Ipamorelin
The cleanest GHRP — selective pituitary GH stimulation with zero cortisol or prolactin side effects.
Research facts
| Half-life | ~2h |
|---|---|
| Route | SubQ / IM |
| Typical dose | 200–300 mcg |
| Frequency | 2–3× daily (bedtime essential) |
| Solvent | Bacteriostatic water |
| pH | 5.0–7.0 |
| Stability | 30 days at +4°C |
Mechanism of action
Ipamorelin is a selective pentapeptide ghrelin receptor (GHS-R1a) agonist that triggers a clean, pulsatile growth hormone release from the anterior pituitary somatotroph cells. Unlike earlier GHRPs (GHRP-2, GHRP-6, Hexarelin), Ipamorelin produces negligible cortisol, prolactin, or ACTH stimulation — making it the most selective GHRP available.
It activates the hypothalamic-pituitary axis to produce GH pulses that closely mimic natural physiological patterns. The GH pulse peaks approximately 15–30 minutes post-injection, then returns to baseline, preserving normal feedback dynamics. When combined with a GHRH analogue (CJC-1295 no-DAC, Sermorelin), it produces a 4–6× amplification of GH output through complementary mechanisms: GHRH amplifies the amplitude (how much GH is released per pulse) while GHRP triggers the pulse (timing and initiation).
Ipamorelin was reapproved in the US in March 2026 after temporary Category 2 restriction.
Documented effects (research-model)
- Clean, pulsatile GH stimulation without cortisol or prolactin elevation
- Body composition improvement via GH/IGF-1 axis
- Deep sleep architecture enhancement (GH pulse aligns with slow-wave sleep)
- Recovery acceleration via IGF-1 elevation
- Bone density support in GH-deficient models
- Mild appetite regulation via ghrelin pathway
Research protocols
| Protocol | Dose | Frequency | Cycle | Vial |
|---|---|---|---|---|
| Standard | 200 mcg | 2× daily (AM fasted + bedtime) | 12 weeks on / 4 off | 2mg / 2mL BAC water |
| Advanced | 300 mcg with CJC-1295 | Same syringe, 2× daily | 12 weeks | 5mg / 2mL BAC water |
Research context only. Not medical advice. Consult a qualified healthcare professional before any protocol decision.
Synergies
- CJC-1295 HIGH
The GH Pulse Stack — CJC-1295 amplifies amplitude (GHRH); Ipamorelin triggers the pulse (GHRP). 4–6× GH output. Can be combined in same syringe. - Sermorelin HIGH
Same GHRH+GHRP synergy with the longest clinical safety record. - BPC-157 MODERATE
Local tissue repair + systemic GH pulse for amplified recovery protocol.
Myths & misconceptions
Evidence gaps
- No large-scale randomised human trials for body composition or athletic recovery.
- Long-term effects on the GH axis with sustained use (>12 months) are undocumented.
- Optimal dosing frequency in humans (2× vs. 3× daily) not established by RCT.
Safety notes
Well-characterised safety profile. No cortisol or prolactin elevation at standard doses. Monitor IGF-1 and fasting glucose. Reapproved US March 2026.
Biomarkers to monitor
Primary-source citations
- PMID 9849822 — Ipamorelin, the first selective growth hormone secretagogue (Eur J Endocrinol. 1999)
- PMID 18540025 — Growth hormone secretagogues: clinical development and therapeutic potential (Nat Rev Drug Discov. 2008)
Frequently asked
What is Ipamorelin?
Ipamorelin (Selective Growth Hormone Releasing Peptide (GHRP)) is a research compound classified in our library as Tier C — Limited human trials; effect size uncertain.. The cleanest GHRP — selective pituitary GH stimulation with zero cortisol or prolactin side effects.
What is the evidence tier for Ipamorelin?
We classify Ipamorelin as Tier C: Limited human trials; effect size uncertain. See our full peptide evidence tiers explainer for how we assign S/A/B/C/D.
What is the research dose of Ipamorelin?
For Ipamorelin, typical research dose is 200–300 mcg, route is SubQ / IM, half-life is ~2h. Protocols vary by research goal — see the protocols section on this page for standard and advanced dosing schedules. Research use only, not medical advice.
What does Ipamorelin stack well with?
Ipamorelin stacks well with CJC-1295. The GH Pulse Stack — CJC-1295 amplifies amplitude (GHRH); Ipamorelin triggers the pulse (GHRP). 4–6× GH output. Can be combined in same syringe.
Is Ipamorelin safe?
Well-characterised safety profile. No cortisol or prolactin elevation at standard doses. Research context only — no compound on this site is approved for human therapeutic use unless explicitly noted.