The cleanest growth hormone pulse
A selective ghrelin receptor agonist that prompts GH release without cortisol or prolactin effects.
Educational content. This page describes Ipamorelin for informational purposes only and is not medical advice, diagnosis, or treatment. Consult a licensed provider before starting, stopping, or modifying any therapy.
Ipamorelin is a synthetic pentapeptide that functions as a selective growth hormone secretagogue (GHS). Developed by Novo Nordisk in the late 1990s, it was the first GHS identified to stimulate GH release without significantly affecting cortisol, prolactin, or ACTH.
Unlike GHRP-2 and GHRP-6 which increase appetite and elevate cortisol, ipamorelin provides a clean GH pulse, making it the preferred GHS for anti-aging, body composition, and recovery applications.
Ipamorelin binds to the ghrelin receptor (GHS-R1a) on pituitary somatotrophs, triggering pulsatile GH release that mimics natural secretion patterns. Pulsatile release maintains receptor sensitivity, unlike continuous exogenous GH.
Its selectivity comes from its specific binding profile — it potently activates GHS receptors on somatotrophs without stimulating corticotrophs or lactotrophs.
GH then exerts effects directly and through IGF-1: increased lipolysis, enhanced protein synthesis, improved collagen production, better sleep, and accelerated tissue repair. Often paired with CJC-1295 for synergistic effects.
The cleanest growth hormone pulse
Ipamorelin selectively binds GHS-R1a on pituitary somatotrophs, triggering pulsatile GH release through PLC/IP3/calcium signaling without activating corticotroph or lactotroph cells — stimulating downstream GH/IGF-1 effects including lipolysis, protein synthesis, and bone mineralization while maintaining normal cortisol and prolactin.
Key studies supporting the therapeutic use of this peptide.
Dose-dependent GH release comparable to GHRP-6 but without changes in ACTH, cortisol, prolactin, or FSH/LH.
Raun K, Hansen BS, Johansen NL, et al. — Eur J Endocrinol, 139(5):552-561 (1998) · PubMed
Dose-dependent GH peaks at 30-40 minutes, half-life ~2 hours, predictable PK/PD.
Gobburu JV, Agerso H, Jusko WJ, et al. — Pharm Res, 16(9):1412-1416 (1999) · PubMed
12 weeks significantly increased bone mineral content and density.
Svensson J, Lall S, Dickson SL, et al. — J Endocrinol, 165(3):569-577 (2000) · PubMed
Safe and well-tolerated; trends toward faster GI recovery.
Beck DE, Sweeney WB, McCarter MD, et al. — Int J Colorectal Dis, 29(12):1527-1534 (2014) · PubMed
Typical protocols used in clinical practice. Always consult a licensed provider for personalized dosing.
Subcutaneous (solo)
Subcutaneous (with CJC-1295 no DAC)
Subcutaneous (solo): Best at bedtime on empty stomach
Subcutaneous (with CJC-1295 no DAC): Synergistic GH release
Administer on empty stomach (1-2 hours fasted); food blunts GH response.
Bedtime dosing preferred to augment natural nocturnal GH surge.
Cycling (8-12 weeks on, 4 weeks off) prevents GHS receptor desensitization.
Excellent safety profile. Its selectivity means no cortisol, prolactin, or aldosterone elevation. Phase 2 trial confirmed safety in postoperative patients.
Stimulates endogenous GH rather than replacing it, preserving natural feedback. However, chronic use can still elevate IGF-1. Periodic monitoring recommended.
Not FDA-approved. Should not be used by individuals with active malignancies.
See how Ipamorelin compares to peptides with overlapping benefits.
| Peptide | Primary Use | Administration | Cycle Length | Key Differentiator |
|---|---|---|---|---|
| Ipamorelin | Anti-Aging & Body Composition | Injection (1-3x daily) | 8–12 weeks | Most selective GH secretagogue — clean pulsatile GH release without cortisol, prolactin, or appetite effects |
| SS-31 (Elamipretide) | Mitochondrial Restoration & Anti-Aging | Injection (daily) | Continuous (weeks to months) | Only peptide that directly targets cardiolipin on the inner mitochondrial membrane to restore electron transport chain efficiency |
| Semaglutide | Weight Loss | Injection (weekly), Oral (daily) | Ongoing | Most clinically validated weight-loss peptide with cardiovascular outcomes data from the SELECT trial |
| Tirzepatide | Weight Loss | Injection (weekly) | Ongoing | Only dual GIP/GLP-1 agonist, producing up to 22.5% weight loss — the highest of any pharmacotherapy |
| Tesamorelin | Body Composition & GHRH | Subcutaneous Injection | Ongoing daily | The only FDA-approved GHRH analog with Phase III data in over 800 patients, proven hepatoprotective effects, and physiologic pulsatile GH release |
Current FDA classification and compounding eligibility.
The FDA placed this substance in Category 2 of the 503A bulk drug substances evaluation, flagging significant safety risks. 503A compounding carries FDA enforcement risk, so most pharmacies decline to prepare it and many physicians hesitate to prescribe it.
Nomination withdrawn September 2024, then reviewed by PCAC on October 29, 2024. FDA cited unnatural amino acids, aggregation risks, and a literature report of death during IV administration for gastric motility. Remains ineligible for 503A compounding pending FDA final determination. Not among the 12 peptides HHS withdrew from Category 2 in April 2026.
PCAC reviewed ipamorelin for potential 503A inclusion
Removed from Category 2 (nomination withdrawn by nominators)
Placed in 503A Category 2 with significant safety risks identified
Last verified April 12, 2026. PepHookup tracks public FDA actions. This is not legal or medical advice.
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