Naturally present in the body, collagen is the most abundant protein in the human body: it accounts for about 25% of the proteins recorded in the body. Produced by fibroblasts, it provides a mechanical resistance to stretching and a structure to many of the body's connective tissues, which is why collagen is found, among other things, in the skin, muscles, bones, ligaments, tendons, hair...
There exist 28 types of collagen each with different properties depending on where it is located, of which type I is the major component of the extracellular matrix of the dermis, representing 80 to 90% of the total collagen. It is characterised by three polypeptide chains organised in a helical manner, each composed of a thousand amino acids linked together by disulfide bridges to form patterns (called sequences). Glycine is the most represented amino acid, but it is also rich in proline and hydroxyproline.
Collagen holds significant importance for the skin. Present in the form of fibres, it ensures tissue regeneration, provides a high degree of elasticity, imparts flexibility and resilience, and acts as a binder between skin cells, helping to maintain its structure. The issue is that as the years pass, collagen synthesis slows down. This loss can begin around the age of 25, and the body can lose approximately 1% of collagen per year, and progressively up to 25% per year. Thus, by the age of 80, we have lost 75% of collagen compared to young adults. Moreover, over the years, collagen fibres become rigid, fragmented and disorganised.
These phenomena promote the appearance of wrinkles, loss of firmness and elasticity in tissues, and sagging of the skin. On the other hand, a lack of collagen in the skin results in an irregular skin texture: the skin loses its radiance and the complexion becomes less uniform. Unprotected exposure to UV rays, smoking, air pollution, not to mention the role of diet with glycation (the binding of sugars to collagen) leading to a stiffening of this protein, all contribute to this premature degradation of collagen.