Resveratrol

Resveratrol is a polyphenol produced by plants as a defence compound, generated in response to stress such as injury, UV exposure or fungal attack. It is found in the skins of red grapes, in Japanese knotweed, in blueberries, cranberries and peanuts, and it is the compound behind a great deal of discussion about red wine and health, most of which has little bearing on what it does applied to skin.

Cosmetic resveratrol is generally extracted from Japanese knotweed, which contains it in far higher concentrations than grapes, or produced synthetically. On an ingredients list it appears as Resveratrol, and you may also see the more stable derivative Hydroxystilbene or blends with related polyphenols.

Typical cosmetic use sits around 0.5% to 1%. It is poorly soluble in water and unstable in light, which makes it awkward to formulate and is why it usually appears in oil-based or anhydrous products, in opaque packaging, and often as part of a blend with other antioxidants rather than alone.

Its instability in daylight is also why, unusually for an antioxidant, resveratrol is generally positioned as a night ingredient. Most antioxidants are recommended for the morning; this one tends to be recommended for the evening, for the straightforward reason that light degrades it.

It appears mainly in night serums, night creams and overnight treatments aimed at the look of dullness, uneven tone and general environmental wear.

Resveratrol is a free radical scavenger, and this is its primary and best-supported role. Environmental exposure and normal metabolism generate unstable molecules that damage cell structures over time, contributing to the appearance of dullness, uneven tone and loss of firmness. Resveratrol neutralises them directly.

Beyond that direct action, it appears to support the skin’s own antioxidant systems rather than simply adding to the pool from outside. This indirect route is generally considered more durable than direct scavenging, since it works with mechanisms the skin already has, and it is part of why resveratrol attracts interest despite being harder to formulate than more convenient antioxidants.

It has also been studied in connection with sirtuins, a family of proteins involved in how cells manage stress and repair. Much of this work sits well outside cosmetic skincare, in laboratory and non-topical settings, and it is worth treating the longevity claims that follow from it with a good deal of caution. What can reasonably be said is that resveratrol is a capable antioxidant with a plausible supporting role, not that applying it to the face influences how cells age.

There is also a modest calming effect and some evidence of an influence on pigment production, which is why it appears in products aimed at the look of uneven tone. Both are secondary to the antioxidant activity. As with all antioxidants, the benefit is protective and cumulative, showing up as skin holding its condition rather than as a visible change over a few weeks.

Resveratrol is unusual among antioxidants in being a night ingredient, and most of the practical advice follows from that.

• When: evening. It degrades in daylight, so a morning application wastes much of it.
• Order in the routine: after cleansing and any watery layers, before moisturiser. In an oil-based formula, later rather than earlier.
• Packaging matters. Opaque or dark, airless where possible. Resveratrol in a clear jar is not a good buy.
• Look for it in a blend. It is most often formulated alongside other antioxidants, which is sensible: antioxidants generally work better in combination than alone.
• Pairs well with: niacinamide, hyaluronic acid, peptides, ceramides and squalane.
• With a retinoid: both are night ingredients, so if you use both, alternate nights or apply the resveratrol product on the nights you are not using your retinoid.
• Sunscreen every morning. Antioxidant work at night is undone by unprotected days.
• Store it cool and dark. Heat and light are both problems.

Treat it as a supporting antioxidant rather than a headline active. It is a reasonable addition to a well-built routine and a poor substitute for sunscreen, retinoids or vitamin C.