sh-Pentapeptide-50 SP is a single chain human peptide, produced synthetically to be identical to a portion of the protein, Pro-opiomelanocortin, and consists of arginine, glutamic acid, histidine, phenylalanine and tryptophan. The parent protein contains a maximum of 267 amino acids which may contain disulfide bonds and/or glycosylation, and consists of the proper sequence of the 20 standard amino acids.