Tesamorelin is a synthetic 44-amino-acid analog of growth hormone-releasing hormone (GHRH) with a stabilizing N-terminal hexenoyl modification that resists enzymatic degradation. It is the only GHRH-analog peptide approved by the FDA for any indication, originally for HIV-associated lipodystrophy under the brand name Egrifta. Documented research spans GH/IGF-1 axis stimulation, visceral adipose tissue biology, hepatic fat metabolism, and lipid profile modulation.

Ipamorelin is a synthetic pentapeptide developed in the late 1990s as a selective growth hormone secretagogue in the GHRP family. It binds the ghrelin receptor (GHSR1a) to stimulate pulsatile GH release without significant cortisol or prolactin elevation observed with earlier-generation secretagogues. Documented research spans pulsatile GH release pharmacology, longitudinal bone growth in animal models, and counteraction of glucocorticoid-induced bone loss.

The combination is a classical research-stack pairing: a GHRH analog (Tesamorelin) plus a GHRP-family secretagogue (Ipamorelin), each acting on a different point of the somatotrophic axis. Neither compound has been approved by the FDA for human use outside the original GHRH-research and HIV-associated lipodystrophy context. Both remain classified as research compounds outside that approved indication.