxytryptophan

5-HTP: NIH ODS and NCCIH publish no fact sheet for 5-HTP, so no medication interaction could be checked against a primary NIH source.

No NIH ODS or NCCIH fact sheet exists for 5-HTP as of 2026-10-13.

Folate (folic acid) also folic acid, methylfolate, l-methylfolate

Folate (folic acid): 3 documented medication interactions in NIH ODS (3 moderate), verified 2026-10-13.

• Moderate Folate (folic acid) and anticonvulsants: moderate interaction. Check with your prescriber before taking folate with an antiepileptic drug.

  Why: These drugs can lower folate levels, and folate supplements might lower blood levels of the drugs.

  Applies to: phenytoin (Dilantin), carbamazepine (Tegretol), valproate (Depacon).

  Source wording: "folate supplements might reduce serum levels of these medications"

  NIH Office of Dietary Supplements, Folate Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Folate (folic acid) and methotrexate: moderate interaction. If you take methotrexate for cancer, consult your oncologist before taking folate.

  Why: Methotrexate is a folate antagonist, so folate could interfere with its anticancer effect; at low doses for arthritis or psoriasis folate may reduce side effects.

  Applies to: methotrexate (Rheumatrex, Trexall).

  Source wording: "Patients taking methotrexate for cancer should consult their oncologist before taking folate supplements"

  NIH Office of Dietary Supplements, Folate Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Folate (folic acid) and sulfasalazine: moderate interaction. Ask your prescriber whether you need more dietary folate, a supplement, or both.

  Why: Sulfasalazine blocks folate absorption in the gut and can cause folate deficiency.

  Applies to: sulfasalazine (Azulfidine).

  Source wording: "It inhibits the intestinal absorption of folate and can cause folate deficiency"

  NIH Office of Dietary Supplements, Folate Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium.

Checked against: NIH Office of Dietary Supplements, Folate Fact Sheet for Health Professionals.

Selenium

Selenium: 1 documented medication interaction in NIH ODS (1 minor), verified 2026-10-13.

• Minor Selenium and chemotherapy: minor interaction. Ask your oncologist before adding selenium during cisplatin treatment.

  Why: Cisplatin can lower selenium levels; whether that matters clinically is not known.

  Applies to: cisplatin.

  Source wording: "whether these reductions have a clinically significant impact is not known"

  NIH Office of Dietary Supplements, Selenium Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Selenium Fact Sheet for Health Professionals.

Vitamin A also retinol, beta-carotene

Vitamin A: 2 documented medication interactions in NIH ODS (1 moderate, 1 minor), verified 2026-10-13.

• Moderate Vitamin A and oral retinoids: moderate interaction. Do not add vitamin A supplements to an oral retinoid without your prescriber.

  Why: Oral retinoids are derived from vitamin A, so adding vitamin A supplements raises the risk of vitamin A toxicity.

  Applies to: acitretin (Soriatane), bexarotene (Targretin).

  Source wording: "Retinoids can increase the risk of hypervitaminosis A when taken in combination with vitamin A supplements"

  NIH Office of Dietary Supplements, Vitamin A Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Vitamin A and orlistat: minor interaction. The manufacturers recommend a multivitamin with vitamin A and beta-carotene; ask your clinician about timing.

  Why: Orlistat can decrease absorption of vitamin A and beta-carotene.

  Applies to: orlistat (Alli, Xenical).

  Source wording: "can decrease the absorption of vitamin A, other fat-soluble vitamins, and beta-carotene"

  NIH Office of Dietary Supplements, Vitamin A Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Vitamin A Fact Sheet for Health Professionals.

Vitamin E also tocopherol

Vitamin E: 4 documented medication interactions in NIH ODS (3 moderate, 1 minor), verified 2026-10-13.

• Moderate Vitamin E and anticoagulants: moderate interaction. Ask your prescriber before taking high-dose vitamin E with a blood thinner.

  Why: Vitamin E can inhibit platelets and oppose vitamin K clotting factors; large doses (probably over 400 IU a day) can raise bleeding risk.

  Applies to: warfarin (Coumadin).

  Source wording: "can increase the risk of bleeding"

  NIH Office of Dietary Supplements, Vitamin E Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Vitamin E and antiplatelets: moderate interaction. Ask your prescriber before taking high-dose vitamin E with an antiplatelet drug.

  Why: Vitamin E can inhibit platelet aggregation, so large doses with antiplatelet drugs can raise bleeding risk.

  Applies to: antiplatelet medicines.

  Source wording: "taking large doses with anticoagulant or antiplatelet medications, such as warfarin (Coumadin), can increase the risk of bleeding"

  NIH Office of Dietary Supplements, Vitamin E Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Vitamin E and chemotherapy: moderate interaction. Oncologists generally advise against antioxidant supplements during treatment; ask yours.

  Why: Antioxidants might reduce how well chemotherapy and radiation damage cancer cells; a systematic review has questioned this.

  Applies to: chemotherapy and radiotherapy.

  Source wording: "Oncologists generally advise against the use of antioxidant supplements during cancer chemotherapy or radiotherapy"

  NIH Office of Dietary Supplements, Vitamin E Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Vitamin E and statins: minor interaction. Tell your clinician if you take antioxidant supplements with this combination.

  Why: An antioxidant mix including vitamin E blunted the HDL rise in people on simvastatin plus niacin.

  Applies to: simvastatin (Zocor) with niacin.

  Source wording: "blunted the rise in high-density lipoprotein (HDL) cholesterol levels"

  NIH Office of Dietary Supplements, Vitamin E Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Vitamin E Fact Sheet for Health Professionals.

Vitamin B6 also b6, pyridoxine, p5p

Vitamin B6: 3 documented medication interactions in NIH ODS (2 moderate, 1 minor), verified 2026-10-13.

• Moderate Vitamin B6 and anticonvulsants: moderate interaction. Tell your neurologist before taking high-dose B6 with an antiepileptic drug.

  Why: High-dose pyridoxine (200 mg a day) can lower phenytoin and phenobarbital levels, and these drugs also lower B6.

  Applies to: phenytoin (Dilantin), phenobarbital, valproic acid, carbamazepine.

  Source wording: "can reduce serum concentrations of phenytoin and phenobarbital"

  NIH Office of Dietary Supplements, Vitamin B6 Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Vitamin B6 and tuberculosis drugs: moderate interaction. B6 supplements can help prevent these effects; take them as your prescriber directs.

  Why: Cycloserine increases B6 loss in urine, which might worsen its seizure and nerve side effects.

  Applies to: cycloserine (Seromycin).

  Source wording: "Pyridoxine supplements can help prevent these adverse effects."

  NIH Office of Dietary Supplements, Vitamin B6 Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Vitamin B6 and theophylline: minor interaction. Ask your prescriber whether your B6 status matters on theophylline.

  Why: People on theophylline often have low B6 (PLP) levels, which could contribute to its nervous system side effects.

  Applies to: theophylline.

  Source wording: "Patients treated with theophylline often have low plasma PLP concentrations"

  NIH Office of Dietary Supplements, Vitamin B6 Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, acid reducers, chemotherapy, lithium.

Checked against: NIH Office of Dietary Supplements, Vitamin B6 Fact Sheet for Health Professionals.

Niacin (vitamin B3) also vitamin b3, nicotinic acid, niacinamide

Niacin (vitamin B3): 2 documented medication interactions in NIH ODS (2 moderate), verified 2026-10-13.

• Moderate Niacin (vitamin B3) and diabetes medicines: moderate interaction. Have blood glucose monitored if you take high-dose niacin with diabetes medicine; doses may need adjusting.

  Why: Large doses of nicotinic acid (1.5 g a day or more) can raise blood glucose by worsening insulin resistance.

  Applies to: any antidiabetes medicine.

  Source wording: "People who take any antidiabetes medications should have their blood glucose levels monitored if they take high-dose nicotinic acid supplements concomitantly"

  NIH Office of Dietary Supplements, Niacin Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Niacin (vitamin B3) and tuberculosis drugs: moderate interaction. Ask your prescriber about extra niacin during TB treatment.

  Why: These TB drugs interfere with the body making niacin, and pellagra can occur.

  Applies to: isoniazid, pyrazinamide (Rifater).

  Source wording: "it can be prevented with increased intakes of niacin"

  NIH Office of Dietary Supplements, Niacin Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Niacin Fact Sheet for Health Professionals.

Potassium also potassium chloride, potassium citrate

Potassium: 5 documented medication interactions in NIH ODS (5 moderate), verified 2026-10-13.

• Moderate Potassium and ACE inhibitors: moderate interaction. Do not take potassium supplements with an ACE inhibitor unless your prescriber says so; potassium should be monitored.

  Why: ACE inhibitors reduce potassium loss in urine, so extra potassium can lead to high blood potassium.

  Applies to: benazepril (Lotensin).

  Source wording: "These medications reduce urinary potassium excretion, which can lead to hyperkalemia."

  NIH Office of Dietary Supplements, Potassium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Potassium and ARBs: moderate interaction. Do not take potassium supplements with an ARB unless your prescriber says so; potassium should be monitored.

  Why: ARBs reduce potassium loss in urine, so extra potassium can lead to high blood potassium.

  Applies to: losartan (Cozaar).

  Source wording: "These medications reduce urinary potassium excretion, which can lead to hyperkalemia."

  NIH Office of Dietary Supplements, Potassium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Potassium and loop diuretics: moderate interaction. Potassium is monitored on these drugs and supplements are started only if warranted; follow your prescriber.

  Why: Loop diuretics increase potassium loss in urine and can cause low blood potassium.

  Applies to: furosemide (Lasix), bumetanide (Bumex).

  Source wording: "increases urinary potassium excretion and can lead to hypokalemia"

  NIH Office of Dietary Supplements, Potassium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Potassium and potassium-sparing diuretics: moderate interaction. Do not add potassium supplements unless your prescriber says so; potassium should be monitored.

  Why: These diuretics hold potassium in the body and can cause high blood potassium on their own.

  Applies to: amiloride (Midamor), spironolactone (Aldactone).

  Source wording: "reduce the excretion of potassium in the urine and can cause hyperkalemia"

  NIH Office of Dietary Supplements, Potassium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Potassium and thiazide diuretics: moderate interaction. Potassium is monitored on these drugs and supplements are started only if warranted; follow your prescriber.

  Why: Thiazide diuretics increase potassium loss in urine and can cause low blood potassium.

  Applies to: chlorothiazide (Diuril), metolazone (Zaroxolyn).

  Source wording: "increases urinary potassium excretion and can lead to hypokalemia"

  NIH Office of Dietary Supplements, Potassium Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Potassium Fact Sheet for Health Professionals.

Chromium also chromium picolinate

Chromium: 3 documented medication interactions in NIH ODS (3 moderate), verified 2026-10-13.

• Moderate Chromium and diabetes medicines: moderate interaction. Ask your prescriber first and watch for low blood sugar.

  Why: Chromium might lower blood glucose, adding to the effect of diabetes medicines.

  Applies to: metformin and other antidiabetes medicines.

  Source wording: "might have an additive effect with metformin or other antidiabetes medications and thus might increase the risk of hypoglycemia"

  NIH Office of Dietary Supplements, Chromium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Chromium and insulin: moderate interaction. Ask your prescriber first and watch for low blood sugar.

  Why: Chromium might increase insulin sensitivity, adding to the glucose-lowering effect of insulin.

  Applies to: insulin.

  Source wording: "Taking chromium concomitantly with insulin could increase the risk of hypoglycemia"

  NIH Office of Dietary Supplements, Chromium Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Chromium and levothyroxine: moderate interaction. Do not take them at the same time; ask your pharmacist how far apart to space them.

  Why: In a small study, chromium picolinate taken at the same time as levothyroxine decreased its absorption.

  Applies to: levothyroxine.

  Source wording: "taking chromium picolinate supplements at the same time as levothyroxine (used to treat hypothyroidism) decreases levothyroxine absorption over 6 hours"

  NIH Office of Dietary Supplements, Chromium Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Chromium Fact Sheet for Health Professionals.

Iodine (potassium iodide) also potassium iodide, kelp

Iodine (potassium iodide): 3 documented medication interactions in NIH ODS (3 moderate), verified 2026-10-13.

• Moderate Iodine (potassium iodide) and ACE inhibitors: moderate interaction. Ask your prescriber before taking potassium iodide with an ACE inhibitor.

  Why: Potassium iodide adds potassium while ACE inhibitors reduce its loss, raising the risk of high blood potassium.

  Applies to: benazepril (Lotensin), lisinopril (Prinivil, Zestril), fosinopril (Monopril).

  Source wording: "Taking potassium iodide with ACE inhibitors can increase the risk of hyperkalemia"

  NIH Office of Dietary Supplements, Iodine Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Iodine (potassium iodide) and antithyroid drugs: moderate interaction. Do not take high-dose iodine with an antithyroid drug unless your prescriber says so.

  Why: High-dose iodine adds to the effect of antithyroid drugs and could cause hypothyroidism.

  Applies to: methimazole (Tapazole).

  Source wording: "Taking high doses of iodine with antithyroid medications can have an additive effect"

  NIH Office of Dietary Supplements, Iodine Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Iodine (potassium iodide) and potassium-sparing diuretics: moderate interaction. Ask your prescriber before taking potassium iodide with a potassium-sparing diuretic.

  Why: Potassium iodide adds potassium while these diuretics hold it in, raising the risk of high blood potassium.

  Applies to: spironolactone (Aldactone), amiloride (Midamor).

  Source wording: "Taking potassium iodide with potassium-sparing diuretics, such as spironolactone (Aldactone) and amiloride (Midamor), can increase the risk of hyperkalemia"

  NIH Office of Dietary Supplements, Iodine Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, diabetes medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Iodine Fact Sheet for Health Professionals.

Thiamin (vitamin B1) also thiamine, vitamin b1, benfotiamine

Thiamin (vitamin B1): 2 documented medication interactions in NIH ODS (1 moderate, 1 minor), verified 2026-10-13.

• Moderate Thiamin (vitamin B1) and chemotherapy: moderate interaction. Ask your oncologist whether thiamin is appropriate during fluorouracil treatment.

  Why: Fluorouracil might speed thiamin breakdown; cases of beriberi and Wernicke encephalopathy have been reported.

  Applies to: fluorouracil (5-FU, Adrucil).

  Source wording: "The published literature includes several cases of beriberi or Wernicke’s encephalopathy resulting from treatment with this drug"

  NIH Office of Dietary Supplements, Thiamin Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor Thiamin (vitamin B1) and loop diuretics: minor interaction. Ask your clinician; whether thiamin supplements prevent this has not been established.

  Why: Furosemide increases thiamin loss in urine, possibly to deficient levels.

  Applies to: furosemide (Lasix).

  Source wording: "Research has linked the use of furosemide to decreases in thiamin concentrations"

  NIH Office of Dietary Supplements, Thiamin Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, lithium, anticonvulsants.

Checked against: NIH Office of Dietary Supplements, Thiamin Fact Sheet for Health Professionals.

Biotin also vitamin b7

Biotin: 1 documented medication interaction in NIH ODS (1 moderate), verified 2026-10-13.

• Moderate Biotin and anticonvulsants: moderate interaction. Ask your clinician whether your biotin status needs attention on long-term anticonvulsants.

  Why: Long-term anticonvulsant use was linked to significantly lower biotin levels, likely from faster biotin breakdown.

  Applies to: carbamazepine, primidone, phenytoin, phenobarbital.

  Source wording: "anticonvulsant treatment for at least 1 year was associated with significantly lower serum biotin levels"

  NIH Office of Dietary Supplements, Biotin Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium.

Checked against: NIH Office of Dietary Supplements, Biotin Fact Sheet for Health Professionals.

L-carnitine also carnitine, acetyl-l-carnitine, alcar

L-carnitine: 2 documented medication interactions in NIH ODS (2 minor), verified 2026-10-13.

• Minor L-carnitine and antibiotics: minor interaction. No action is described by the source; mention it to your prescriber if you take these antibiotics long term.

  Why: Long-term use of these antibiotics can deplete carnitine, but no illness from it has been described.

  Applies to: pivalate-conjugated antibiotics such as pivampicillin.

  Source wording: "no cases of illness due to carnitine deficiency in this population have been described"

  NIH Office of Dietary Supplements, Carnitine Fact Sheet for Health Professionals, verified 2026-10-13.

• Minor L-carnitine and anticonvulsants: minor interaction. Ask your neurologist whether carnitine is relevant to your treatment.

  Why: These anticonvulsants lower blood carnitine levels.

  Applies to: valproic acid, phenobarbital, phenytoin, carbamazepine.

  Source wording: "Treatment with the anticonvulsants valproic acid, phenobarbital, phenytoin, and carbamazepine reduces blood levels of carnitine"

  NIH Office of Dietary Supplements, Carnitine Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, acid reducers, chemotherapy, lithium.

Checked against: NIH Office of Dietary Supplements, Carnitine Fact Sheet for Health Professionals.

Goldenseal also hydrastis

Goldenseal: 1 documented medication interaction in NCCIH (1 moderate), verified 2026-10-13.

• Moderate Goldenseal and metformin: moderate interaction. Ask your prescriber before using goldenseal; it may hinder glucose control.

  Why: Goldenseal extract lowered metformin levels about 25 percent in an NCCIH-funded study of healthy adults.

  Applies to: metformin.

  Source wording: "This drop was enough to potentially hinder glucose control in people with type 2 diabetes taking metformin."

  National Center for Complementary and Integrative Health, Goldenseal, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Goldenseal.

Echinacea

Echinacea: 1 documented medication interaction in NCCIH (1 minor), verified 2026-10-13.

• Minor Echinacea and immunosuppressants: minor interaction. Ask the doctor who prescribes your immunosuppressant before taking it.

  Why: There are theoretical reasons to suspect echinacea might interact with immunosuppressants.

  Applies to: immunosuppressants.

  Source wording: "there are theoretical reasons to suspect that echinacea might interact with immunosuppressants or caffeine"

  National Center for Complementary and Integrative Health, Echinacea, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Echinacea.

Licorice root also licorice, glycyrrhizin

Licorice root: 1 documented medication interaction in NCCIH (1 minor), verified 2026-10-13.

• Minor Licorice root and corticosteroids: minor interaction. Ask your prescriber before taking licorice root products with a corticosteroid.

  Why: Interactions between licorice and corticosteroids have been reported; the source does not describe them.

  Applies to: corticosteroids.

  Source wording: "Interactions between licorice and corticosteroids have been reported."

  National Center for Complementary and Integrative Health, Licorice Root, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

NCCIH: glycyrrhizin in licorice has been linked to severe adverse effects in people with hypertension or heart or kidney conditions. NCCIH

Checked against: National Center for Complementary and Integrative Health, Licorice Root.

Cranberry

Cranberry: 1 documented medication interaction in NCCIH (1 minor), verified 2026-10-13.

• Minor Cranberry and warfarin: minor interaction. Talk with your prescriber before using cranberry products on warfarin.

  Why: Evidence conflicts on whether cranberry interacts with warfarin.

  Applies to: warfarin.

  Source wording: "There is conflicting evidence about whether cranberry interacts with the anticoagulant (blood thinner) warfarin."

  National Center for Complementary and Integrative Health, Cranberry, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Cranberry.

Flaxseed (flaxseed oil) also flaxseed oil, linseed

Flaxseed (flaxseed oil): 2 documented medication interactions in NCCIH (2 minor), verified 2026-10-13.

• Minor Flaxseed (flaxseed oil) and anticoagulants: minor interaction. Ask your prescriber before combining them.

  Why: There are theoretical reasons to suspect flaxseed might interact with anticoagulants.

  Applies to: anticoagulants.

  Source wording: "There are theoretical reasons to suspect that flaxseed or flaxseed oil might interact with other drugs, such as anticoagulant or antiplatelet drugs."

  National Center for Complementary and Integrative Health, Flaxseed and Flaxseed Oil, verified 2026-10-13.

• Minor Flaxseed (flaxseed oil) and antiplatelets: minor interaction. Ask your prescriber before combining them.

  Why: There are theoretical reasons to suspect flaxseed might interact with antiplatelet drugs.

  Applies to: antiplatelet drugs.

  Source wording: "There are theoretical reasons to suspect that flaxseed or flaxseed oil might interact with other drugs, such as anticoagulant or antiplatelet drugs."

  National Center for Complementary and Integrative Health, Flaxseed and Flaxseed Oil, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Flaxseed and Flaxseed Oil.

Cinnamon also cassia

Cinnamon: 1 documented medication interaction in NCCIH (1 minor), verified 2026-10-13.

• Minor Cinnamon and chemotherapy: minor interaction. Ask your oncologist before taking cinnamon supplements.

  Why: There are theoretical reasons to suspect some components of cinnamon may interact with an anticancer medicine.

  Applies to: an anticancer medicine (not named).

  Source wording: "there are theoretical reasons to suspect that some components of cinnamon may interact with an anticancer medicine or nicotine"

  National Center for Complementary and Integrative Health, Cinnamon, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Cinnamon.

Chamomile

Chamomile: 3 documented medication interactions in NCCIH (3 minor), verified 2026-10-13.

• Minor Chamomile and benzodiazepines/sedatives: minor interaction. Ask your pharmacist before combining them.

  Why: There are theoretical reasons to suspect chamomile might interact with sedatives.

  Applies to: sedatives.

  Source wording: "there are theoretical reasons to suspect that chamomile might interact with other drugs as well, such as sedatives"

  National Center for Complementary and Integrative Health, Chamomile, verified 2026-10-13.

• Minor Chamomile and birth control pills: minor interaction. Ask your prescriber or pharmacist before taking chamomile supplements on the pill.

  Why: Chamomile might have estrogen-like effects; preliminary studies suggest it might decrease the effect of birth control pills.

  Applies to: birth control pills.

  Source wording: "Preliminary studies suggest that taking chamomile along with birth control pills might decrease the effects of birth control pills."

  National Center for Complementary and Integrative Health, Chamomile, verified 2026-10-13.

• Minor Chamomile and warfarin: minor interaction. Ask your prescriber before taking chamomile supplements on warfarin.

  Why: Interactions between chamomile and warfarin have been reported.

  Applies to: warfarin.

  Source wording: "Interactions between chamomile and some drugs metabolized by the liver and warfarin (a blood thinner) have been reported"

  National Center for Complementary and Integrative Health, Chamomile, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, immunosuppressants, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Chamomile.

Bitter orange also synephrine, citrus aurantium

Bitter orange: 2 documented medication interactions in NCCIH or NIH ODS (2 moderate), verified 2026-10-13.

• Moderate Bitter orange and HIV medicines: moderate interaction. Do not take it with saquinavir without your HIV care team.

  Why: Bitter orange inhibits the CYP3A4 enzyme, raising blood levels of saquinavir.

  Applies to: saquinavir.

  Source wording: "Bitter orange has also been shown to inhibit CYP3A4 activity, leading to increased blood levels of certain drugs, such as cyclosporine and saquinavir"

  NIH Office of Dietary Supplements, Dietary Supplements for Weight Loss Fact Sheet for Health Professionals, verified 2026-10-13.

• Moderate Bitter orange and immunosuppressants: moderate interaction. Do not take it with cyclosporine unless your transplant team approves.

  Why: Bitter orange inhibits the CYP3A4 enzyme, raising blood levels of cyclosporine.

  Applies to: cyclosporine.

  Source wording: "Bitter orange has also been shown to inhibit CYP3A4 activity, leading to increased blood levels of certain drugs, such as cyclosporine and saquinavir"

  NIH Office of Dietary Supplements, Dietary Supplements for Weight Loss Fact Sheet for Health Professionals, verified 2026-10-13.

No well-documented interaction in NCCIH or NIH ODS for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Bitter Orange; NIH Office of Dietary Supplements, Dietary Supplements for Weight Loss Fact Sheet for Health Professionals.

Yohimbe also yohimbine

Yohimbe: 2 documented medication interactions in NCCIH (2 major), verified 2026-10-13. Most serious: MAOIs.

• Major Yohimbe and MAOIs: major interaction. Do not use yohimbe if you take an MAOI.

  Why: Yohimbe can interact with MAOI antidepressants, and yohimbine itself is linked to blood pressure problems and arrhythmia.

  Applies to: MAOIs.

  Source wording: "Do not use yohimbe if you are taking types of antidepressant medications called monoamine oxidase inhibitors or tricyclic antidepressants."

  National Center for Complementary and Integrative Health, Yohimbe, verified 2026-10-13.

• Major Yohimbe and tricyclics: major interaction. Do not use yohimbe if you take a tricyclic antidepressant.

  Why: Yohimbe can interact with tricyclic antidepressants.

  Applies to: tricyclic antidepressants.

  Source wording: "Do not use yohimbe if you are taking types of antidepressant medications called monoamine oxidase inhibitors or tricyclic antidepressants."

  National Center for Complementary and Integrative Health, Yohimbe, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Yohimbe.

Lavender also silexan

Lavender: 1 documented medication interaction in NCCIH (1 minor), verified 2026-10-13.

• Minor Lavender and benzodiazepines/sedatives: minor interaction. Ask your pharmacist before combining them, especially before surgery.

  Why: There are theoretical reasons to suspect lavender might interact with some sedatives.

  Applies to: sedative drugs.

  Source wording: "There are theoretical reasons to suspect that lavender might interact with some sedative drugs or herbs"

  National Center for Complementary and Integrative Health, Lavender, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Lavender.

Soy also soy isoflavones

Soy: 1 documented medication interaction in NCCIH (1 major), verified 2026-10-13. Most serious: MAOIs.

• Major Soy and MAOIs: major interaction. If you take an MAOI, follow your prescriber's tyramine diet advice, which covers these soy products.

  Why: High-tyramine soy foods such as tofu and soy sauce with MAOIs have caused dangerously high blood pressure.

  Applies to: MAOIs.

  Source wording: "have been reported (i.e., dangerously high blood pressure)"

  National Center for Complementary and Integrative Health, Soy, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Soy.

Aloe (aloe latex) also aloe vera

Aloe (aloe latex): 1 documented medication interaction in NCCIH (1 moderate), verified 2026-10-13.

• Moderate Aloe (aloe latex) and digoxin/ivabradine: moderate interaction. Do not use aloe latex products with digoxin without your prescriber.

  Why: Overuse of aloe latex may increase the risk of adverse effects from digoxin.

  Applies to: digoxin (cardiac glycosides).

  Source wording: "Overuse of aloe latex may increase the risk of adverse effects from cardiac glycosides, such as digoxin"

  National Center for Complementary and Integrative Health, Aloe Vera, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Aloe Vera.

Dandelion

Dandelion: 4 documented medication interactions in NCCIH (4 minor), verified 2026-10-13.

• Minor Dandelion and anticoagulants: minor interaction. Ask your prescriber before combining them.

  Why: There are theoretical reasons to suspect dandelion might interact with anticoagulants.

  Applies to: anticoagulants.

  Source wording: "There are theoretical reasons to suspect that dandelion might interact with antidiabetes, anticoagulant, antiplatelet, and water pill drugs, among others."

  National Center for Complementary and Integrative Health, Dandelion, verified 2026-10-13.

• Minor Dandelion and antiplatelets: minor interaction. Ask your prescriber before combining them.

  Why: There are theoretical reasons to suspect dandelion might interact with antiplatelet drugs.

  Applies to: antiplatelet drugs.

  Source wording: "There are theoretical reasons to suspect that dandelion might interact with antidiabetes, anticoagulant, antiplatelet, and water pill drugs, among others."

  National Center for Complementary and Integrative Health, Dandelion, verified 2026-10-13.

• Minor Dandelion and diabetes medicines: minor interaction. Ask your prescriber before combining them.

  Why: There are theoretical reasons to suspect dandelion might interact with diabetes drugs.

  Applies to: antidiabetes drugs.

  Source wording: "There are theoretical reasons to suspect that dandelion might interact with antidiabetes, anticoagulant, antiplatelet, and water pill drugs, among others."

  National Center for Complementary and Integrative Health, Dandelion, verified 2026-10-13.

• Minor Dandelion and diuretics: minor interaction. Ask your prescriber before combining them.

  Why: There are theoretical reasons to suspect dandelion might interact with diuretics.

  Applies to: water pills.

  Source wording: "There are theoretical reasons to suspect that dandelion might interact with antidiabetes, anticoagulant, antiplatelet, and water pill drugs, among others."

  National Center for Complementary and Integrative Health, Dandelion, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, statins, thyroid medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Dandelion.

Astragalus

Astragalus: 1 documented medication interaction in NCCIH (1 minor), verified 2026-10-13.

• Minor Astragalus and immunosuppressants: minor interaction. Ask the doctor who prescribes your immunosuppressant before taking it.

  Why: Astragalus may interact with drugs that suppress the immune system.

  Applies to: immunosuppressants.

  Source wording: "Also, astragalus may interact with medications that suppress the immune system."

  National Center for Complementary and Integrative Health, Astragalus, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Astragalus.

Feverfew

Feverfew: 1 documented medication interaction in NCCIH (1 minor), verified 2026-10-13.

• Minor Feverfew and migraine medicines: minor interaction. Ask your prescriber or pharmacist before combining them.

  Why: NCCIH states feverfew may interact with some medicines, including those used for migraine, without describing the effect.

  Applies to: migraine medicines.

  Source wording: "Feverfew may interact with some medicines, including those used for migraine."

  National Center for Complementary and Integrative Health, Feverfew, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Feverfew.

SAMe also s-adenosyl-l-methionine, s-adenosylmethionine

SAMe: 2 documented medication interactions in NCCIH (1 moderate, 1 minor), verified 2026-10-13.

• Moderate SAMe and levodopa: moderate interaction. Ask your neurologist before taking SAMe with levodopa.

  Why: SAMe may decrease the effects of levodopa.

  Applies to: levodopa (L-dopa).

  Source wording: "SAMe may decrease the effects of levodopa (L-dopa), a drug used to treat Parkinson’s disease."

  National Center for Complementary and Integrative Health, S-Adenosyl-L-Methionine (SAMe): In Depth, verified 2026-10-13.

• Minor SAMe and SSRIs/SNRIs: minor interaction. Ask your prescriber before combining SAMe with an antidepressant.

  Why: It is possible SAMe might interact with drugs that increase serotonin, such as antidepressants.

  Applies to: antidepressants that raise serotonin.

  Source wording: "SAMe might interact with drugs and dietary supplements that increase levels of serotonin"

  National Center for Complementary and Integrative Health, S-Adenosyl-L-Methionine (SAMe): In Depth, verified 2026-10-13.

No well-documented interaction in NCCIH for: MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, S-Adenosyl-L-Methionine (SAMe): In Depth.

Glucosamine and chondroitin also glucosamine, chondroitin

Glucosamine and chondroitin: 1 documented medication interaction in NCCIH (1 moderate), verified 2026-10-13.

• Moderate Glucosamine and chondroitin and warfarin: moderate interaction. Ask your prescriber before taking them with warfarin.

  Why: Glucosamine and chondroitin have been associated with an increased risk of bleeding in people taking warfarin.

  Applies to: warfarin.

  Source wording: "glucosamine and chondroitin have been associated with an increased risk of bleeding in people who are taking the anticoagulant warfarin"

  National Center for Complementary and Integrative Health, Glucosamine and Chondroitin for Osteoarthritis, verified 2026-10-13.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Glucosamine and Chondroitin for Osteoarthritis.

Black cohosh

Black cohosh: no well-documented medication interaction in NCCIH, verified 2026-10-13. That is not the same as safe; ask your pharmacist.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Black Cohosh.

Milk thistle also silymarin

Milk thistle: no well-documented medication interaction in NCCIH, verified 2026-10-13. That is not the same as safe; ask your pharmacist.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Milk Thistle.

Saw palmetto

Saw palmetto: no well-documented medication interaction in NCCIH, verified 2026-10-13. That is not the same as safe; ask your pharmacist.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Saw Palmetto.

Ginger

Ginger: no well-documented medication interaction in NCCIH, verified 2026-10-13. That is not the same as safe; ask your pharmacist.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Ginger.

Elderberry also sambucus

Elderberry: no well-documented medication interaction in NCCIH, verified 2026-10-13. That is not the same as safe; ask your pharmacist.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

Checked against: National Center for Complementary and Integrative Health, Elderberry.

Hawthorn

Hawthorn: no well-documented medication interaction in NCCIH, verified 2026-10-13. That is not the same as safe; ask your pharmacist.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

NCCIH: one study of a hawthorn preparation in heart failure patients raised the possibility of an interaction with their drugs; no drug is named. NCCIH

Checked against: National Center for Complementary and Integrative Health, Hawthorn.

Red yeast rice also monacolin k

Red yeast rice: no well-documented medication interaction in NCCIH, verified 2026-10-13. That is not the same as safe; ask your pharmacist.

No well-documented interaction in NCCIH for: SSRIs/SNRIs, MAOIs, anticoagulants, antiplatelets, statins, thyroid medicines, diabetes medicines, blood pressure medicines, benzodiazepines/sedatives, immunosuppressants, birth control pills, antibiotics, acid reducers, chemotherapy, lithium, anticonvulsants.

NCCIH: red yeast rice can contain monacolin K, which is identical to lovastatin, so it can have the same types of drug interactions as statin drugs. NCCIH

Checked against: National Center for Complementary and Integrative Health, Red Yeast Rice.