E910, also known as L-Cysteine, is an amino acid from hair that can come from animals or humans or be synthesized from coal tar. It is used in hair-care products and creams, in some bakery products, and in wound-healing formulations. Please check with the manufacturer to find out the source of Cysteine. It is likely that the manufacturer will be able to tell you. When you see an “E-number” like E910, it refers to an ingredient that has been approved by the European Union for use as a food additive.
