Resveratrol is a plant compound found in grape skins, peanuts, some berries, and red wine. Human studies suggest a few possible metabolic and blood-vessel effects, but results vary by population and outcome; it is not a stand-in for prescribed medicine.
Its best-known form is trans-resveratrol. It is absorbed after oral use but is rapidly changed and cleared by the body, which helps explain why findings from cells and animals do not automatically carry over to people.
Resveratrol quick facts
| Question | What human research reports |
|---|---|
| Forms | Resveratrol occurs as cis and trans forms; trans-resveratrol is the form most often named in human research. Piceid is a glucose-bound form found in grapes and grape juice. |
| Doses used | Studies range from 8 mg a day in grape supplements to 5 g a day in short safety studies. Researchers also used 30 to 400 mg in vascular studies and 100 mg a day in one metabolic-syndrome trial. |
| Typical study length | Single-dose studies, one month, several months, and one-year trials all appear in the research. |
| Main studied uses | Blood-vessel measures, glucose and lipid measures, body measurements, cognition, and assisted reproduction outcomes. |
| Food sources | Grapes, grape juice, peanuts, cocoa, and berries including blueberries, bilberries, and cranberries. |
For a useful way to separate a study result from a broad label promise, see ingredient evidence marketing claims.
What do human studies show?
Blood pressure, cholesterol, and waist size
The broadest recent assessment is a 2026 umbrella review of 45 systematic reviews of randomized controlled trials, covering 129 associations and 68 outcomes. It rated evidence as high certainty for a mean 0.80 cm lower waist circumference, a 0.19 mmol/L lower total cholesterol level among adults with overweight, and lower blood pressure among people with type 2 diabetes: 3.55 mmHg lower diastolic and 7.97 mmHg lower systolic pressure. Those are average study findings, not a promise of an individual result. Read the 2026 umbrella review for its outcome definitions and certainty ratings.
Blood sugar and lipids in type 2 diabetes
Results conflict here. A 2026 umbrella review and meta-analysis of 10 meta-analyses in people with type 2 diabetes found no significant overall effects on fasting blood sugar, HbA1c, insulin, insulin resistance, HDL cholesterol, triglycerides, or total cholesterol, despite substantial differences between the included studies. It found an LDL-cholesterol reduction in one standardized analysis and lower insulin in larger evidence sets, but concluded resveratrol was not a beneficial agent for glycemic and lipid measures overall. See the diabetes umbrella review for the full analysis.
An older randomized, placebo-controlled trial described by the Linus Pauling Institute used 10 mg daily for four weeks in 19 men with type 2 diabetes and reported lower insulin resistance. That small, short trial cannot settle the wider question. The Institute also notes that studies in otherwise healthy adults with overweight or obesity found little or no metabolic benefit.
Blood-vessel function
Several trials measured flow-mediated dilation, a test of how an artery widens. In a six-month cross-over study of 34 people with metabolic syndrome, participants received 100 mg daily for three months; flow-mediated dilation improved during supplementation and returned to baseline within three months after it ended. The formulation also contained vitamin D3, quercetin, and rice-bran phytate, so the result cannot be assigned to resveratrol alone.
Other research summarized by the Linus Pauling Institute included single doses of 30, 90, or 270 mg in healthy adults with overweight or obesity, plus a six-month 75 mg daily study. These trials reported improved flow-mediated dilation. A separate one-year trial in 75 people at higher cardiovascular risk used a grape supplement supplying 8 mg daily for six months and 16 mg daily for another six months; it reported changes in inflammatory and clotting-related markers. These are markers rather than proof of fewer heart events.
Weight, cognition, and aging claims
The 2026 umbrella review found a small average waist-circumference difference, but that does not make resveratrol a weight-loss treatment. For memory and cognitive performance, Memorial Sloan Kettering reports that a meta-analysis found no significant effect and that more recent double-blind trials in older adults also found no cognitive-function benefit. Claims about longer life remain untested in people: lifespan findings came from experimental organisms, not human longevity trials.
Women, fertility, estrogen, and men
A 2026 systematic review and meta-analysis included seven studies with 3,411 people undergoing assisted reproduction; 274 received resveratrol. Fertilization rates were higher on average, but there were no significant differences in clinical pregnancy, live birth, embryo count, retrieved eggs, or mature eggs overall. The authors said larger, better-designed trials are needed. Read the assisted-reproduction review for the complete results.
Resveratrol has estrogen-like activity in laboratory research. That is different from showing that it raises estrogen levels in people. Memorial Sloan Kettering also notes activity involving androgen receptors; this does not show that resveratrol raises testosterone. People with hormone-sensitive cancers should discuss a supplement with their treating clinician first.
Skin and face claims
There is no broad human evidence here to support a face or skin-result promise from an oral resveratrol supplement. Memorial Sloan Kettering reports a case of contact dermatitis from resveratrol in a cosmetic cream. A topical product and an oral supplement are not interchangeable.
What doses did researchers use?
These are research doses, not a suggested dose. Study design matters as much as the number on a bottle; this is why zinc benefits doses studied safety evidence also separates study dose from a personal recommendation.
| Study context | Amount and duration researchers used | What was measured |
|---|---|---|
| Metabolic syndrome cross-over trial | 100 mg/day for three months | Flow-mediated dilation |
| Healthy adults with overweight or obesity | Single 30 mg, 90 mg, or 270 mg doses | Flow-mediated dilation about 60 minutes later |
| Six-month vascular study | 75 mg once or 75 mg/day | Flow-mediated dilation |
| Grape-supplement trial | 8 mg/day for six months, then 16 mg/day for six months | Inflammatory and clotting-related markers |
| Short safety research | More than 1,000 mg/day for up to 29 days; 2,000 mg twice daily for two eight-day periods | Gastrointestinal effects |
What are the downsides and side effects?
The main reported side effects at higher supplemental doses are nausea, stomach pain, gas, and diarrhea. The Linus Pauling Institute reports mild-to-moderate gastrointestinal effects in people taking more than 1,000 mg daily for up to 29 days; six of eight people taking 2,000 mg twice daily during two eight-day periods reported mild diarrhea. Memorial Sloan Kettering likewise lists nausea, gas, abdominal pain, and diarrhea at high doses.
There is no human finding in these sources that resveratrol is hard on the liver. A high-dose micronized resveratrol trial in people with multiple myeloma was halted after serious adverse events including kidney failure; the Linus Pauling Institute says kidney failure is also a frequent complication of myeloma, so the cases could not be assigned solely to the formulation.
What should you not mix with resveratrol?
Bring a full medication and supplement list to a clinician or pharmacist before using a resveratrol supplement. Memorial Sloan Kettering says resveratrol may increase bleeding risk with antiplatelet medicines, and reports that 1 g daily for four weeks affected CYP3A4, CYP2D6, CYP2C9, CYP1A2 enzyme activity in healthy volunteers. Those enzymes help the body process many medicines, so an interaction review is more useful than guessing from a short list.
The Linus Pauling Institute also warns that long-term, high intake may affect medicines metabolized by cytochrome P450 enzymes, potentially changing effectiveness or toxicity. Do not start, stop, or change a prescribed medicine based on a supplement page.
Who should talk to a clinician first?
- Anyone taking blood thinners, antiplatelet medicines, or medicines processed through CYP450 enzymes.
- Anyone with a bleeding disorder or an upcoming procedure.
- Anyone who is pregnant or breastfeeding; safety of resveratrol supplements in pregnancy and lactation has not been established.
- Anyone with a history of estrogen-sensitive cancer, including breast, ovarian, or uterine cancer.
- Anyone receiving cancer care or managing a chronic condition with prescription medicine.
Memorial Sloan Kettering advises patients to tell their health-care team about dietary supplements, because supplements can interact with medicines and affect care.
What is still unknown?
Human research has not established a safe and effective resveratrol dose for chronic disease prevention. Oral resveratrol has low bioavailability, meaning only a limited amount of unchanged compound reaches circulation before the body metabolizes and eliminates it. It is also unknown whether resveratrol prevents or treats cancer in people, extends human lifespan, or provides a reliable cognitive benefit.
There is no meaningful head-to-head human evidence here to rank resveratrol against NAD-related supplements or CoQ10. They are different compounds with different study questions, so “better” depends on the outcome you are trying to evaluate.
How do you read a resveratrol label?
Start with the serving size and the milligrams of resveratrol per serving. The Linus Pauling Institute says U.S. supplements can contain less than 1 mg to 500 mg per tablet or capsule, while research has used a much wider range. Look for whether the label names trans-resveratrol, cis-resveratrol, piceid, a grape extract, or Japanese-knotweed extract; those descriptions are not automatically interchangeable with the form used in a particular trial.
- Amount: Check milligrams per serving and servings per day.
- Form: Note whether the label specifically identifies trans-resveratrol or lists an extract.
- Blends: If a proprietary blend gives only a combined total, you cannot tell how much resveratrol it contains.
- Other ingredients: Compare them with the study you are using for context. Some vascular studies used multi-ingredient formulas, not resveratrol alone.
Before you order
- Ask a pharmacist to review your medicines if you use blood thinners, antiplatelet medicines, or several prescriptions.
- Choose a label that states the amount and form rather than relying on a blend total.
- Keep the study population in mind: a finding in people with type 2 diabetes, metabolic syndrome, or assisted reproduction may not apply to everyone.
- Use food sources for variety in your diet, but do not rely on red wine as a resveratrol strategy; wine content is variable and alcohol has separate health considerations.
By ClinicalStudyConnect.com Research Desk
This article is for general information purposes only and does not constitute medical advice. Consult your doctor or qualified healthcare provider before making changes to your health routine.