Ipamorelin
Ipamorelin, a peptide. Selective GHSR-1a (ghrelin receptor) agonist — drives pulsatile GH release without raising ACTH, cortisol, or… Subcutaneous half-life 2 h.
Selective GHSR-1a (ghrelin receptor) agonist — drives pulsatile GH release without raising ACTH, cortisol, or prolactin. Cleaner receptor specificity than GHRP-2/GHRP-6/hexarelin. Short plasma t½ mandates divided dosing.
PK: Gobburu 1999 (PMID:10496658), 40 healthy male volunteers across five dose levels, verbatim "a short terminal half-life of 2 hours". ROUTE CAVEAT: that study used a 15-minute IV infusion, not subcutaneous dosing. V 4.9 L dropped 2026-09-06 — the paper states "a volume of distribution at steady-state of 0.22 L/kg", about 15 L at 70 kg, so the stored value was roughly threefold too small and would require a 22 kg subject. F 0.75 dropped: an IV study cannot yield a bioavailability, and the only figure for this peptide in any species is roughly 20% INTRANASAL in rat (PMID:9879640). Human ipamorelin PK does exist, contrary to an earlier note that conflated this trial with the rat pharmacology paper.
Pharmacokinetics
- Subcutaneous — t½ 2 h
Related compounds
- GHRP-2 — synergistic
- Sermorelin — synergistic
- MK-677 — synergistic
Sources: PMID:9849822, PMID:10496658