Collagen for skin brightening?

Frequent and prolonged exposure to the sun, hormonal fluctuations, or even skin inflammation: these are just some of the causes of a hyperpigmentation condition. Although it can occur in all skin tones, pigmentation disorders are more common in darker phototypes (IV to VI) and are challenging to treat. This phenomenon occurs due to a disruption in melanogenesis: melanin, the pigment responsible for skin colouration, is overproduced in certain areas.

While certain ingredients or cosmetic actives, such as tranexamic acid, retinol or glycolic acid, have the ability to lighten the skin, this does not appear to be the case with collagen. Indeed, to date, no scientific study has reported depigmenting properties of this molecule when used in topical application. One might possibly assume a preventive effect of collagen on hyperpigmentation due to its antioxidant virtues. By donating an electron to free radicals, this protein protects skin cells from oxidative stress, one of the factors causing skin tone dullness.

The situation is similar for the oral intake of collagen, of which only two studies have suggested that it could lighten the skin. Conducted in a double-blind manner, the first involved 44 volunteers with pigmentation disorders. Divided into 3 groups, these individuals took daily 5g of collagen peptide, 5g of collagen peptide fermented by Aspergillus sojae or a placebo. After 3 months, the researchers measured a decrease in pigmentation of 46% for the volunteers in the first group and 48% for those in the second. No effect was measured for those who received the placebo. The scientists hypothesised about the anti-tyrosinase properties of collagen, although the exact mechanism has not yet been elucidated.

Another study was conducted with 62 individuals suffering from melasma. They were invited to take 10g of a dietary supplement containing marine collagen, soy peptide, and chrysanthemum extract or a placebo daily. Before and after 60 days, their skin tone uniformity was evaluated using a chromameter, and melanin density was measured with a mexameter. Overall, the melasma areas of the participants decreased by 17% for the "dietary supplement" group and by 10% for the "placebo" group, but this difference was not significant. In this study, although an improvement in skin pigmentation was observed, it is not possible to attribute it to the collagen as the placebo, containing no active substance, yielded similar results.

The key takeaway:

• No study has demonstrated that topical application of collagen can lighten the skin.

• There have been few studies conducted on the depigmenting properties of this compound when taken orally, and their findings contradict each other.