Tesamorelin is a synthetic analogue of full-length human growth hormone-releasing hormone, GHRH(1-44) amide, modified with a trans-3-hexenoyl group on the N-terminal tyrosine. The acyl group sterically hinders dipeptidyl peptidase-4 cleavage at the Ala2–Asp3 bond, which is the principal route by which native GHRH is inactivated in plasma. Mechanistically it is a receptor agonist at the GHRH receptor on anterior pituitary somatotrophs — that is, an analogue of the hypothalamic releasing factor, not of growth hormone itself. The parent 44-residue sequence corresponds to mature human somatoliberin (UniProt P01286, residues 32–75), which is C-terminally amidated at Leu44.

Tesamorelin is a licensed medicine. It is marketed in the United States by Theratechnologies under the Egrifta name, with current FDA-labelled products EGRIFTA SV and EGRIFTA WR on file at DailyMed, indicated in HIV-associated lipodystrophy. Its registrational evidence base consists of two Phase III trials in that population; separately, investigator-initiated academic work has examined it in the context of hepatic fat content and in cognition studies in older adults.

An honest limitation: approval in one indication and one population does not transfer to any other. The controlled human evidence for tesamorelin is essentially confined to adults with HIV-associated lipodystrophy, and its long-term safety profile outside that setting has not been established. Separately, research-grade material is not the approved product — it is not manufactured, formulated, tested, or released to the standards of the licensed medicine, and no equivalence to Egrifta should be inferred from a shared CAS number.