Ipamorelin

Why scientists study it

• It raises pulses of growth hormone without pushing up ACTH or cortisol, unlike the older compounds GHRP-6 and GHRP-2.
• Its effects on bone and lean mass have been measured in rats and mice, including bone loss caused by steroid drugs called glucocorticoids.
• It leaves the blood fast, with a half-life of about 2 hours in a single-dose study of human volunteers.

Three studies to know

1998 · European Journal of Endocrinology

In rats and pigs, ipamorelin released GH about as strongly as GHRP-6, and doses that worked did not raise ACTH, cortisol or prolactin in the blood. Raun and colleagues called it the first GH secretagogue that was selective. Read the paper

2000 · Journal of Endocrinology

Repeated doses of ipamorelin or GHRP-6 raised bone mineral content in adult female rats. Svensson and colleagues put this down to GH and IGF-1 being stimulated for a long stretch. Read the paper

1999 · Pharmaceutical Research

This was the first published study of blood levels and GH response in healthy men. Gobburu and colleagues found that peak GH rose with dose and arrived within 15 to 45 minutes. The half-life of ipamorelin itself was about 2 hours. Read the paper

Safety and legal status

• The evidence is animal data, one single-dose study in human volunteers and one completed randomized phase 2 trial in bowel surgery patients. That trial missed its main goal. Ipamorelin was reported as well tolerated at the doses studied.
• It is not approved by the FDA, the EMA or the MHRA for any use. The World Anti-Doping Agency bans it at all times under class S2, which covers peptide hormones and growth factors.
• For laboratory research and test-tube use only. It is not meant for human use.