What it is
Sericin is the gummy, water-soluble protein that coats the fibroin fibers in silkworm (Bombyx mori) cocoons and binds them together. In cosmetics it is used as a film former and skin-conditioning agent that can leave a smooth feel and help retain moisture at the skin surface. It is a supporting protein ingredient rather than a UV filter.
Safety & warnings
Sericin is generally well tolerated in cosmetic use. Because it is a silk-derived protein, individuals with known silk allergy should be cautious, as protein components can occasionally provoke sensitization. It is not associated with comedogenicity in typical use.
Origin & sourcing
Animal-derived; recovered from silkworm cocoons, often as a byproduct of silk processing where sericin is separated from the fibroin silk fiber.
History
Sericin was long treated as a waste material removed during silk degumming before being recovered and adopted as a functional ingredient in cosmetics and other applications.
Questions everyone asks
What is sericin made from?
Sericin is a protein obtained from silkworm cocoons, where it acts as the natural glue holding the silk fibers together. It is often recovered during silk processing.
What does sericin do in a sunscreen?
It works as a film former and skin-conditioning agent, helping create a smooth surface feel and support hydration. It does not filter UV light.