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Not FDA-approved
Bones & muscles
Ipamorelin
Ipamorelin is a ghrelin-mimicking peptide that raises growth hormone. Human data are limited to short studies, it is not FDA-approved, and sport bans it.
- Reviewed by
- William Maish, MD MBA MPH, Clinical Product Lead
- Published
- April 18, 2026
- Last updated
- October 5, 2026
Key takeaway
Ipamorelin is a synthetic peptide that mimics ghrelin to prompt the body to release more of its own growth hormone, and it is sold on the wellness and "research peptide" market. In a phase 2 trial of 114 bowel-resection patients (Beck, 2014), intravenous ipamorelin brought a median first tolerated meal at 25.3 hours versus 32.6 hours on placebo, a difference that was not significant (p = 0.15). Other human data show only that it raises growth hormone. As of 2026 it is not FDA-approved, it is not eligible for routine pharmacy compounding, and it is banned in sport.
What is ipamorelin?
Ipamorelin is an experimental five-amino acid peptide that acts as a ghrelin mimic, developed years ago under the code NNC 26-0161 but never marketed as a drug. It is sold through wellness and "research peptide" channels and promoted for recovery, body composition, and sleep, often paired with a GHRH analog such as CJC-1295 or sermorelin.
How does it work?
Ipamorelin activates the growth hormone secretagogue receptor, the same receptor the hunger hormone ghrelin1 uses, which triggers the pituitary to release growth hormone in pulses. In laboratory work it is described as relatively "selective," raising growth hormone with comparatively little effect on other hormones such as cortisol and prolactin. In conscious swine, it released GH without raising ACTH or cortisol2, while GHRP-6 and GHRP-2 raised both.
Because growth hormone and GHRH signaling act together, ghrelin-mimic peptides are often combined with GHRH analogs. No published human randomized controlled trial tests ipamorelin with CJC-1295 as of September 2026. The marketed benefits are extrapolated from this growth-hormone effect. This describes the proposed mechanism, separate from proven outcomes.
Is it FDA-approved?
No. Ipamorelin is not approved by the FDA and never reached market as a drug. Its compounding and sport status:
- Not eligible for routine 503A compounding, because its 503A nomination was withdrawn
- Still on FDA's 503B Category 2 list
- Prohibited at all times in sport under the WADA list, which covers growth hormone secretagogues including ipamorelin
What does the research show?
The human evidence is short pharmacology, not outcomes, and the supporting bone and gut data come from animal models:
| Study | Subjects | Finding |
| Dose-ranging study3, according to PubMed | Healthy men | Ipamorelin induced growth hormone release, a hormone-level finding rather than a clinical result; the study estimated a terminal half-life of 2 hours4 |
| Bone study5 | Rats with glucocorticoid-related bone changes | Supporting data on bone effects |
| Gut transit model6 | Rodent model of post-operative gut transit | Supporting data on gut effects |
| The one published phase 2 efficacy trial (Beck, 2014) | 114 patients analyzed7, adults after bowel resection, given intravenous ipamorelin or placebo | Median time to first tolerated meal was 25.3 versus 32.6 hours, p = 0.157, so it missed its primary endpoint; its secondary efficacy analyses showed no significant differences either |
Clinical development for post-operative ileus did not produce an approved product, and there are no controlled human trials supporting the marketed recovery or body-composition uses.
Sources: a pharmacodynamic study of ipamorelin (Gobburu et al., Pharmaceutical Research, 1999, DOI: 10.1023/a:10189551264023); animal studies on bone (Andersen et al., Growth Hormone & IGF Research, 2001, DOI: 10.1054/ghir.2001.02395) and gut transit (Venkova et al., Journal of Pharmacology and Experimental Therapeutics, 2009, DOI: 10.1124/jpet.108.1492116), all indexed on PubMed; and the WADA Prohibited List. This document is educational, is not medical advice or a health claim, and is not an offer to sell any product.