Ipamorelin
Growth Hormone Secretagogue · Selective GHRP
Selective GHRP that raises natural GH production from the pituitary while disruption of cortisol and prolactin stays minimal. It is known for a clean safety profile and for consistent GH pulses, free of the significant side effects common to other growth hormone releasing peptides.
Overview
Selective GHRP that raises natural GH production from the pituitary while disruption of cortisol and prolactin stays minimal. It is known for a clean safety profile and for consistent GH pulses, free of the significant side effects common to other growth hormone releasing peptides.
Selective binding at pituitary ghrelin receptors drives natural GH release, and injection puts the peptide into systemic circulation directly. GH pulses are stimulated consistently, cortisol and prolactin are not raised to any significant degree, and the hunger response is minimal.
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.
GH holds elevated consistently 30–60 minutes after injection, the natural pulsatile pattern preserved.
Insulin-like growth factor-1 rises by way of the natural GH pathways.
Tissue repair, collagen synthesis and regeneration at the cellular level are all supported.
GH-mediated pathways drive muscle growth and its maintenance.
Lipolysis and metabolic rate both climb under natural GH elevation.
Sleep latency improved, and the duration of slow-wave sleep increased.
After training, recovery markers were enhanced and soreness reduced.
- Class
- Growth hormone secretagogue
- Research status
- Well studied
- Chain length
- 5 residues
- Molecular weight
- 711.85 Da
- Half-life
- ~2 h
- Typical dose
- 200–300 µg per injection
- Frequency
- 1–3 times daily (reported range)
- 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
Levels in single-dose multiples. A shape, not a pharmacokinetic prediction.
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
A popular combination; GH release runs longer, giving optimal hormone cycles.
Raises GH receptor upregulation, and effectiveness with it.
Complementary in recovery and in tissue repair.
GH is stimulated by both; using one alone avoids receptor oversaturation.
GH pathways are redundant here, and receptor desensitization may follow.
The mechanism is similar and hunger effects higher; redundant.
What to expect
Safety
Mechanistic flags — properties of the pathway, not observed adverse events.
- Water retention (mild)
- Hunger up mildly, 20–30 minutes after injection
- Slight drowsiness from a dose taken before bed
- Persistent numbness or tingling
- Joint pain or swelling that is unusual
- Receptor desensitization signs — response reduced after 3–4 months
- Pregnancy or breastfeeding
- Severe disease of the kidney or liver
- Cancer now active, or cancer in the past
Quality checklist
What to confirm before trusting a batch of research material. A verification aid — not an endorsement of any supplier.
- Third-party Certificate of AnalysisIndependent lab · dated · lot-matched.
- HPLC purity ≥ 98%Reverse-phase trace included.
- Mass-spec confirms 711.85 g/molMALDI-TOF or ESI-MS.
- Counterion stated (acetate ≫ TFA)TFA salts can confound bioassays.
- Endotoxin / sterility statementRelevant once reconstituted.
- Lyophilised · cold-chain shippedStored −20 °C, shipped on ice.
- Labelled “research use only”No therapeutic or dosing claims.
Recorded signals for this compound · 8
- ✓Fine crystalline powder, white, free of clumping
- ✓Solution clear once reconstituted with BAC water
- ✓Hunger response, mild, 20–30 minutes after injection
- ✓Doses at bedtime bringing slight drowsiness
- !After 2 weeks, physiological response minimal or absent (check the source)
- ×Powder yellow or otherwise discolored, which suggests degradation
- ×Extended use producing no response
- ×Solution cloudy once reconstituted
FAQ
How does ipamorelin's selectivity compare with other GHRPs?
Among GHRPs ipamorelin is the most selective: GH release is stimulated without GHRP-6's appetite stimulation, without GHRP-2's prolactin elevation, and without the cortisol/ACTH effects of hexarelin. That selectivity is what makes it ideal where the goal is clean GH elevation with minimal side effects.
Is ipamorelin well suited to bedtime dosing?
Yes, and excellently so. A dose of 200 µg, 30 minutes before bed, improves the quality of sleep and supports the nocturnal GH pulse that occurs naturally. Reports describe sleep that is deeper and more restorative, side effects minimal relative to morning dosing.
Is ipamorelin stacked with CJC-1295?
Yes; the pairing is popular and synergistic. Baseline GH elevation comes from CJC-1295, while the pulsatile spikes come from ipamorelin. Duration and amplitude of GH release both extend past what either peptide reaches alone.
How long does ipamorelin keep working before desensitization?
Efficacy typically holds for 3–4 months, at which point receptor desensitization develops. A common pattern is a 4-week break every 12 weeks, which resets receptor sensitivity and keeps responsiveness up 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.
Animal in vivoPubMed 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.
Human RCTPubMed 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.
Animal in vivoPubMed 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.
Animal in vivoPubMed 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 ↗
In ferrets, anamorelin and ipamorelin each blunted the weight loss caused by cisplatin by roughly 24%, and anamorelin additionally acted as an anti-emetic through a central mechanism, broadening the clinical scope for ghrelin mimetics.