Resveratrol—A Natural Skin Whitening Agent

The multitude of colors in our skin—from basic skin tone to freckles, birth marks, and age spots—are created by pigments collectively called melanin, which is produced by organelles called melanosomes within melanocyte skin cells. The main enzyme involved in melanin production is tyrosinase. Skin color varies between individuals based on:^254-255

• Genetics and race, which determines how many melanosomes are in each melanocyte, the number of melanocytes, and how and where they are distributed in the skin layers.
• Environmental factors that affect pigment production in the skin.

The primary environmental influence on skin pigmentation is sun exposure. Ultraviolet radiation (UV) from the sun stimulates melanin production by activating the tyrosinase and other enzymes in melanocytes, as well as causing DNA damage that affects how melanin is distributed in the skin.^254-255

There aren’t many people, especially women, who are happy to find the visible evidence of sun and free radical damage showing up as dark spots on their skin as they get older—hence the multitude of skin lightening agents on the market. These hyperpigmented areas (e.g., age or liver spots, freckles, and melasma) can also occur when skin heals from acne and even cosmetic treatments such as peels and laser resurfacing, but the root cause is thought to be dysfunctional regulation of melanin production in the skin.²⁵⁶

As safety concerns over commonly used hydroquinone have been raised, cosmetic companies have become increasingly interested in finding other natural skin lighteners. Flavonoids are natural chemical compounds in plants that have biological effects on humans and animals—many of them modern scientists are discovering as beneficial. Belonging to the stilbene subgroup of flavonoids, resveratrol can mildly inhibit tyrosinase, the enzyme which skin pigment cells produce that in turn controls melanin. Piceatannol, a derivative compound of resveratrol, has been shown to inhibit pigmentation caused by UV light exposure (as in sunlight), believed to be attributable to resveratrol’s potent antioxidant effects.²⁵⁶

How Does It Work?

In general, skin lighteners work by one or more mechanisms:

• Reducing production of tyrosinase enzymes.²⁵⁵
• ²⁵⁰
• Increased shedding of the upper layer of dead skin cells to remove excess melanin.²⁵⁵
• Spreading the melanin thinner by regulating the MITF genes that produce proteins which help move melanin from melanocytes to other skin cells.²⁵⁵
• Degrading existing melanosomes.²⁵⁵

Resveratrol appears to work by inhibiting tyrosinase, MITF, and DCT activity.²⁵⁷

Evidence of Benefit

Lab studies indicate that resveratrol directly inhibits the tyrosinase enzyme and also blocks it from maturing and becoming functional.²⁵⁷ Recently published results on a resveratrol derivative (5HNB) showed significant tyrosinase inhibition. In fact, 5HNB was far more potent than the commercially-used skin lightener kojic acid.²⁵⁸

In an animal study, dark-skinned swine treated with a topical application of 1% resveratrol showed significant skin lightening effect. Further placebo-controlled studies demonstrated that animals treated with topical resveratrol (both before and after UVB exposure) had significantly less skin-darkening than untreated animals exposed to UVB.²⁵⁹

A number of different botanical substances that contain resveratrol and resveratrol analogs, isomers, or derivatives have been lab-tested for their skin lightening effects. The plants that have shown the most powerful skin lightening effects include:

Oxyresveratrol, an analog of resveratrol, has been shown in studies to have the greatest lightening effect. Two separate clinical studies demonstrated oxyresveratrol’s skin whitening potency:²⁶⁴

• Sixty women were divided into groups and applied a test sample of either licorice, kojic acid, or oxyresveratrol extract from A. lakoocha on one arm. After only four weeks the participants who used the oxyresveratrol showed visible skin lightening (compared to the untreated arm), while the kojic acid and licorice-treated participants had lightening after six and ten weeks. The oxyresveratrol produced greater lightening effects than both kojic acid and licorice overall from the fourth week on.
• In a 1% lotion form oxyresveratrol from A. lakoocha demonstrated faster and greater skin bleaching than a 1% licorice lotion in a clinical study involving 50 women.

Clinical studies, performed by manufacturers, of skin lighteners containing resveratrol (or resveratrol derivatives) have shown promising results as well:

Other skin lightening products that contain resveratrol:

• MyChelle Dermaceuticals Apple Brightening Serum
• Pigeon Creek’s Natural Skin Lightener Soap