Silk Peptide — Frequently Asked Questions

Because the chains have to be long enough to interact with one another. Silk peptide retains chains of linked amino acids, typically hundreds to low thousands of daltons, which can deposit on a hair shaft or skin surface and entangle into a continuous breathable film. Fully hydrolysed amino acids are too small for that, and intact fibroin is insoluble.

It smooths the cuticle and reduces friction, which improves wet and dry combing, reduces breakage during styling and gives a perceptible increase in gloss. Because the peptide has affinity for keratin it deposits preferentially and is partly substantive, so some of the effect survives rinsing rather than washing straight off.

By stating the target range explicitly, because silk peptide and silk amino acids share the same INCI name, Hydrolyzed Silk, and the same CAS number. Ordering by name alone can produce either material. The specification should state molecular weight range alongside nitrogen content, appearance and solubility.

Yes, and it is most used there, since the film-forming and conditioning effects benefit from remaining on the hair or skin. It is water-soluble and non-tacky at normal use levels, which is why it suits leave-in conditioners and serums where a heavier protein would feel gummy.