Ipamorelin vs Somatropin (rhGH)
Sold for anti-aging, fat loss and muscle. It does raise growth hormone in people, but the one outcome trial, in 117 bowel surgery patients, did not work. It is lab-made growth hormone, approved for children and adults who lack it. It works for that, but anti-ageing clinics also sell it to healthy adults, and the labels do not back that.
Somatropin (rhGH) has the stronger evidence, grade A (strong human evidence) against grade C for Ipamorelin. Ipamorelin: Not approved. Somatropin (rhGH): FDA approved.
Evidence
CAnimal and cell studies
AStrong human evidence
Human studies cited
Animal or cell studies cited
Why the grade
For the anti-aging and body-composition use ipamorelin is sold for, no human trial exists. The human data are a 40-volunteer dose-escalation pharmacokinetic study showing a single growth hormone pulse, a 114-patient randomised phase 2 trial in post-operative ileus that found no benefit, and a comparative hormone study of related peptides. The selectivity claim comes from rats and swine.
The approved indications rest on four decades of randomized and controlled trials summarized in each product's label, including placebo-controlled trials in adult deficiency and growth velocity trials in children; the Norditropin label alone covers pediatric and adult deficiency, Turner syndrome, Noonan syndrome, Prader-Willi syndrome, small-for-gestational-age short stature and idiopathic short stature. Evidence for the uses it is sold for off-label, anti-aging and body composition in healthy adults, is a separate and much weaker question not covered by these citations.
FDA
Not approved
Ipamorelin is not approved by the FDA for any use and is sold online as a research chemical; its development for post-operative ileus was abandoned after a negative phase 2 trial. In 2023 the FDA placed it in Category 2 of its compounding lists, the category for substances with significant safety risks, and it remains there for outsourcing facilities (503B) although the nominations for pharmacy compounding (503A) were withdrawn in 2024. In October 2024 the Pharmacy Compounding Advisory Committee voted 12 to 0, with one abstention, against adding it to the 503A bulks list.
FDA approved
Somatropin, recombinant human growth hormone, has been FDA-approved since Humatrope in 1987 and is sold under several brands including Norditropin, Genotropin, Omnitrope and Zomacton, for growth hormone deficiency in children and adults and for a set of specific growth disorders. Two long-standing brands have left the market: Genentech discontinued Nutropin in 2024 and Lilly is ending Humatrope distribution at the end of 2026. Use for anti-aging or athletic performance is not an approved indication.
Sold for
Ipamorelin is sold as the cleanest growth hormone secretagogue, for anti-aging, fat loss and muscle, usually paired with CJC-1295.
Growth hormone is sold by anti-aging clinics and on the black market as the master hormone for youth, muscle and fat loss, well beyond the deficiency states it is approved to treat.
Studies say
Ipamorelin releases growth hormone in humans without the cortisol rise seen with GHRP-2 and GHRP-6, but the only outcome trial, in bowel surgery patients, was negative, and no study has measured body composition or aging, so the grade is C.
Somatropin reliably restores growth in children who lack growth hormone and improves body composition in deficient adults, which is what it is approved for; the labels do not support use in healthy adults, and the market is shifting toward weekly long-acting versions as older daily brands exit.
Class
GHRP / ghrelin receptor agonist
Growth hormone
Route
Injection
Injection