Why you shouldn't buy collagen shampoo?

The reason lies in the very nature of collagen and the structure of hair.

The size of the collagen molecule and the structure of hair. Collagen is a large fibrous protein composed of long polypeptide chains twisted into a triple helix.

The collagen molecule is too large to penetrate the hair cuticle and integrate into the keratin structure of the cortex.

Hair, unlike living tissues, does not have active blood supply or metabolism — its shaft is completely keratinized and is essentially "dead." Therefore, there can be no biochemical "integration" from the outside.

What collagen actually does in shampoo. In shampoos, collagen is either used in a hydrolyzed form (collagen hydrolysate) or as a film-forming agent.

When applied to hair, hydrolyzed proteins can:

• coat the hair cuticle with a thin layer, filling in micro-damages;
• temporarily reduce the roughness of the hair surface, making it smoother and shinier;
• retain moisture on the surface due to the film-forming effect, creating a feeling of "fullness" and elasticity.

Why the effect is temporary. These changes are purely cosmetic. After rinsing or during the next wash, the protective film is removed, and the hair returns to its original state.

Restoration of the damaged shaft is only possible mechanically (by cutting off the damaged part) or by preventing new damage (heat protection, reducing aggressive chemical exposure).

Where collagen actually works. To improve the strength and structure of hair, collagen must be synthesized in the body — from amino acids obtained from food or supplements. Hair follicles use these amino acids to build keratin and binding structures. Here, nutrients (proteins, vitamin C, copper, sulfur-containing amino acids) work, not external application.