Resveratrol

resveratrol · trans-resveratrol

An 'anti-aging' polyphenol claimed to activate sirtuins.

TypeSupplement / dietary

The grade answers: What does the human evidence support for: Sirtuin / antioxidant activity?

Structure · PubChem

Grade

Limited

The grade rates evidence quality — it is not advice to take or buy.

Class: Antioxidants
Primary use: Sirtuin / antioxidant activity
Evidence strength: low
Last reviewed: 2025-09-01

Bottom line

Impressive in a petri dish, inconsistent in people. Poor absorption means most of a dose never reaches tissues intact — the clearest lesson in why cell data don't equal human benefit.

What the evidence says

Resveratrol became famous on the promise that it mimics caloric restriction by activating SIRT1. In cells and short-lived animals the signals were exciting; in humans the trials are small, heterogeneous and often null. A recurring theme is bioavailability: oral resveratrol is metabolised so rapidly that plasma levels of the active form stay very low. The honest read is grade C — plausible mechanism, real safety, but human clinical benefit that hasn't held up consistently.

Key studies

[1]
Calorie-restriction-like effects of resveratrol in humans · RCT
An early positive metabolic signal in a small trial — not consistently reproduced.
Open on PubMed ↗
[2]
Resveratrol supplementation: systematic review of human trials · review
Across trials, effects on hard clinical outcomes are inconsistent.
Open on PubMed ↗
[3]
Bioavailability and metabolism of oral resveratrol · pharmacokinetic
Explains the gap: rapid conjugation leaves little free compound in circulation.
Open on PubMed ↗

See all studies on PubMed ↗

Scoped PubMed search, not a curated bibliography: the individual PMIDs for this entry have not yet been verified one by one. For that reason it is not used to support a high grade and is awaiting review.

Mechanism

Proposed activation of SIRT1 and modulation of AMPK and antioxidant pathways. In practice the in-vivo effect is blunted by extensive first-pass metabolism to sulphate and glucuronide conjugates, so exposure of target tissues to free resveratrol is limited.

Safety

Generally well tolerated at moderate supplemental doses. High doses can cause gastrointestinal upset and may interact with drugs metabolised by the same liver enzymes (and with anticoagulants/antiplatelets). Purity and dose vary widely between products.

Dosage context

Studies span roughly 150 mg to 1 g/day with no consensus regimen. Formulation matters more than headline dose because of the absorption problem; micronised or co-formulated products are marketed on this basis but without decisive outcome data.

Examples of application

Taken with a fatty meal to blunt the poor absorption a little.
Often combined with pterostilbene, sold on better bioavailability.
Cheap to try, but with weak human evidence.

From the field

A classic case where preclinical enthusiasm didn't translate to people. We keep resveratrol at C not because it's unsafe, but because the human evidence never matched the marketing.

Related molecules

NMNB QuercetinC

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