Educational, research-use-only content. This article summarizes published scientific literature for informational purposes only and is not medical advice. The compounds discussed are supplied strictly for in-vitro laboratory research and are not approved for human or veterinary use.
What is ipamorelin?
Ipamorelin is a synthetic pentapeptide that acts on the growth-hormone-secretagogue (ghrelin) receptor. It was identified during a medicinal-chemistry program and described as the first selective growth-hormone secretagogue (Raun et al., 1998).
What the preclinical research examined
In rat pituitary cells and in rats and swine, ipamorelin released growth hormone with potency and efficacy comparable to GHRP-6. Crucially, unlike GHRP-6 and GHRP-2, ipamorelin did not meaningfully raise ACTH or cortisol — even at doses far above those needed for GH release — and did not affect FSH, LH, prolactin, or TSH. This selectivity for GH release is what distinguished it (Raun et al., 1998).
How it is thought to work
Ipamorelin mimics ghrelin at the GHS receptor to trigger GH release, a pathway complementary to GHRH analogs such as CJC-1295 — which is why the two are often studied together in the research literature.
The limits of the current evidence
- The foundational pharmacology is from cell and animal models; robust long-term human outcome data are limited.
- Ipamorelin is not an approved medicine and GH secretagogues are prohibited in sport by WADA.
References
According to PubMed:
- Raun K, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998. doi:10.1530/eje.0.1390552
