Ipamorelin
Performance, Muscle Building
In short
- A selective ghrelin receptor (GHS-R1a) agonist that stimulates pulsatile growth hormone release.
- Its distinguishing feature is selectivity: unlike GHRP-6 and GHRP-2 it produces little cortisol, prolactin, or appetite stimulation.
- Developed by Novo Nordisk and taken into human trials for post-operative ileus, then discontinued — it did not meet endpoints and was never approved.
- Prohibited at all times in sport under WADA class S2.
- Human pharmacokinetic detail is limited; a short half-life of roughly two hours is commonly cited.
Structure
How it works
Ipamorelin is a pentapeptide agonist at the growth hormone secretagogue receptor, the same receptor ghrelin acts on. Binding triggers GH release from the anterior pituitary in a pulse that mimics natural secretion rather than producing a sustained elevation.
Selectivity is the point. GHRP-6 and GHRP-2 also activate this receptor but spill over into ACTH and prolactin release; ipamorelin was designed to avoid that, which is why it is often described as the cleanest of the class.
What the research shows
Human trials confirmed dose-dependent GH release. The clinical programme targeted post-operative ileus and was discontinued after it failed to demonstrate benefit.
Effects on body composition, recovery, and sleep are reported anecdotally and have not been established in controlled human studies. Raising GH is a demonstrated effect; producing a desired outcome from that is a separate and unproven claim.
Dosing in the literature
Figures below are quoted from published studies, with the species or population they were measured in. They are records of what was studied, not recommendations.
| Studied in | Amount | Route | Source |
|---|---|---|---|
| Human — GH release studies, healthy volunteers | Dose-dependent GH response across microgram-per-kilogram intravenous ranges | intravenous | PubMed |
| Human — post-operative ileus programme | See trial records for the administered schedule | — | PubMed |
Commonly reported ranges
These are amounts people report using. They are not from any study, have not been evaluated for safety, and are reproduced here only because they circulate widely and are better seen alongside the evidence than instead of it.
| Reported by | Amount | Route |
|---|---|---|
| Commonly reported | 200–300 µg, one to three times daily | subcutaneous |
No published human pharmacokinetic study establishes a dose, interval, or duration for this compound. Community figures below have no trial behind them and are reports of practice, not evidence. Timing away from food is commonly described on the rationale that elevated insulin and glucose blunt GH release — that physiological relationship is real, though the practical significance for this compound is not quantified.
Handling and storage
Lyophilised powder, reconstituted with bacteriostatic water, refrigerated after mixing. Subcutaneous injection is the usual route.
Most reported protocols dose on an empty stomach and often before sleep, aligning with the natural nocturnal GH pulse.
Side effects
Reported effects are generally mild: injection-site reactions, headache, flushing, and transient light-headedness. Selectivity means the appetite stimulation and cortisol elevation typical of GHRP-6 are largely absent.
The class-level considerations for raising GH apply — water retention, joint discomfort, carpal tunnel symptoms, and reduced insulin sensitivity — and long-term human safety data does not exist for this compound.
Combinations
Most commonly paired with a GHRH analogue such as CJC-1295 or sermorelin, on the rationale that the two act through different receptors and produce a larger combined pulse than either alone. That synergy is described in the endocrinology literature for GHRH plus GHS generally.
Combining amplifies both the effect and the unknowns, and makes attribution impossible.
Research status
Characterised in the late 1990s and studied in humans for GH release and post-operative ileus. Development was discontinued. The literature is real but modest, and there is no long-term safety study.
Legal status
Not approved for human use in any jurisdiction. Development was abandoned before approval. Sold labelled for research use only; the FDA has placed several GH secretagogues in the category presenting significant risks for compounding.
WADA status
PROHIBITED AT ALL TIMES under WADA class S2 — growth hormone secretagogues, their releasing factors and mimetics are explicitly named. Any tested athlete should treat this as an anti-doping violation.
Conclusion
Ipamorelin is among the better-characterised research peptides here — a real molecule with a real clinical programme, which ended in failure to show benefit for its intended indication rather than in approval.
It reliably raises GH. Whether that produces anything you want is the part nobody has demonstrated.
Sources
Track your own Ipamorelin protocol
Peppers logs your doses, models your levels from this half-life, tracks your vials and tells you when you will run out. Free on iPhone.
Reference and educational information only. Not medical advice. Nothing here diagnoses, treats, or prescribes, and nothing here is a recommendation to use any compound. The compounds described are research chemicals and are not approved for human consumption. Legal and anti-doping status change — the review date above is when these claims were last checked. Talk to a qualified clinician about anything you intend to take.