Thymalin

A polypeptide fraction (<10 kDa, CAS 79621-14-0) isolated from calf thymus by acid extraction and fractional precipitation, developed in the Soviet Union under Vladimir Khavinson and Vyacheslav Morozov. Contains a mixture of short peptides with immunomodulatory activity on T-cell differentiation and maturation. Registered in Russia since 1982 and still used clinically for immunodeficiency, post-surgical immune support, and infectious disease adjunct therapy; the synthetic dipeptide Thymogen (Glu-Trp) was subsequently developed to replicate its activity with a defined structure. Not FDA-approved.