Description
Ipamorelin is a synthetic pentapeptide that mimics ghrelin — the stomach-derived hormone that signals hunger and stimulates growth hormone release — by binding to the GHS-R1a receptor in the pituitary. It was specifically designed to stimulate growth hormone release with much greater selectivity than earlier compounds in its class, avoiding the stress hormone and cortisol responses that limited their research utility. Its clean selectivity profile has made it one of the most widely used reference compounds in GH research.
What the research has found
• Animal studies showed ipamorelin produced dose-dependent increases in plasma growth hormone levels after subcutaneous administration, with peak levels occurring 15–30 minutes post-injection. Crucially, this occurred without significant increases in cortisol, prolactin, or ACTH — the stress-related hormones that rise with older growth hormone secretagogues (Raun et al., 1998)
• Studies in young rats demonstrated that repeated ipamorelin administration produced measurable increases in body weight, bone growth (measured by tibial line width), and IGF-1 levels compared to untreated controls — confirming its downstream anabolic effects through the GH/IGF-1 axis (Raun et al., 1998)
• Research established that ipamorelin and GHRH (or CJC-1295) act through entirely different receptor systems, producing additive or synergistic GH release when combined. This has made ipamorelin a standard tool compound in research designs studying combined GH axis stimulation (Bowers, 1998)
• Binding studies confirmed ipamorelin has a very high affinity for GHS-R1a (Ki ~1 nM), making it a useful and consistent research tool for studying ghrelin receptor pharmacology (Bowers, 1998)
For research use only. Not intended for use in humans or animals.
References
Bowers, C. Y. (1998). https://pubmed.ncbi.nlm.nih.gov/9448082/
Raun, K., et al. (1998). https://pubmed.ncbi.nlm.nih.gov/9849822/
