I noticed there seem to be a lot of hype about keratin hair products. Some shampoos and conditioners have, in the very first ingredients, "hydrolyzed keratin".
I noticed however that SB shampoo and conditioner do not have keratin in them, so I was wondering just out of curiosity if there is any point at all in adding keratin to shampoos and conditioners. Can it penetrate the hair or it must be endogenously produced?
Thanks!

Not much hydrolyzed keratin peptides will penetrate the skin. Adding copper to peptides helps peptide uptake into the skin.

Most or all of this is hype. The cosmetic industry needs new names of ingredients to throw around. But they have been hyping fake products for the last 10,000 years and are good at it.