Antioxydants et vieillissement cutané.

Limiting skin ageing with antioxidants?

Throughout life, the body's cells are subjected to oxidative stress. This refers to the generation of highly reactive molecules known as free radicals. These are ubiquitous in the process of cellular metabolism and can interact with DNA, proteins, and polyunsaturated fatty acids in the body, causing DNA chain breaks and oxidative damage such as lipid metabolism oxidation.
All these alterations are the primary internal causes of ageing and skin dysfunctions. This observation has led to a medical revolution that has emphasised the importance of antioxidants and free radical scavengers in the prevention and management of skin ageing.

Summary
Published October 17, 2022, updated on February 23, 2024, by Maylis, Chemical Engineer — 7 min read

Topical application of antioxidants.

In skincare, certain active ingredients are particularly effective in limiting the degradation of skin cells and their components by free radicals. Here is a non-exhaustive list.

  • Theferulic acid

    The hydroxy and phenoxy groups of ferulic acid donate electrons to deactivate free radicals by making them more stable and therefore less reactive. As such, this active ingredient delays skin ageing and protects the skin from external aggressions. At Typology, we have formulated the antioxidant serum which contains 3% ferulic acid. It is suitable for all skin types and effectively combats photo-ageing of the skin by restoring firmness and elasticity. It also helps to brighten and even out the complexion.

  • The vitamins C (L-ascorbic acid) and E (tocopherol)

    These active ingredients, renowned for their effectiveness in combating photoaging of the skin, need no introduction. Chemically, these two compounds possess free hydroxyl functions carried by aromatic cycles. These functions capture free radicals and stabilise them by providing the missing electron. As a result, they are less reactive and no longer degrade the compounds present at the level of skin cells. These two vitamins are present in our firmness & radiance complex. This serum offers a dual preventive and corrective action on the appearance of signs of ageing and restores radiance and uniformity to the skin.

  • The resveratrol

    Derived from Japanese knotweed, a plant from East Asia used in traditional Chinese and Japanese medicine, this polyphenol operates on two levels: it neutralises free radicals and prevents their formation. Thus, it has a dual preventive and corrective action against sources of oxidation, which helps to limit the premature ageing of the skin. This active ingredient is also present at a concentration of 3% in the antioxidant serum mentioned earlier.

  • The coenzyme Q10

    The coenzyme Q10 is referenced according to the INCI nomenclature under the name "ubiquinone". It is derived from bacterial fermentation using corn seeds (Zea mays L.) followed by a drying stage, then extraction and separation by silica gel chromatography. The compound is then purified to be safely incorporated into a cosmetic formula. Coenzyme Q10 operates on two levels to combat oxidative stress: it reduces the production of free radicals and it regenerates vitamin E, a powerful antioxidant present in the body.

  • The retinol

    Derived from the vitamin A, retinol is part of the retinoid family. The presence of unsaturations (carbon-carbon double bonds) on its side chain allows it to play an antioxidant role by capturing other reactive oxygen species. However, this high efficiency is accompanied by a recognised potential for irritation. The retinol can indeed cause redness and skin discomfort in subjects with sensitive or even atopic skin. In response to this, the European regulation has limited its concentration in non-rinsed cosmetic products to 0.3%. As a precaution, the use of retinol by pregnant and/or breastfeeding women is discouraged. As retinol is sensitive to light and can increase skin sensitivity when exposed to UV rays, use in the evening is preferred, for greater effectiveness. The following morning, a sun protection suited to one's phototype should be applied.

The ingestion of antioxidants.

In vivo oxidation, which ultimately leads to the ageing of the organism, has made exogenous antioxidant supplements, of which diet is a significant source, a subject of research for several years.

Thus, to limit skin ageing, it is recommended to consume foods rich in antioxidant compounds such as certain vitamins (vitamins A, C and E), polyphenols, carotenoids, bioflavonoids and trace elements (zinc, manganese or selenium).

Theindex ORAC (Oxygen Radical Absorbance Capacity) measures the free radical absorption capacity per 100 grams of food. The higher the ORAC index, the more quantitatively the food possesses antioxidant properties.

According to this index, here are the foods richest in antioxidants that should be consumed very regularly to slow down skin ageing: clove, cinnamon, oregano, turmeric, acai berries, cocoa (powder, unsweetened), cumin, parsley, basil, curry, broccoli, spinach.

Sources

  • BERGER M. M. Can oxidative damage be treated nutritionally? Clinical Nutrition (2005).

  • FRIGOLA A. & al. ORAC and TEAC assays comparison to measure the antioxidant capacity of food products. Food Chemistry (2009).

  • KAFI & al. Improvement of naturally aged skin with vitamin a (retinol). Archives of Dermatology (2007).

  • MASAKI H. Role of antioxidants in the skin: anti-aging effects. Journal of Dermatological Science (2010).

  • YANG H. L. & al. The in vitro and in vivo depigmenting activity of coenzyme Q10 through the down-regulation of α-MSH signaling pathways and induction of Nrf2/ARE-mediated antioxidant genes in UVA-irradiated skin keratinocytes. Biochemical Pharmacology (2019).

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