PeptideSciences is a leading provider of USA manufactured, research peptides. We have negotiated and partnered with WHO/GMP and ISO 9001:2008 approved manufacturers for the best prices available and for the highest quality and highest purity peptide products. TB-500 is a synthetic version of the naturally occurring peptide present in virtually all human and animal cells, Thymosin Beta-4. This potent peptide is a member of a ubiquitous family of 16 related molecules with a high conservation of sequence and localization in most tissues and circulating cells in the body.