Tesamorelin

Tesamorelin is human growth hormone releasing hormone (1-44) with a trans-3-hexenoyl group on the N-terminal tyrosine. That single modification protects the N-terminus from DPP-4 cleavage, which is the rate-limiting degradation step for native GHRH and the reason unmodified GHRH is impractical for anything but acute work. The result is a full GHRH receptor agonist that survives long enough to produce a measurable, sustained secretory response.

We file it under metabolic rather than growth because the bulk of the published work concerns visceral adipose tissue endpoints rather than growth axis endpoints — but the receptor pharmacology is straightforwardly GHRH-receptor mediated. It is a 44-residue peptide, long by secretagogue standards, and lots are screened for deletion sequences at the C-terminus where synthesis fidelity is weakest.