Beneficial active ingredient combinations to use with collagen?

In cosmetic care, collagen is very often combined with hyaluronic acid, a molecule prized for its hydrating properties. These active ingredients are naturally associated in the dermis, which is rich in connective tissue. This tissue is characterised by its abundant extracellular matrix, composed mainly of protein fibres, including collagen, and glycosaminoglycans (hyaluronic acid among others). Together, they form a compressible gel that retains water like a sponge, also ensuring the maintenance of the skin's structure.

In cosmetic formulation, these two active ingredients are used synergistically to provide hydration to the skin or hair. Indeed, collagen works by forming a thin film on the surface of the epidermis, thus protecting the epidermis and skin tissues from dehydration. Hyaluronic acid acts similarly, with its strong hygroscopic properties allowing it to retain up to 1000 times its weight in water. Together, collagen and hyaluronic acid make a good duo for protecting the skin, hydrating it, and preventing dehydration fine lines.

Note : Similarly, collagen can be combined with polyglutamic acid. This lesser-known active ingredient is just as effective, if not more so, than hyaluronic acid. Once applied, it traps up to 5000 times its weight in water, ensuring long-lasting hydration for the skin.

Also popular in the cosmetic sphere, vitamin C is a powerful antioxidant. By donating an electron to free radicals, it stabilises them and reduces oxidative stress in skin cells. Studies have shown that hydrolysed collagen, in addition to its hydrating properties, possesses anti-radical properties. These, however, depend on the size of the active ingredient: the lower the molecular weight of the peptides, the better their ability to donate an electron. By combating oxidative stress, the collagen/vitamin C combination prevents the degradation of endogenous protein fibres, skin sagging, and the appearance of sunspots.

If these two molecules are often combined, it is also because they can stimulate the synthesis of endogenous collagen. Indeed, it has been shown that peptides derived from hydrolysed collagen stimulate the proliferation and activity of fibroblasts, the cells responsible for collagen production. Vitamin C, on the other hand, serves as a cofactor for prolyl and lysyl hydroxylase, key enzymes that cross-link and stabilise collagen fibres. Vitamin C also directly activates transcription factors involved in collagen synthesis and stabilises procollagen messenger RNA, regulating the synthesis of type I and III collagen.

Biotin is a B vitamin essential for the proper functioning of the body. It contributes to the formation of skin cell membranes and the maintenance of the structure of keratin found in hair and nails. A deficiency in biotin can cause various issues, including alopecia or significant nail fragility. To address this, biotin treatments are offered, sometimes combined with collagen supplementation. Several studies have investigated the effects of these active ingredients when taken orally and have shown that they can help to thicken hair fibres. Shampoos containing collagen and biotin are also available, but their effectiveness seems limited due to the difficulty biotin has in penetrating the skin barrier.

Collagen and biotin treatments also appear to offer benefits for the skin. A recent study was conducted with 72 women divided into two groups who, for 12 weeks, took either a daily placebo or a vial containing 2.5 g of collagen peptides, biotin, acerola extract, vitamins C and E, and zinc. The researchers observed that the supplementation significantly increased skin hydration and elasticity, while the placebo had no effect. It is worth noting, however, that the dietary supplement contained more than just collagen and biotin.

The association between collagen and vitamin E is relatively similar to that of collagen and vitamin C. Indeed, vitamin E is also widely used for its antioxidant properties, allowing it to protect various cells in the body from oxidative stress induced by external aggressions such as the sun, pollution, or tobacco. Dietary supplements based on collagen and vitamin E have thus emerged in the nutricosmetics market, aiming to prevent skin sagging.

Regarding clinical studies that have focused on the effects of such supplementation on the skin, they are relatively few. However, we can mention the previously cited study conducted with 72 participants. This study shows an improvement in skin quality following a 12-week intake of a dietary supplement containing collagen, vitamin E, and other compounds. Nevertheless, it is again important to keep in mind that it is not only the effects of the collagen/vitamin E combination that were evaluated, but those of all the active ingredients present in the dietary supplement.

Just like collagen, elastin is synthesized by the fibroblasts in the dermis. These two proteins are closely associated in the extracellular matrix and contribute to the organization of tissues, with elastin's role being more specifically to allow the skin to retain its shape, even after stretching. However, cosmetic products based on elastin are quite rare, as this protein is more often incorporated into dietary supplements, where it can be mixed with collagen.

A study conducted with mice has demonstrated that supplementation with collagen peptides and elastin peptides can increase the levels of collagen, elastin, and hyaluronic acid in animal skin. It appears that these effects are due to the modulation of the expression of seven factors related to the synthesis of collagen and elastin, including IGF-1, LOX, SMAD2, JNK, SP1, TβRII, and TGF-β. However, this is only a single study, conducted with an animal model. More research would be necessary to conclude that supplementation with collagen and elastin can slow down skin aging in humans. Nevertheless, this is an encouraging avenue.

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