Sermorelin vs ipamorelin: both peptides make the pituitary gland release growth hormone, but through different receptors. Sermorelin is a copy of growth hormone-releasing hormone (GHRH), and ipamorelin mimics ghrelin, the “hunger hormone”.[1][2] Sermorelin was FDA-approved (as Geref) until it was discontinued in 2008; ipamorelin has never been approved, and FDA advisers voted 0 to 12 in 2024 against allowing it in traditional compounding.[3][4] Ipamorelin’s only published efficacy trial did not beat placebo.[5]
See the sermorelin and ipamorelin profiles, or browse our growth hormone peptides hub.
Sermorelin vs ipamorelin at a glance
| Sermorelin | Ipamorelin | |
|---|---|---|
| Mimics | GHRH (first 29 amino acids)[1] | Ghrelin; a 5-amino-acid peptide[2] |
| Receptor | GHRH receptor[1] | Ghrelin / growth hormone secretagogue receptor[2] |
| FDA history | Approved 1990 (diagnostic) and 1997 (children’s GH deficiency); discontinued 2008[3] | Never approved[4] |
| Main human evidence | Pediatric growth trials; small studies in older men[7][8] | One dosing study in healthy men; one failed surgery trial[6][5] |
| Half-life | Short; given daily in studies[1] | About 2 hours (IV)[6] |
| Compounding | Listed as compoundable by a pharmacy trade group[13] | FDA safety-risk list for outsourcing facilities[12] |
| Banned in sport | Yes[15] | Yes[15] |
How they work: two different switches
Growth hormone release is controlled by two main signals:
- GHRH, from the hypothalamus, tells the pituitary to make and release growth hormone. Sermorelin is the first 29 amino acids of GHRH, the shortest piece with full activity.[1]
- Ghrelin, mostly from the stomach, acts on a different receptor to trigger growth hormone release and hunger. Ipamorelin was developed in the 1990s to activate this receptor.[2]
Ipamorelin’s selling point was selectivity. In pigs, older ghrelin-type peptides (GHRP-6 and GHRP-2) also raised the stress hormones ACTH and cortisol, but ipamorelin did not, even at high doses.[2] That was shown in animals; human studies measured growth hormone only.[6] See GHRP-2 vs GHRP-6 vs hexarelin for those older peptides.
Because the two act on different receptors, they are often combined, like the CJC-1295 + ipamorelin pairing. CJC-1295 is a long-acting GHRH analog that raised growth hormone and IGF-1 for days in healthy adults.[16]
What the human research shows
Sermorelin
- Children with growth hormone deficiency: in 110 children treated nightly, growth rate rose from 4.1 to 8.0 cm a year at 6 months, and 74% were good responders.[7]
- Compared with growth hormone: in a 60-child study, growth hormone itself produced faster growth (14.6 cm a year versus about 9.2 on GHRH 1-29).[11]
- Older men: two weeks of 1 mg twice daily brought growth hormone and IGF-1 up to young-adult levels in 10 men.[8] Six weeks of 2 mg nightly in 11 men raised nighttime growth hormone without changing IGF-1, and improved two of six strength measures.[9]
Ipamorelin
- Healthy men: single IV infusions caused one burst of growth hormone, peaking about 40 minutes later and fading to negligible levels; the drug’s half-life was about 2 hours.[6]
- After bowel surgery: in a phase 2 trial of 114 patients, IV ipamorelin twice daily for up to 7 days did not significantly shorten the time to tolerating a solid meal (median 25.3 versus 32.6 hours; not statistically significant).[5]
- Fat and appetite: in mice, ipamorelin increased body fat and food intake, through effects not caused by growth hormone.[10] No human study has tested it for fat loss.
Side effects
- Sermorelin: the most commonly reported effects were temporary facial flushing and injection-site pain.[1] In one pediatric study, 39 of 40 children on GHRH 1-29 developed antibodies to it; these mostly disappeared after stopping.[11]
- Ipamorelin: human safety data come mainly from hospital patients receiving it by IV after surgery, where adverse events were common in both groups (87.5% on ipamorelin, 94.8% on placebo).[5] FDA has flagged a risk of immune reactions with compounded ipamorelin for some routes of use.[12]
- Both: a 2026 review of growth hormone peptides listed reported problems including raised prolactin or cortisol, appetite changes, blood sugar disturbances, fluid retention, joint and muscle aches and injection-site reactions.[17] Neither has long-term safety data in healthy adults.
Doses used in studies
No dose of either is currently approved, so the only reference points are research doses:
- Sermorelin: 30 mcg per kg once nightly in children with growth hormone deficiency;[1] 0.5 or 1 mg twice daily, or 2 mg nightly, in small studies of older men.[8][9]
- Ipamorelin: single IV infusions in healthy men, and 0.03 mg per kg IV twice daily after bowel surgery.[6][5] No under-the-skin dose has been tested in a published efficacy trial.
Doses promoted online come from sellers and forums, not these studies. A clinician must decide whether any use is appropriate.
FDA status and compounding
Sermorelin
- Approved as Geref in December 1990 for testing pituitary function and in September 1997 for idiopathic growth hormone deficiency in children; discontinued by its maker in 2008.[3]
- In 2013, FDA determined it was not withdrawn for safety or effectiveness reasons, which allows generic versions to reference it.[3]
- The Alliance for Pharmacy Compounding lists sermorelin among peptides that meet the legal criteria for compounding.[13]
Ipamorelin
- No FDA-approved drug contains it.[4]
- On October 29, 2024, FDA’s Pharmacy Compounding Advisory Committee voted 0 to 12, with one abstention, against placing ipamorelin on the list of bulk substances that traditional (503A) pharmacies may compound, citing a lack of safety and effectiveness data.[4]
- FDA’s current list of substances that may present significant safety risks places ipamorelin acetate in category 2 for outsourcing facilities (503B) since September 2023, citing immunogenicity risk.[12]
Sport: WADA prohibits both at all times, sermorelin as a GHRH analog and ipamorelin as a growth hormone secretagogue.[15]
This is general information, not legal advice. For an approved GHRH analog, see tesamorelin vs sermorelin.
