Undecylenoylphenylalanine, also known as acylbenamide, is a melanogenic hormone (α-MSH) receptor antagonist that acts on the biochemical reactions at various stages of melanin formation triggered by α-MSH, intercepting melanin. Generates signals to control the combination of α-MSH (melanocyte stimulating hormone) and melanin production factors, effectively inhibiting the activity of tyrosinase, thereby inhibiting the formation of melanin. Mainly used in cosmetics as a whitening agent.