Resveratrol and medications: what to check

The one interaction study we can verify found that 1,000 mg of resveratrol a day for 4 weeks changed how several medicine-processing liver enzymes worked in 42 healthy adults. If you take any prescription medication, including a blood thinner or a diabetes medicine, ask your doctor or pharmacist before starting resveratrol.

What the study found

Researchers measured four enzymes that process medicines (CYP1A2, CYP2D6, CYP2C9 and CYP3A4) in 42 healthy volunteers before and after 4 weeks of 1 g of resveratrol once a day. They did this by giving harmless probe compounds and watching how fast they were cleared. Resveratrol inhibited the activity indices for CYP3A4, CYP2D6 and CYP2C9 and induced CYP1A2. The authors concluded that "pharmacologic doses" could lead to more adverse drug reactions or altered drug efficacy through these changes. They also suggested that future work should look at lower doses to limit these interactions.

What it does not tell us: it tested no prescription drug, it involved healthy people (not people on regular medication), the form of resveratrol was not given in the abstract, and it used one dose. It is a reason to ask, not a list of drugs that interact.

What this means at our label's dose

Electric Tiger Resveratrol is directed at one capsule twice a day. By the label's 50% trans-resveratrol figure (arithmetic; no certificate of analysis on file) that is about 600 mg a day, below the 1,000 mg in the study. We do not know whether that lower amount changes these enzymes, so we treat the caution as applying to anyone on prescription medicine. Label facts are on the product page.

Is resveratrol a blood thinner?

We found no verified trial testing resveratrol alongside a blood thinner, and we do not describe resveratrol as one. Two of the enzymes in the study above (CYP2C9 and CYP3A4) are involved in how some blood thinners are processed, but the study did not test any, so what that means for a given person is unknown. The caution is a general one: if you take a blood thinner or an antiplatelet medicine, such as warfarin or apixaban (Eliquis), ask your prescriber or pharmacist before starting resveratrol, and tell them what you take.

What to ask your doctor or pharmacist

• Bring the Supplement Facts panel: 600 mg of knotweed root complex per capsule, labelled 50% trans-resveratrol, two capsules a day.
• Ask whether any of your medicines are processed by CYP3A4, CYP2D6, CYP2C9 or CYP1A2.
• Say whether you take supplements, which can add up.
• Ask before changing the timing or amount of any prescribed medicine. Do not change it yourself.

Questions people ask

How does resveratrol interact with prescription medications?

The only study we can verify suggests it can change how some liver enzymes that process medicines work, at 1 g a day. Which medicines are affected depends on the medicine; ask a pharmacist.

Can you take resveratrol with Eliquis?

We cannot say it is safe, and we found no study that tested the pair. Ask the prescriber of your blood thinner.

Can you take resveratrol with metformin, or does it work with it?

We found no verified trial of the pairing and we do not describe any combined effect. If you take metformin or any prescription medicine for blood sugar, ask your doctor before adding resveratrol, and never replace a prescribed medicine with a supplement.

What about NAD or other supplements?

We do not sell or review combinations. Tell your doctor or pharmacist everything you take.

Where can I read more?

Side effects: resveratrol side effects. Cautions by group: who should not take resveratrol.