Ipamorelin Evidence Guide
Ipamorelin stands out among growth hormone secretagogues for one critical reason: it is the only GHRP that does not significantly elevate cortisol, ACTH, or prolactin at research doses. This selectivity makes it the cleanest tool for studying GH pulsatility in isolation. It has Phase 2 human data (post-operative ileus trial) confirming pharmacological activity. The body composition effects are real but modest - ipamorelin is not a substitute for exogenous GH, it is a physiologically cleaner way to study GH secretion.
Our Take
Ipamorelin stands out among growth hormone secretagogues for one critical reason: it is the only GHRP that does not significantly elevate cortisol, ACTH, or prolactin at research doses. This selectivity makes it the cleanest tool for studying GH pulsatility in isolation. It has Phase 2 human data (post-operative ileus trial) confirming pharmacological activity. The body composition effects are real but modest - ipamorelin is not a substitute for exogenous GH, it is a physiologically cleaner way to study GH secretion.
- Best for
- GH secretagogue research, clean GH pulsatility, stacking with GHRH analogs
- Evidence grade
- Level B
- Confidence
- Moderate
- Starting point
- 200mcg subcutaneous, before bed on an empty stomach
Benefits and Evidence
- Growth Hormone Release: Level B, includes human evidence - Reliably stimulates GH release in human studies. Dose-dependent increase in GH levels with preserved pulsatile release pattern.
- Body Composition: Level C, includes human evidence - Limited clinical data suggests improvements in lean body mass and reduction in body fat. Effects are modest compared to exogenous GH.
- Bone Density: Level C, includes human evidence - Preliminary evidence of improved bone mineral density through GH-mediated mechanisms. Long-term data lacking.
- Sleep Quality: Level C, includes human evidence - Anecdotal and limited clinical reports suggest improved sleep quality, likely mediated through increased GH release during sleep cycles.
Side Effects and Warnings
- Headache (most common)
- Water retention
- Numbness or tingling in extremities
- Possible increased hunger
- Lightheadedness
- Not FDA-approved for any indication
- May affect glucose metabolism
- Caution in individuals with active cancer
Research Dosage References
- <strong>Subcutaneous injection</strong> - 100-300 mcg - 1-3 times daily - Best administered on an empty stomach, especially before bed for sleep-related GH benefits.
- <strong>Subcutaneous (with CJC-1295)</strong> - 100-200 mcg - Once or twice daily - Often combined with CJC-1295 DAC or no-DAC for synergistic GH release.
Mechanism of Action
Ipamorelin works through targeted GH stimulation: 1. Ghrelin receptor binding: Selectively binds to GHS-R1a receptors on pituitary somatotrophs. 2. GH pulse stimulation: Triggers pulsatile GH release similar to natural physiological patterns. 3. Selective action: Unlike other GHRPs, does not significantly increase cortisol, ACTH, or prolactin at therapeutic doses. 4. IGF-1 elevation: Indirect increase in IGF-1 through elevated GH levels. 5. Synergy with GHRH: Can be combined with GHRH analogs (like CJC-1295) for amplified GH release.
Legal Status
Ipamorelin is not FDA-approved and is classified as a research peptide. Banned by WADA in competitive sports. Available for research purposes in most jurisdictions. Not a controlled substance but cannot be marketed for human consumption.
Primary Sources
- Ipamorelin, a new growth-hormone-releasing peptide/secretagogue. Eur J Endocrinol, 1998.
- Safety and pharmacokinetics of ipamorelin in healthy volunteers. J Clin Pharmacol, 1999.
- Growth hormone secretagogues: clinical applications. J Endocrinol, 2005.