Quick facts
- Class
- Growth-hormone secretagogue (GHRP / ghrelin mimetic)
- Studied for
- GH release, recovery, body composition
- Notable trait
- Selective — minimal cortisol/prolactin rise in studies
- Approval
- Not FDA-approved; banned by WADA
- Class
- Growth hormone secretagogue (ghrelin/GHS-R agonist)
- Approval
- Not approved for human use (research chemical)
- Anti-doping
- Prohibited at all times (WADA category S2)
- Selectivity
- Minimal cortisol/prolactin stimulation
Key takeaways
- Ipamorelin is a selective growth hormone secretagogue that mimics ghrelin to stimulate GH release from the pituitary.
- It is considered one of the most selective GH secretagogues, producing little to no rise in cortisol or prolactin at typical research doses.
- It is a research chemical — not approved by the FDA or any major regulator for human therapeutic use.
- Like all GH secretagogues, it is banned in sport at all times under the WADA Prohibited List.
- Human evidence is limited; most data come from preclinical studies and early-phase research.
Overview
Ipamorelin is a synthetic pentapeptide that belongs to a class of compounds known as growth hormone secretagogues. It mimics the action of ghrelin, the body's natural hunger-and-growth-signaling hormone, to prompt the pituitary gland to release stored growth hormone (GH). It was originally developed in the 1990s as a research tool to study the GH axis.
Unlike pharmaceutical GH itself, ipamorelin does not introduce growth hormone directly into the body. Instead it stimulates the body's own pulsatile release. It is frequently grouped with peptides such as GHRP-6 and hexarelin, but it is noted for being highly selective in laboratory studies.
Importantly, ipamorelin is not an approved drug in the United States, Europe, or other major markets. It is sold and circulated as a research chemical, meaning it has not passed the clinical trials required for human therapeutic use. It is also prohibited in sport by the World Anti-Doping Agency (WADA).
How it works
Ipamorelin binds to the growth hormone secretagogue receptor (GHS-R1a), the same receptor activated by the natural hormone ghrelin. When this receptor is engaged on cells of the anterior pituitary, it triggers an intracellular signaling cascade that causes the release of growth hormone into the bloodstream.
What distinguishes ipamorelin from some earlier secretagogues is its reported selectivity. In preclinical research it stimulated GH release with comparatively little effect on cortisol and prolactin, two hormones that are often elevated by less selective compounds. This selectivity is one reason it became a popular tool for studying the GH axis in isolation.
The downstream effect of increased GH is a rise in insulin-like growth factor 1 (IGF-1), which is produced largely by the liver and mediates many of GH's tissue-building effects. Because ipamorelin works by amplifying the body's own GH pulses rather than overriding them, its action is generally described as more physiological than direct GH injection, though this has not been validated through rigorous human trials.
Research & evidence
Most of what is known about ipamorelin comes from preclinical animal studies and early-stage pharmacological research rather than large, controlled human trials. These studies established its receptor activity and its relative selectivity for GH release, which is why it remains a reference compound in laboratory settings.
There has been some interest in GH secretagogues for conditions such as muscle wasting and postoperative recovery, but ipamorelin specifically has not been carried through the full clinical development pathway. Claims that it improves body composition, sleep, recovery, or anti-aging outcomes in humans are not supported by robust published evidence.
It is worth distinguishing ipamorelin from related secretagogues that did enter clinical programs. The absence of completed human efficacy and safety trials means that long-term effects, optimal use, and risk profile in people remain genuinely unknown. Consumers should treat marketing statements with skepticism, since the supporting science is thin.
Safety & legal status
Because ipamorelin has not undergone formal clinical safety evaluation in humans, its full side-effect profile is not well characterized. Theoretical and reported concerns associated with GH secretagogues include headache, flushing, water retention, changes in blood sugar regulation, and effects tied to elevated GH and IGF-1 over time. Sustained elevation of these hormones is a particular concern because of potential links to tissue overgrowth.
From a legal standpoint, ipamorelin is not approved by the FDA or comparable regulators for human use. Products sold online are typically labeled for research use only and are not manufactured to pharmaceutical quality standards, so purity and dosing accuracy cannot be assured.
Ipamorelin is on the WADA Prohibited List as a growth hormone secretagogue, meaning competitive athletes who use it risk sanctions. Anyone considering it should be aware that they are using an unregulated substance outside any approved medical framework, and should consult a qualified healthcare professional rather than self-experiment.
Frequently asked questions
What is ipamorelin?
Ipamorelin is a synthetic peptide that acts as a selective growth hormone secretagogue, binding the ghrelin receptor to trigger pulsatile GH release. It is used as a research compound and is not an approved medicine.
How is ipamorelin different from other GHRPs?
Compared with GHRP-6 and GHRP-2, ipamorelin is more selective for GH release and causes little to no increase in cortisol, prolactin, or appetite. This selectivity is its most frequently cited distinguishing feature.
Is ipamorelin approved by the FDA?
No. Ipamorelin has not been approved by the FDA or other major regulators for any therapeutic indication and is sold only as a research chemical.
Is ipamorelin banned in sport?
Yes. Growth hormone secretagogues including ipamorelin are prohibited at all times under the World Anti-Doping Agency's Prohibited List.
Is ipamorelin safe?
Its long-term safety in humans has not been established because it has not undergone the full clinical trial process required for approval. Reported research-context effects are limited and uncertainties remain.
References
Each source links to its original record — peer-reviewed studies, regulator pages, or reference texts, labelled by type. We summarize findings neutrally; a citation is a reference, not an endorsement, and not a claim that its authors reviewed this page.
- Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998. Peer-reviewed study
- Sinha DK, Balasubramanian A, Tatem AJ, et al. Beyond the androgen receptor: growth hormone secretagogues in the management of body composition in hypogonadal males. Transl Androl Urol. 2020. Peer-reviewed study
- Johansen PB, Nowak J, Skjaerbaek C, et al. Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats. Growth Horm IGF Res. 1999. Peer-reviewed study
- Lu Z, Ngan MP, Liu JYH, et al. The growth hormone secretagogue receptor 1a agonists, anamorelin and ipamorelin, inhibit cisplatin-induced weight loss in ferrets: Anamorelin also exhibits anti-emetic effects via a central mechanism. Physiol Behav. 2024. Peer-reviewed study
- Gouda M, Ganesh CB. The influence of ghrelin agonist ipamorelin acetate on the hypothalamic-pituitary-testicular axis in a cichlid fish, Oreochromis mossambicus. Anim Reprod Sci. 2024. Peer-reviewed study
- Gobburu JV, Agersø H, Jusko WJ, et al. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharm Res. 1999. Peer-reviewed study