Antioxidant Interactions: A Reference Table by Compound and Medicine Class
A reference table of documented antioxidant supplement interactions by compound and medicine class, with the source, year and strength of evidence for each row.
Content last updated . This page has not been medically reviewed.
How to use this table
This is a lookup table, not advice. It lists interactions that the sources we read describe. A blank or "not described" entry does not mean "no interaction"; it means we did not read a source that covers it. Lack of evidence is not proof of safety.If you take warfarin or another blood thinner, insulin or other diabetes medicines, a cholesterol-lowering drug, a transplant medicine, or are having cancer treatment, ask a pharmacist or clinician before using any item below, and never stop a prescribed medicine on your own. General guidance: medication interactions and interactions by drug class.
Evidence labels: official statement (a health agency says so), case reports, mechanistic or review-level, and trial-level.
Reference table
| Compound (form) | Medicine class or situation | What the source says | Source, year | Strength |
|---|---|---|---|---|
| Vitamin E (high-dose supplements) | Anticoagulant or antiplatelet medicines | May interact; high doses may raise bleeding risk | NCCIH, 2023 [1] | Official statement |
| Vitamin C (supplements) | Cancer chemotherapy and radiation | May interact with cancer treatments | NCCIH, 2023 [1] | Official statement |
| Vitamin C (supplements) | Iron overload (hemochromatosis) | Can worsen iron overload | NCCIH, 2023 [1] | Official statement |
| Vitamin E + vitamin C + selenium + beta-carotene together | Two cholesterol-lowering drugs taken together | In one study the combination reduced their cholesterol-lowering effect | NCCIH, 2023 [1] | One study |
| Any antioxidant (vitamins A, C, E, carotenoids, CoQ10) | Breast cancer chemotherapy | Use was linked to higher recurrence and death in a 1,134-woman study; participants chose their own supplements, so bias is possible | NCCIH, 2023 [1] | Observational |
| Antioxidants in general | Radiotherapy | May reduce side effects but could compromise treatment; recommendations premature | Systematic review, 2025 [2] | Review-level |
| CoQ10 | Warfarin; insulin | May change how the body uses warfarin and insulin | NCI (patient PDQ page) [3]; NCCIH, 2019 [4] | Official statement |
| CoQ10 | Drugs for cholesterol, blood pressure, blood sugar | Such drugs may decrease CoQ10's effects | NCI [3] | Official statement |
| Alpha-lipoic acid | Diabetes (insulin autoimmune syndrome, low blood sugar) | Reported as a trigger of this rare syndrome in susceptible people; cases described as "increasingly recognized" | Case report 2018 [5]; narrative review 2026 [6] | Case reports |
| Green tea (extract) | Nadolol (beta-blocker); atorvastatin; raloxifene | Green tea at high doses reduced nadolol blood levels; extract can reduce atorvastatin levels; an interaction with raloxifene was shown | NCCIH, 2025 [7] | Official statement |
| Curcumin / turmeric | Medicines in general | NCCIH says some herbs and medicines interact in harmful ways; specific drug pairs are on the curcumin safety page | NCCIH, 2025 [8] | Official statement (general) |
| Berberine | Medicines in general | May interact with some medicines | NCCIH, 2023 [9] | Official statement |
| Berberine | Cyclosporine (transplant) and CYP-enzyme medicines | A 2026 review describes increased cyclosporine exposure in transplant recipients and enzyme inhibition; treat as an active interacting agent | Narrative review, 2026 [10] | Review-level |
| Berberine | Medicines handled by CYP enzymes | Co-use should be considered because berberine inhibits these enzymes | Toxicology review, 2017 [11] | Review-level |
| Beta-carotene | Smoking (not a medicine) | Higher lung cancer risk in smokers and asbestos-exposed workers | ATBC 1994 [12]; CARET 1996 [13] | Trial-level |
Compounds with no interaction data in the sources we read
For quercetin, resveratrol, glutathione, astaxanthin, lutein, zeaxanthin, lycopene, grape seed extract and N-acetylcysteine, interaction details are not described in the sources we read for this page. Proper evidence not found here does not mean none exists; use the dedicated pages and a pharmacist. See quercetin, resveratrol and glutathione.Reading the table safely
- Interactions depend on the form and amount; a finding for one form (for example ubiquinone) should not be assumed for another.
- Products may contain more than listed on the label; NCCIH notes that what is on the label may not be what is in the product, and quality testing helps only partly. [14] See quality testing and certifications.
- Bring the real label to your pharmacist so they can check each ingredient.
Frequently asked questions
Does CoQ10 interact with warfarin?
NCCIH says CoQ10 may interact with warfarin and insulin. Ask your prescriber or pharmacist. [4]
Does vitamin E interact with blood thinners?
NCCIH says vitamin E supplements may interact with anticoagulant or antiplatelet medicines. [1]
Can green tea extract affect my medicines?
NCCIH describes lower blood levels of nadolol and atorvastatin and an interaction with raloxifene. [7]
Is alpha-lipoic acid a concern with diabetes medicines?
Case reports link it to insulin autoimmune syndrome, a rare cause of low blood sugar. [5]
Does berberine interact with medicines?
NCCIH says it may, and a 2026 review describes enzyme-related interactions. [9][10]
References
- NCCIH, Antioxidant Supplements: What You Need To Know (July 2023). Read 2026-10-23.
- Limbrunner et al., The influence of antioxidant supplementation on adverse effects and tumor interaction during radiotherapy: a systematic review (Clin Exp Med 2025). Read 2026-10-23.
- National Cancer Institute, Coenzyme Q10 (PDQ) patient version. Read 2026-10-23.
- NCCIH, Coenzyme Q10 (Jan 2019). Read 2026-10-23.
- Cappellani et al., Spontaneously remitting insulin autoimmune syndrome in a patient taking alpha-lipoic acid (Endocrinol Diabetes Metab Case Rep 2018). Read 2026-10-23.
- Vallianou et al., Alpha-lipoic acid as a trigger of insulin autoimmune syndrome: narrative review (Metabol Open 2026). Read 2026-10-23.
- NCCIH, Green Tea (Feb 2025). Read 2026-10-23.
- NCCIH, Turmeric (Apr 2025). Read 2026-10-23.
- NCCIH, Diabetes and Dietary Supplements (Nov 2023). Read 2026-10-23.
- Dumitru et al., Berberine-drug interactions: mechanisms, clinical relevance and risk stratification, a narrative review (Pharmaceuticals 2026). Read 2026-10-23.
- Rad et al., Toxicology effects of Berberis vulgaris (barberry) and its active constituent, berberine: a review (Iran J Basic Med Sci 2017). Read 2026-10-23.
- ATBC Study Group, The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers (N Engl J Med 1994). Read 2026-10-23.
- Omenn et al., Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease, CARET (N Engl J Med 1996). Read 2026-10-23.
- NCCIH, Using Dietary Supplements Wisely (2019). Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.