Endorphins mimic the effects of opiate drugs, which are pain perception and stress response. Alpha Endorphin is an endogenous opiate corresponding to the first 16 aa of the Beta endorphin sequence.Human: H-Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Leu-Val-Thr-OH or H-YGGFMTSEKSQTPLVT-OH