Ipamorelin Overview
Mechanism of Action
Ipamorelin is a pentapeptide selective growth hormone secretagogue that mimics ghrelin at the GHS-R1a receptor on pituitary somatotrophs. Unlike other GH secretagogues (GHRP-6, hexarelin), Ipamorelin does not significantly affect cortisol, prolactin, or appetite — making it one of the cleanest GH-stimulating peptides available. It triggers GH release in a dose-dependent, pulse-like fashion.
~2 hours
Timing
Before bed (amplifies natural GH pulse). If split dosing, also upon waking.
Injection Site
Subcutaneous, lower abdomen
Food
Fast 2+ hours before. GH release blunted by glucose/insulin.
Common Stacks
- CJC-1295 no DAC — The gold standard GHRH+GHRP stack
- Tesamorelin — Alternative GHRH pairing
Ipamorelin Dosing Protocol
Standard Protocol
8–12 weeks100–300 mcg nightly
Best combined with CJC-1295 (no DAC) for synergistic effect.
Split Dosing
8–12 weeks100–200 mcg 2–3x/day
Multiple smaller pulses throughout the day. Often morning + night.
Ipamorelin Expected Timeline
Week 1–2
Improved sleep onset and depth
Week 3–4
Enhanced recovery; reduced post-exercise soreness
Week 6–8
Visible fat loss; improved skin elasticity
Week 8–12
Body composition improvement; sustained energy
Ipamorelin Side Effects
Mild hunger increase (less than GHRP-6)
Head rush post-injection (transient)
Water retention (mild)
Ipamorelin Research Studies
Ipamorelin, the first selective growth hormone secretagogue
Raun K, Hansen BS, Johansen NL, et al. — Eur J Endocrinol (1998)
Landmark study establishing ipamorelin as the first truly selective GH secretagogue, demonstrating potent GH release without affecting ACTH, cortisol, prolactin, or FSH/LH levels.
PubMed: 9916862Growth hormone secretagogues: history, mechanism of action, and clinical development
Ghigo E, Arvat E, Camanni F — Ann Endocrinol (2002)
Review of GHS mechanisms confirming ipamorelin’s selectivity profile and clinical applicability for age-related GH decline.
PubMed: 12191096Ipamorelin FAQ
How is Ipamorelin different from GHRP-6?
Both stimulate GH release via the ghrelin receptor, but GHRP-6 also significantly increases cortisol, prolactin, and appetite. Ipamorelin is selective — it releases GH without those unwanted side effects, making it the preferred choice.
Can I take Ipamorelin during the day?
Yes. Split dosing (morning + bedtime) creates multiple GH pulses. Just ensure you’re fasted for at least 2 hours before each dose, as insulin and blood sugar suppress GH release.