Ipamorelin is a research peptide with no approved human indication — anywhere.

The short version

Ipamorelin is a lab-made peptide — a short chain of five amino acids — that tells the pituitary gland (a pea-sized gland under the brain) to release a pulse of growth hormone. It was built in the 1990s as the cleanest member of its class: it raises growth hormone without raising the stress hormone cortisol ^[1]. That selectivity is the whole reason it is interesting. What it is not is a medicine. No health authority anywhere has approved ipamorelin to treat anything, and the one published human trial — testing it after bowel surgery — did not work ^[3]. Almost everything sold online is a research chemical of unverified purity. People in research-use communities report deeper sleep and faster recovery; they also report flushing and hunger — and what they report is Ipamorelin effects you can read in full, all of it anecdotal rather than proven. This site is a plain-English digest of the published science and the regulatory paperwork. It does not sell anything and gives no dosing advice.

What ipamorelin actually is

Ipamorelin (sequence Aib-His-D-2-Nal-D-Phe-Lys-NH2; development code NNC 26-0161) is a synthetic pentapeptide — a five-unit peptide — discovered at Novo Nordisk in the 1990s ^[1]. It is a growth hormone secretagogue: a compound that prompts the pituitary to secrete growth hormone (GH). It works by switching on the ghrelin receptor (GHS-R1a) — the same receptor the body's own "hunger hormone" ghrelin uses — on the GH-producing cells of the pituitary ^[1].

What made ipamorelin notable in 1998 was its selectivity. Older peptides in the same family (GHRP-6, GHRP-2) released GH but also drove up cortisol and prolactin. In its founding study, ipamorelin released GH as potently as GHRP-6 in pigs (effective dose 2.3 nmol/kg versus 3.9 nmol/kg for GHRP-6) yet did not raise cortisol even at doses more than 200 times its GH-releasing dose ^[1]. It was, in the authors' own framing, the first highly GH-selective secretagogue.

A point this site returns to: ipamorelin is not the "CJC-1295 and ipamorelin" combination sold as a stack. That pairing adds a separate GHRH-analog peptide. This dossier is about ipamorelin alone.

The regulatory headline

Ipamorelin has never been approved as a drug by the U.S. Food and Drug Administration (FDA), the European Medicines Agency, or any other authority ^[3]. It reached human testing once: a Phase 2 trial in patients recovering from bowel surgery (NCT00672074, 114 adults). It missed its primary endpoint — median time to first tolerated meal was 25.3 hours on ipamorelin versus 32.6 hours on placebo, a difference that did not reach statistical significance (p=0.15) ^[3]. No further clinical program followed.

The regulatory picture tightened further in 2024. The FDA removed ipamorelin acetate from Category 2 of its interim Section 503A bulk-substances list and reviewed it at the October 29, 2024 Pharmacy Compounding Advisory Committee meeting; it is not an approved bulk substance for compounding ^[3]. Separately, ipamorelin is prohibited in sport at all times under the World Anti-Doping Agency's category S2, and accredited laboratories can detect it in urine down to sub-nanogram concentrations ^[7][8][9]. The full regulatory account is laid out on the is ipamorelin fda approved page.

What the studies measured

The published evidence is mostly preclinical, with a thin human layer. In healthy male volunteers given single intravenous doses, ipamorelin showed a terminal half-life of about 2 hours and produced a single GH pulse peaking roughly 40 minutes after dosing ^[2]. In adult female rats, subcutaneous ipamorelin dose-dependently increased the rate of long-bone growth — from 42 micrometres per day on vehicle to 52 micrometres per day at the highest dose — without measurably changing systemic IGF-1 ^[4]. The most recent in-vivo study, in ferrets in 2024, found that ipamorelin blunted chemotherapy-associated weight loss by about 24% but had no anti-nausea effect ^[5].

What is missing matters as much as what is present. There is no completed Phase 3 trial, no long-term human safety database, and no published safety characterization of the subcutaneous self-administration route that dominates real-world use ^[3]. A 28-day study of a different peptide in the same receptor class found dose-dependent heart-muscle damage in rats — a class-level signal that frames why chronic dosing warrants scrutiny ^[6]. The Ipamorelin research page walks through each study in full.