Ipamorelin
Growth Hormone Secretagogue · Selective GHRP
Selective GHRP that stimulates natural GH production from the pituitary with minimal cortisol and prolactin disruption. Known for its excellent safety profile and ability to produce consistent GH pulses without significant side effects common to other growth hormone releasing peptides.
Overview
Selective GHRP that stimulates natural GH production from the pituitary with minimal cortisol and prolactin disruption. Known for its excellent safety profile and ability to produce consistent GH pulses without significant side effects common to other growth hormone releasing peptides.
Binds selectively to ghrelin receptors in pituitary gland, stimulating natural GH release with direct systemic delivery via injection, consistent GH pulse stimulation, no significant cortisol or prolactin elevation, and minimal hunger response.
Research indications
What the compound has been studied for, grouped by body system. Effect size is the reported magnitude where it was measured — not a recommendation.
Consistent GH elevation 30-60 minutes post-injection, maintaining natural pulsatile patterns.
Increases insulin-like growth factor-1 through natural GH pathways.
Supports cellular regeneration, collagen synthesis, and tissue repair.
Promotes muscle growth and maintenance through GH-mediated pathways.
Enhances lipolysis and metabolic rate through natural GH elevation.
Improved sleep latency and increased slow-wave sleep duration.
Enhanced recovery markers and reduced soreness after training.
A large effect in a weak study and a small effect in a strong one are different things. Effect size is never evidence of use in people.
- Class
- Growth hormone secretagogue
- Chain length
- 5 residues
- Molecular weight
- 711.85 Da
- Half-life
- ~2 h
- Typical dose
- 200-300 mcg per injection
- Frequency
- 1-3 times daily depending on goals (1x for longevity, 2-3x for performance)
- Cycle length
- 3-6 months
- Storage
- Lyophilized: Room temperature. Reconstituted: 2-8°C, use within 28 days
Molecular data
- Type
- Growth hormone secretagogue
- Molecular weight
- 711.85 Da
- Chain length
- 5 residues
- Half-life
- 120 min
Dosing reference
Doses reported in the literature and by suppliers. These are a record of what has been used in research — reference, never instruction.
| Context | Route | Amount | Frequency |
|---|---|---|---|
| General Health & Longevity | SubQ | 200mcg | 1x daily before bed |
| Body Composition | SubQ | 250-300mcg | 2x daily (morning, pre-workout) |
| Athletic Performance | SubQ | 200-250mcg | 2-3x daily |
| Sleep & Recovery | SubQ | 200mcg | 1x daily 30min before bed |
| Anti-Aging Protocol | SubQ | 200-250mcg | 1-2x daily |
Interactions
Extends GH release for optimal hormone cycles. Popular combination.
Enhances GH receptor upregulation and effectiveness.
Complementary for recovery and tissue repair.
Both stimulate GH; choose one to avoid receptor oversaturation.
Redundant GH pathways may cause receptor desensitization.
Similar mechanism with higher hunger effects; redundant.
Quality checklist
- ✓White, fine crystalline powder with no clumping
- ✓Clear solution after BAC water reconstitution
- ✓Mild hunger response 20-30 minutes post-injection
- ✓Slight drowsiness at bedtime doses
- !Minimal or no physiological response after 2 weeks (check source)
- ×Yellow or discolored powder (suggests degradation)
- ×Cloudy solution after reconstitution
- ×No response after extended use
What to expect
Safety
- Mild hunger increase 20-30 minutes post-injection
- Slight drowsiness when taken before bed
- Water retention (mild)
- Signs of receptor desensitization (reduced response after 3-4 months)
- Unusual joint pain or swelling
- Persistent numbness or tingling
- Pregnancy or breastfeeding
- Active cancer or history of cancer
- Severe kidney or liver disease
FAQ
Why do users prefer ipamorelin over other GHRPs?
Ipamorelin is the most selective GHRP—it stimulates GH release without the appetite stimulation of GHRP-6, the prolactin elevation of GHRP-2, or the cortisol/ACTH effects of hexarelin. This selectivity makes it ideal for those wanting clean GH elevation with minimal side effects.
Is ipamorelin good for bedtime dosing?
Yes, excellent. A 200mcg dose 30 minutes before bed improves sleep quality and supports the natural nocturnal GH pulse. Many users report deeper, more restorative sleep with minimal side effects compared to morning dosing.
Can I stack ipamorelin with CJC-1295?
Yes, this is a popular and synergistic combination. CJC-1295 provides baseline GH elevation while ipamorelin adds pulsatile spikes. Together they extend GH release duration and amplitude beyond either peptide alone.
How long before ipamorelin stops working?
Ipamorelin typically maintains efficacy for 3-4 months before receptor desensitization develops. Many users take 4-week breaks every 12 weeks to reset receptor sensitivity and maintain responsiveness over time.
References
- 1Ipamorelin, the first selective growth hormone secretagogueRaun K, Hansen BS, Johansen NL, et al. · European Journal of Endocrinology · 1998
Ipamorelin is the first GHRP-receptor agonist with selectivity for GH release similar to GHRH; does not release ACTH or cortisol even at doses over 200-fold the ED50 for GH.
reviewPubMed 9849822 ↗ - 2Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteersZdravkovic, M., et al. · British Journal of Clinical Pharmacology · 1999
Dose-escalation study in 40 healthy males established terminal half-life of 2 hours, clearance of 0.078 L/h/kg. Ipamorelin induced single-episode GH release peaking at 0.67 hours with dose-proportional pharmacokinetics.
reviewPubMed 10496658 ↗ - 3Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in ratsJohansen, P.B., et al. · Growth Hormone & IGF Research · 1999
Ipamorelin dose-dependently increased longitudinal bone growth rate from 42 to 52 mcm/day and produced pronounced dose-dependent body weight gain in adult female rats over 15 days.
animalPubMed 10373343 ↗ - 4The growth hormone secretagogue ipamorelin counteracts glucocorticoid-induced decrease in bone formation of adult ratsSvensson, J., et al. · Calcified Tissue International · 2001
In 8-month-old female rats treated for 3 months, ipamorelin combined with glucocorticoid increased maximum tetanic tension and periosteal bone formation rate 4-fold compared to glucocorticoid alone.
animalPubMed 11735244 ↗ - 5Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patientsGreenwood-Van Meerveld, B., et al. · International Journal of Colorectal Disease · 2014
Multicenter, double-blind, placebo-controlled trial in 117 bowel resection patients. Ipamorelin 0.03 mg/kg IV twice daily for up to 7 days was well tolerated but did not significantly improve postoperative ileus outcomes versus placebo.
human-rctPubMed 25331030 ↗