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Head-to-head comparison of Capromorelin and Ipamorelin — mechanism, side effects, legal status, and pricing.
Capromorelin is a non-peptide, orally active pyrazolinone-piperidine dipeptide-mimetic that functions as a growth hormone secretagogue receptor 1a (GHS-R1a) agonist, mimicking the endogenous hormone ghrelin. It is NOT approved for human use anywhere; a Pfizer Phase II trial in 395 older adults showed positive signals for lean body mass, body weight, and physical function but was terminated early and never advanced to approval. Capromorelin is FDA-approved as a veterinary drug (Entyce for dogs, Elura for cats) and is explicitly named on the WADA Prohibited List under S2 (growth hormone secretagogues), prohibited at all times in competitive sport.
Ipamorelin is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH2) originally developed by Novo Nordisk and later advanced by Helsinn/Nycomed. It is a selective ghrelin receptor agonist / growth hormone secretagogue (GHRP). Its defining feature versus older GHRPs (GHRP-2, GHRP-6, hexarelin) is that in preclinical and early clinical studies it raised GH without meaningfully increasing ACTH, cortisol, or prolactin. It is not FDA-approved for any indication; a Phase 2 trial for postoperative ileus failed to meet its primary endpoint and clinical development was discontinued. In the wellness/grey market it is sold as a research chemical and used off-label for anti-aging and body-composition goals despite no clinically validated human dose for those uses.
Capromorelin
Ipamorelin
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Legal Status
Mechanism
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Capromorelin
Ipamorelin
COA corpus from Disclosed Labs — independently tested batches only.
Capromorelin
No COA data yet.
Submit testing data →Ipamorelin
153
COAs
99.7%
Avg purity
17
Labs
Ipamorelin is among peptides under FDA review for the Category 1 (503A) list; if added, it would require a prescription to be compounded by registered 503A/503B pharmacies — not yet authorized. Capromorelin remains research-only. In April 2026 the FDA removed 12 peptides from Category 2, which does not place them on the Category 1 list or authorize compounding. The FDA's Pharmacy Compounding Advisory Committee is advisory and meets July 23–24, 2026 to review nominations and make recommendations to the FDA.
Capromorelin has human clinical trial data but is not an approved human drug. A Pfizer-sponsored Phase II trial randomized 395 adults aged 65–84 at risk of functional decline to oral capromorelin or placebo for up to 2 years (315 completed 6 months; 284 completed 12 months). The trial reported increased lean body mass (+1.4 vs 0.3 kg, P=0.001), body weight (+1.4 kg, P=0.006), improved tandem walk (P=0.02), and improved stair climb (P=0.04), concluding capromorelin "may improve body composition and physical function." The study was terminated early according to predetermined treatment effect criteria; no human product was ever approved. Preclinical studies in rats showed an ED50 <0.05 mg/kg IV for plasma GH elevation; in healthy Beagle dogs, oral capromorelin increased food consumption and body weight in a 4-day randomized, masked, placebo-controlled trial. In healthy cats, capromorelin altered glucose-metabolism parameters. In broiler chickens, it increased feed intake and body-weight gain.
Key references
The seminal preclinical characterization (Raun et al., 1998, PMID 9849822) established ipamorelin as the first GHRP-receptor agonist with GH-release selectivity comparable to GHRH, without raising ACTH or cortisol even at doses more than 200-fold above the ED50. Pharmacokinetic-pharmacodynamic modeling in healthy male volunteers (Gobburu et al., 1999, PMID 10496658) confirmed a roughly 2-hour half-life and dose-dependent GH response following IV infusion. The most advanced human study is Beck et al. (2014, PMID 25331030), a Phase 2, randomized, double-blind, placebo-controlled trial in 114 patients after bowel resection evaluating IV ipamorelin 0.03 mg/kg twice daily for postoperative ileus; the drug was well tolerated but did not separate from placebo on the primary endpoint (time to tolerance of solid food), and the sponsor (Helsinn/Nycomed) discontinued development. There are no completed registrational trials in adult GH deficiency, frailty, or body-composition indications. Ipamorelin is not FDA-approved for any indication. The 100–300 mcg dose range reflects community/compounding practice and is not clinically validated for anti-aging or body-composition use.
Capromorelin (Hormone) and Ipamorelin (Performance) are in different categories and target different biological pathways. This is a common pattern in multi-compound research protocols. Researchers should monitor the biomarkers from both profiles and watch for interactions listed in each compound’s contraindications. Consult a licensed healthcare provider before combining any research compounds.
This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.
Contraindications
Lab Testing
Key references