Sericin is one of two proteins that make up silk. Fibroin forms the structural fibre, and sericin is the sticky protein coating that binds the fibres together in a cocoon.
A byproduct with a second life
In silk manufacturing, sericin is removed and discarded during degumming, historically as waste. Its use in cosmetics repurposes a byproduct of an existing industry rather than creating new demand.
How it works
Hydrolysed, meaning broken into smaller peptide fragments, sericin becomes water-soluble and able to interact with skin.
It is strongly hydrophilic, holding water at the surface and forming a light, flexible film that reduces water loss. Its amino acid profile is notably rich in serine, an amino acid also present in the skin's own natural moisturising factor, which is the basis of its compatibility claim.
Research has also reported antioxidant activity and effects on skin elasticity, though studies are limited in number and often small.
What hydrolysed proteins do and don't do
A general point worth understanding across the category. Hydrolysed proteins, whether silk, wheat, rice or collagen, work by sitting on the surface, binding water and forming a film. They do not become the equivalent protein in your skin. Applied silk protein does not become silk in your dermis, any more than applied collagen becomes collagen.
The effects are real and they are surface effects.
Not vegan
Sericin is derived from silkworm cocoons. Conventional silk production involves killing the pupae, so sericin is an animal-derived ingredient. Worth knowing if that matters to you.
