Is Ipamorelin approved or legal?

Ipamorelin is not approved by the FDA (or other major regulators) for any human use. It reached Phase 2 trials for postoperative ileus but was not approved and development was discontinued. It is sold only as a research chemical, labeled research-use-only, and is not a medicine. It is not approved for human consumption.

What is Ipamorelin's half-life and how is it dosed?

Human PK studies report a terminal half-life of about 2 hours, with the GH pulse peaking roughly 40 minutes after a dose. There is no approved therapeutic dose. Community sources anecdotally describe ~100-300 mcg subcutaneously, 1-3 times daily, but this is research-reference only and not medical advice.

How does Ipamorelin work?

It activates the ghrelin receptor (GHS-R1a) on the pituitary, triggering selective, pulsatile release of growth hormone with little effect on cortisol or prolactin. The resulting GH rise can secondarily raise IGF-1.

Is Ipamorelin the same as CJC-1295?

No. CJC-1295 is a GHRH analog acting at the GHRH receptor (cAMP pathway), while ipamorelin is a ghrelin-receptor agonist (calcium pathway). They are mechanistically complementary, which is why they are often discussed together, though combined use is supported by anecdote rather than controlled human trials.

Does Ipamorelin have proven benefits for muscle or fat loss?

Not in robust human trials. Ipamorelin reliably raises GH in studies, but claims about lean mass, fat loss, recovery, and anti-aging are extrapolated from GH/IGF-1 physiology and animal data, not confirmed by controlled human outcome studies.

Hormonal

Ipamorelin

A selective ghrelin-receptor agonist that stimulates pulsatile GH release; human data limited and it is not an approved drug.

Last updated July 11, 2026

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Overview

Ipamorelin is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH2) first described by Raun and colleagues in 1998 as the first highly selective growth hormone (GH) secretagogue. It belongs to the growth-hormone-releasing peptide (GHRP) class and acts as an agonist at the growth hormone secretagogue receptor type 1a (GHS-R1a), the ghrelin receptor, on pituitary somatotrophs. Its main distinguishing feature is selectivity: in preclinical work it triggered GH release without the clinically meaningful rises in cortisol, ACTH, or prolactin seen with earlier GHRPs such as GHRP-6, and without the appetite stimulation associated with ghrelin agonism in some models. This made it attractive as a research tool for studying GH biology. Ipamorelin was originally developed by Novo Nordisk and later studied (by Helsinn) for postoperative ileus. It reached Phase 2 human trials but was not approved for any indication and development was discontinued. Today it is sold only as a research chemical and is widely discussed in fitness and longevity communities, frequently stacked with the GHRH analog CJC-1295. It is not approved by the FDA for human use. Claims around body composition, recovery, and anti-aging are largely extrapolated from GH physiology and animal data rather than confirmed by robust human outcome trials.

How it works

Ipamorelin binds and activates the GHS-R1a (ghrelin) receptor on anterior-pituitary somatotrophs. Receptor activation couples through Gq/phospholipase C, generating IP3 and mobilizing intracellular calcium, which drives GH secretion. This pathway is distinct from and complementary to GHRH, which signals via cAMP at the GHRH receptor; this mechanistic complementarity is the rationale for combining ipamorelin with GHRH analogs such as CJC-1295. Because it mimics endogenous ghrelin signaling, ipamorelin produces a pulsatile rather than continuous GH rise. Its defining preclinical property is selectivity for GH release with minimal effect on ACTH, cortisol, and prolactin.

Researched effects

Clinical Stimulates dose-dependent, pulsatile growth hormone release
Preclinical Selective GH release with little or no rise in cortisol, ACTH, or prolactin compared with older GHRPs
Preclinical Raises IGF-1 secondary to GH elevation
Anecdotal May support lean body composition, fat loss, and recovery (extrapolated from GH/IGF-1 physiology)
Anecdotal May improve sleep quality and well-being
Preclinical Accelerates gastrointestinal transit in a rodent postoperative ileus model

Evidence levels: Clinical (human trials) · Preclinical (animal/lab) · Anecdotal (community-reported).

Dosing reference

For research reference only — not a recommendation.

Clinical / studied dosing

No approved clinical dosing exists; ipamorelin is not a licensed drug. In investigational human studies it was given intravenously. The Phase 2 postoperative ileus proof-of-concept trial in bowel-resection patients used intravenous ipamorelin 0.03 mg/kg twice daily for up to 7 days; it was well tolerated but did not significantly improve the primary efficacy endpoint versus placebo. Human pharmacokinetic studies administered single IV infusions to characterize the GH response. There is no established therapeutic dose for body composition, anti-aging, or performance use.

Community-reported dosing (anecdotal)

ANECDOTAL / RESEARCH-REFERENCE ONLY - not medical advice and not an instruction to use. Community sources (e.g., r/Peptides, peptide guides) commonly describe subcutaneous use of roughly 100-300 mcg per dose, taken 1-3 times daily, often dosed before bed and/or fasted to coincide with natural GH pulses. Reported cycles run about 8-12 weeks followed by a washout. A frequently cited stack pairs ipamorelin (~200-300 mcg) with the GHRH analog CJC-1295 for purported additive GH release. These figures reflect unverified self-report, vary widely by source, and carry sourcing/purity risks; they are not validated by controlled human trials.

Half-life: ~2 hours (terminal half-life in human PK studies; GH pulse peaks ~40 min post-dose)
Routes: subcutaneous, intramuscular

Safety & side effects

Human safety data are limited and short-term. In trials ipamorelin was generally well tolerated, consistent with its selective profile (minimal cortisol/prolactin perturbation). Plausible and reported effects relate to GH/IGF-1 elevation and ghrelin signaling: water retention, transient numbness or tingling, headache, flushing or injection-site reactions, lightheadedness, and possible effects on insulin sensitivity/blood glucose with sustained GH elevation. Theoretical longer-term concerns from chronic GH/IGF-1 excess include edema, joint pain, carpal-tunnel-like symptoms, and a theoretical concern about promoting growth of existing tumors; these are not established for ipamorelin specifically. It is research-use-only, not FDA-approved, and product purity/identity from research suppliers is not guaranteed. People who are pregnant, breastfeeding, have cancer, or have endocrine disease should not use it; not medical advice.

Research summary

The strongest evidence for ipamorelin is mechanistic and preclinical. The foundational 1998 work by Raun et al. established it as a potent, selective GH secretagogue acting at the ghrelin/GHS-R1a receptor, releasing GH in vitro and in vivo without significant ACTH or cortisol release - the property that made it notable. Human pharmacokinetic-pharmacodynamic studies confirmed a short (~2 hour) half-life and a measurable GH response after dosing, supporting the mechanism in people. Clinical outcome evidence is weak. The most advanced human program targeted postoperative ileus; despite a clean hormonal and safety profile, ipamorelin did not significantly accelerate the primary recovery endpoint, and the compound was not advanced to approval. There are no robust, controlled human trials demonstrating the body-composition, anti-aging, recovery, or performance benefits widely claimed in consumer and community settings. Those benefits are inferred from GH/IGF-1 physiology and animal data. In summary, ipamorelin is a well-characterized, selective GH secretagogue with credible mechanism and reassuring short-term tolerability in limited human studies, but lacking proof of meaningful clinical benefit and lacking long-term safety data. Community dosing protocols are anecdotal and should be treated as research reference only, not medical guidance.

FAQ

Is Ipamorelin approved or legal?: Ipamorelin is not approved by the FDA (or other major regulators) for any human use. It reached Phase 2 trials for postoperative ileus but was not approved and development was discontinued. It is sold only as a research chemical, labeled research-use-only, and is not a medicine. It is not approved for human consumption.
What is Ipamorelin's half-life and how is it dosed?: Human PK studies report a terminal half-life of about 2 hours, with the GH pulse peaking roughly 40 minutes after a dose. There is no approved therapeutic dose. Community sources anecdotally describe ~100-300 mcg subcutaneously, 1-3 times daily, but this is research-reference only and not medical advice.
How does Ipamorelin work?: It activates the ghrelin receptor (GHS-R1a) on the pituitary, triggering selective, pulsatile release of growth hormone with little effect on cortisol or prolactin. The resulting GH rise can secondarily raise IGF-1.
Is Ipamorelin the same as CJC-1295?: No. CJC-1295 is a GHRH analog acting at the GHRH receptor (cAMP pathway), while ipamorelin is a ghrelin-receptor agonist (calcium pathway). They are mechanistically complementary, which is why they are often discussed together, though combined use is supported by anecdote rather than controlled human trials.
Does Ipamorelin have proven benefits for muscle or fat loss?: Not in robust human trials. Ipamorelin reliably raises GH in studies, but claims about lean mass, fat loss, recovery, and anti-aging are extrapolated from GH/IGF-1 physiology and animal data, not confirmed by controlled human outcome studies.

References

All content is for research and educational use only and is not medical advice. Products are sold for laboratory research only and are not for human consumption.