sh-Octapeptide-28 SP is a single chain human peptide, produced synthetically to be identical to a portion of the protein, Alpha-Melanocyte-Stimulating Hormone, and consists of arginine, glycine, histidine, methionine, phenylalanine, tryptophan, tyrosine and valine. The parent protein contains a maximum of 26 amino acids which may contain disulfide bonds and/or glycosylation, and consists of the proper sequence of the 20 standard amino acids.