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Also: NNC 26-0161 · Ipa · ipamorelin peptide · CJC-1295/Ipamorelin · ipamorelen · ipamoralin · ipamorlin · ipramorelin · ibramorelin
Four separate measurements, never averaged. Independent evidence counts only studies with no sponsor attached. Methodology version v2.0-2026-10 · how we grade evidence
Not approved by any regulator, anywhere, for any indication, and development was discontinued. Ipamorelin acetate is the only compound in this cluster still listed in FDA Category 2 — bulk drug substances for use in compounding that may present significant safety risks — under the 503B policy, added 29 September 2023 and still listed as of April 2026.
Claims — stated as claims — include increased growth hormone without raising cortisol or prolactin, lean muscle gain, fat loss, improved sleep, improved recovery and "anti-aging." It is most often sold blended with CJC-1295 or sermorelin, and marketed by medical spas and wellness clinics in injectable, nasal and oral forms.
Two human studies exist. One is a healthy-volunteer pharmacokinetic study with no efficacy endpoint; the other is a Phase 2 efficacy trial that failed. The 48-man dose-escalation study established that intravenous ipamorelin releases growth hormone, and FDA notes it reported no effectiveness data for growth hormone deficiency and did not report adverse events. The Phase 2 trial in postoperative ileus, 114 patients randomised, missed its endpoint — median time to first tolerated meal 25.3 hours versus 32.6 hours with placebo, not statistically significant — and the programme was then discontinued. The 2026 sports-medicine scoping review found three studies in its scope, all animal, none human, and states that no human musculoskeletal trials exist.
No human study exists for the subcutaneous route, which is the route in which it is almost universally sold and used. Both human studies were intravenous. FDA found nonclinical data too limited to assess safety — no acute toxicity, repeat-dose toxicity, genotoxicity or carcinogenicity studies in any species — and no reproductive safety data. It raised one concern that gets little attention in marketing: ipamorelin "may have reinforcing or addictive properties through ghrelin receptor activity in reward pathways." A formulation-plausibility finding is also worth recording: FDA calculated the free base to be only slightly soluble in water, at 0.0032 mg/mL, and questioned whether the nominated concentration is even achievable. In the grey-market survey ipamorelin was comparatively one of the better performers, with 34.2% of samples meeting a manufactured-drug benchmark — second highest of fourteen peptides, which is a statement about the other thirteen as much as about this one.
At a glance
Selective agonism of the ghrelin receptor (GHS-R1a) on pituitary somatotrophs, stimulating growth hormone release with claimed selectivity over ACTH, cortisol and prolactin release. Animal work in rats showed accelerated colonic transit and gastric emptying in postoperative ileus models, reduced visceral hypersensitivity, and a half-life of about 27 minutes with 60 to 80% excreted unchanged. The growth-hormone-releasing effect is confirmed in humans by a randomised, placebo-controlled intravenous dose-escalation study in 48 healthy men. No clinical benefit is confirmed in humans. As with CJC-1295, those are two different claims and only the first is supported.
Dated determinations, each flagged for whether it is final and whether it covers safety only. A safety review is not an efficacy finding, and most reporting in this category conflates the two.
Recorded as stated in the research package. No document, scheduling instrument or date was retrievable, so this row carries the fact and nothing more.
FDA’s page, content current as of 22 April 2026, still lists ipamorelin acetate under the 503B policy, while BPC-157, TB-500, CJC-1295, AOD-9604 and MOTs-C appear only in the "nominated but withdrawn" table and 5-amino-1MQ and tesamorelin do not appear at all.
Named in the 2026 list at S2.2.4; FDA’s 2024 document cites the then-current numbering as S2.4, which is the same prohibition under earlier section numbers.
Votes on 29 October 2024: ipamorelin free base 0 yes / 12 no / 1 abstain; ipamorelin acetate 0 yes / 12 no / 1 abstain. Members voting no cited the lack of safety and efficacy information for the two nominated indications. It is not on the 503A Bulks List.
FDA states nonclinical data were too limited to assess safety: no acute toxicity, repeat-dose toxicity, genotoxicity or carcinogenicity studies in any species. No human study exists for the subcutaneous route, the route in which the compound is almost universally sold; both human studies used intravenous administration. FDA raised a concern that gets little attention in marketing — ipamorelin "may have reinforcing or addictive properties through ghrelin receptor activity in reward pathways" — and noted that ghrelin and a ghrelin antagonist affected fertility and embryofetal development in mice while it is unknown whether ipamorelin does, so there are no reproductive safety data. FAERS held two non-serious events (headache and increased lacrimation with a nasal spray; arthralgia with an ipamorelin-sermorelin injection) and CAERS none. Immunogenicity cannot be ruled out; no certificate of analysis was provided for the free base and the acetate certificate lacked testing for impurities, aggregates and endotoxins. FDA also calculated the free base to be only slightly soluble in water, at 0.0032 mg/mL, and questioned whether the nominated concentration is achievable at all.
Added 29 September 2023 as one of the 19 substances. A safety-concern listing, which says nothing about whether it works.
Recorded from OPSS guidance updated 7 March 2022; no retrievable document URL, so the source key is null rather than an invented identifier. It is not a lawful dietary supplement ingredient and is sold online labelled "research use only."
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