Ipamorelin
GHS-R1a Agonist (selective)
Ipamorelin is a selective growth hormone secretagogue that triggers pulsatile GH release without significant cortisol or prolactin elevation. Not FDA-approved; WADA-prohibited.
Overview
Ipamorelin is a synthetic pentapeptide that acts as a selective growth hormone secretagogue (GHS). It works by binding to the ghrelin receptor (also known as GHS-R1a) on pituitary cells, triggering a short, pulsatile release of growth hormone (GH). Ipamorelin is noted for its selectivity — unlike some other growth hormone releasing peptides, it does not significantly stimulate the release of cortisol, prolactin, or aldosterone, which are considered undesirable side effects in the context of GH modulation.
Ipamorelin has been studied in early-phase clinical research and pharmacokinetic modeling, but it has not advanced through full clinical development and is not FDA-approved for any human use. It remains one of the most discussed research peptides in the growth hormone secretagogue category.
Research context
Published clinical pharmacology data on ipamorelin include Phase 1 and pharmacokinetic/pharmacodynamic (PK/PD) studies in healthy adults. A 1999 PK/PD modeling study characterized ipamorelin's GH response as a short, dose-dependent pulse with a terminal half-life of approximately two hours after intravenous administration. Additional research explored its effects on postoperative bowel function, where it showed some promise as a prokinetic agent but did not advance to approval.
Ipamorelin is frequently discussed in combination with CJC-1295, based on the rationale that combining a GHRH analog with a ghrelin receptor agonist could produce complementary effects on GH release. However, well-controlled human trials evaluating this combination for body composition or performance outcomes have not been published.
Safety and regulatory framing
FDA compounding safety concern; WADA prohibited; not approved for human use
Ipamorelin is not FDA-approved for any human use. The FDA has flagged it as a substance with safety concerns in the compounding context, and it is prohibited by WADA as a growth hormone secretagogue. Reported serious adverse events exist in some clinical contexts.
Products available from research chemical suppliers are unregulated and not manufactured to pharmaceutical standards. Readers should consult a licensed healthcare provider before considering any unapproved substance. Regulations vary by jurisdiction.
References
- Raun K, et al. "Ipamorelin, the First Selective Growth Hormone Secretagogue." Eur J Endocrinol (1998) ↗European Journal of Endocrinology
- Gobburu JVS, et al. "Pharmacokinetic-Pharmacodynamic Modeling of Ipamorelin." J Clin Pharmacol (1999) ↗Journal of Clinical Pharmacology
- FDA Bulk Drug Substance Compounding Safety Concerns ↗FDA.gov
- WADA Prohibited List — Growth Hormone Secretagogues ↗WADA
Research information only
Peptide Daily is an informational resource only. Peptide research chemicals are not approved for human use by the FDA unless otherwise noted. Nothing on this site constitutes medical advice. Consult a qualified healthcare provider before using any peptide or research chemical.
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