Description
Ipamorelin — Research & Data
A highly selective growth hormone secretagogue that stimulates GH release without significantly affecting cortisol, prolactin, or ACTH levels. Known for its favorable safety profile among GH peptides.
How Ipamorelin Works
Ipamorelin selectively binds GHS-R1a (ghrelin receptor) on pituitary somatotroph cells, triggering GH release without activating ACTH or cortisol pathways. This selectivity comes from its pentapeptide structure that mimics ghrelin’s GH-releasing action without its broader endocrine effects.
Mechanisms of Action
GHS-R Agonism
Selectively binds growth hormone secretagogue receptor (ghrelin receptor) on pituitary somatotrophs to trigger GH release.
Selective Stimulation
Does not significantly stimulate ACTH, cortisol, or prolactin, unlike other GHRPs, providing a cleaner GH response.
Synergy with GHRH
Works synergistically with GHRH analogs (e.g., CJC-1295) to amplify pulsatile growth hormone output.
What Research Has Shown
Animal studies demonstrate potent, dose-dependent GH release comparable to GHRP-6 but without cortisol or prolactin elevation. Bone density studies show increased bone mineral content and periosteal bone formation in ovariectomized rat models. Limited human data exists beyond Phase 1/2 trials for post-operative ileus.
Dosing Information from Research
Research protocols typically use 200–300 µg subcutaneously, 1–3 times daily. Optimal timing is 30 minutes before meals or at bedtime to align with natural GH secretion patterns. Often combined with CJC-1295 (no DAC) at a 1:1 ratio.
Pharmacokinetics
Ipamorelin has a half-life of approximately 2 hours. Peak GH release occurs 30–60 minutes post-injection. It does not accumulate significantly with repeated dosing. Metabolism is hepatic with renal excretion.
How It Works in the Body
After injection, ipamorelin binds GHS-R1a on pituitary somatotrophs, triggering intracellular calcium signaling that releases stored GH granules. The GH pulse then stimulates hepatic IGF-1 production. Unlike GHRP-6, ipamorelin does not activate the HPA axis (no ACTH/cortisol) or stimulate appetite significantly.
Important Notes
- Ipamorelin is the most selective GHRP — it does not raise cortisol, ACTH, or prolactin.
- It was studied in Phase 2/3 trials for post-operative ileus but did not achieve primary endpoints.
- Ipamorelin does not significantly stimulate appetite (unlike GHRP-6 which acts as a strong ghrelin mimetic).
Safety Profile from Research
What clinical studies report
Ipamorelin has been well-tolerated in human clinical trials (Phase 2/3 for post-operative ileus). The most common side event was mild, transient headache. No significant cardiovascular or endocrine adverse effects were reported.
Treatment Discontinuation Rates
Less than 5% in Phase 2 trials, primarily due to headache or injection site discomfort.
Study Exclusion Criteria
Patients with pituitary disorders, active malignancy, or uncontrolled diabetes were excluded from clinical trials.
Researcher Notes
- Ipamorelin’s selectivity makes it ideal for GH research without confounding cortisol/prolactin variables.
- It is the preferred GHRP for combination protocols with GHRH analogs (CJC-1295).
- Bedtime dosing may enhance the natural nocturnal GH surge.
- Desensitization is less likely than with GHRP-6 due to lower receptor internalization.
Compound Information
Storage Requirements
Lyophilized
Store at -20°C for long-term. Stable at 2-8°C for up to 6 months.
Reconstituted
Use within 28 days when stored at 2-8°C.
Light Sensitivity
Low light sensitivity. Standard storage is sufficient.
Research Status — Where It Stands
Ipamorelin completed Phase 2/3 trials for post-operative ileus (did not meet primary endpoints). Extensively used in preclinical GH research. Not FDA-approved for any indication. Active research compound.
Reviews
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