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Ipamorelin

Medium Evidence

A selective growth hormone secretagogue studied for targeted GH release with fewer side effects than other GH peptides.

AliasesIPA+1 more

EvidenceMedium Evidence

Last Updated 2026-05-27

Reading Time 2 min

What It Is

Ipamorelin is a synthetic pentapeptide growth hormone secretagogue (GHS) that selectively stimulates growth hormone (GH) release from the anterior pituitary via the ghrelin/GHSR receptor pathway. It is distinguished from other GH secretagogues like GHRP-2 and GHRP-6 by its high selectivity — it stimulates GH release without significantly elevating cortisol, ACTH, prolactin, or aldosterone levels, giving it a cleaner hormonal profile. In clinical studies, ipamorelin demonstrated dose-dependent GH release with a favorable safety profile. A Phase II trial in post-surgical patients showed accelerated recovery of bowel function. When combined with CJC-1295 (no DAC), the two peptides are commonly studied together for their synergistic effect on restoring natural GH pulse patterns, with downstream effects on body composition, sleep quality, and recovery. Ipamorelin was placed on the FDA's Category 2 bulk drug substances list in October 2023, effectively prohibiting compounding pharmacies from preparing it. As of April 22, 2026, its regulatory status is nuanced: the Category 2 nomination was withdrawn for 503A compounding pharmacies, but it remains on the active Category 2 list for 503B outsourcing facilities. It is expected to be reviewed by the PCAC in the second session (before February 2027) for potential full reclassification. Ipamorelin is not FDA-approved for any indication and remains an investigational compound.

Also known as: IPA, NNC 26-0161

Regulatory Status

Mixed — Category 2 nomination withdrawn (503A); still Category 2 (503B)

Category 2 nomination withdrawn for 503A compounding pharmacies as of April 22, 2026, but remains on active Category 2 list for 503B outsourcing facilities. Expected PCAC review before February 2027 for potential full reclassification.

Effective: April 2026

View FDA Source

Why Researchers Study It

Ipamorelin is studied for its selective GH-releasing properties without the broad hormonal disruption seen with other secretagogues. Its clean cortisol and prolactin profile makes it attractive for research into age-related GH decline, post-surgical recovery, and body composition optimization. The combination with CJC-1295 is one of the most commonly studied GH-peptide stacks in the research community.

Proposed Mechanisms

Binds ghrelin receptor (GHSR) on pituitary somatotroph cells to stimulate pulsatile GH release
Selective GH stimulation without significant cortisol, ACTH, prolactin, or aldosterone elevation
Dose-dependent GH response that preserves natural circadian GH pulsatility
Synergistic with GHRH analogs (CJC-1295) to amplify GH pulse amplitude
Does not desensitize the GH axis as rapidly as non-selective secretagogues

Evidence Snapshot

Medium Evidence

Low

Medium

High

Study Type	Model	Outcome	Link
Phase II RCT (human)	Post-operative bowel recovery	Accelerated return of gastrointestinal motility in post-surgical patients	Source
Clinical (human)	GH secretion — dose-response study	Dose-dependent GH release without significant cortisol or prolactin elevation	Source