Keratin-based biomaterials have emerged as potential candidates for various biomedical and biotechnological applications due to their intrinsic biocompatibility, biodegradability, mechanical durability, and natural abundance. The objective of our study is to explore the feasibility and potential applications of keratin for promoting nitric oxide (NO) release. Herein, keratin was ?rst extracted from human hair and then modi?ed with iodoacetic acid to afford S-carboxymethyl keratin. The amino acid residues, isoelectric point, and molecular weight of keratin were quanti?ed with amino acid analyzer, zeta potential measurement, and SDS-PAGE method. Interestingly, human hair keratin was proved to be capable of promoting NO release from endogenous donor of S-nitrosoglutathione (GSNO) in the presence of glutathione.