Thymosin α1 is a peptide fragment derived from prothymosin alpha, a protein that in humans is encoded by the PTMA gene. Thymosin α1 is believed to be a major component of Thymosin Fraction 5 responsible for the activity of that preparation in restoring immune function in animals lacking thymus glands. It was the first of the peptides from Thymosin Fraction 5 to be completely sequenced and synthesized. Unlike β thymosins, to which it is genetically and chemically unrelated, thymosin α1 is produced as a 28-amino acid fragment, from a longer, 113-amino acid precursor, prothymosin α. It has been found to enhance cell-mediated immunity in humans as well as experimental animals. MW: 3.1 kDa. Purity > 99%