Hexarelin vs Melanotan II
A neutral, side-by-side comparison of two performance & growth hormone peptides — their mechanisms, dosing ranges, administration routes, side effects, and research evidence. For research and educational purposes only.
Hexarelin
Hexarelin is a potent synthetic hexapeptide GHRP (Growth Hormone-Releasing Peptide) that stimulates GH release via the ghrelin receptor. It produces among the highest GH pulses of any GHRP, but also elevates cortisol and prolactin — a trade-off that distinguishes it from more selective options like Ipamorelin.
Full profileMelanotan II
Melanotan II (MT-II) is a cyclic lactam analog of alpha-melanocyte stimulating hormone (α-MSH) that acts as a potent, non-selective melanocortin receptor agonist (MC1R, MC3R, MC4R, MC5R). Developed at the University of Arizona in the late 1980s, it produces eumelanin-driven skin darkening (tanning) via MC1R, sexual arousal and spontaneous erections via MC4R, and appetite suppression via MC3R/MC4R. Bremelanotide (PT-141) — now FDA-approved for female sexual dysfunction — was derived from Melanotan II.
Full profile| Hexarelin | Melanotan II | |
|---|---|---|
| Category | Performance & Growth Hormone | Performance & Growth Hormone |
| Also known as | Examorelin, EP 23905, MF-6003 | MT-II, MTII, Cyclo[Nle4,D-Phe7]-α-MSH |
| Evidence | Preclinical only | Research-stage |
| Dosing range | 50mcg–200mcg mcg, 1–3x daily (cycling recommended to prevent desensitization) | 250mcg–1000mcg mcg, Daily during loading phase; 2–3x weekly for maintenance |
| Administration | Subcutaneous injection, Intramuscular injection | Subcutaneous injection (most common), Intranasal (less effective, lower bioavailability) |
| Key side effects | Cortisol elevation, Prolactin elevation, Water retention, Increased appetite | Nausea (most common — especially first 30–60 minutes post-injection), Facial flushing, Spontaneous erections (males — often unwanted at higher doses), Fatigue / yawning post-injection |
| Cited sources | 1 reference | 3 references |
Key differences
- Evidence level differs: Hexarelin is preclinical only, while Melanotan II is research-stage.
- Administration: Hexarelin — Subcutaneous injection, Intramuscular injection; Melanotan II — Subcutaneous injection (most common), Intranasal (less effective, lower bioavailability).
- Frequency: Hexarelin is typically 1–3x daily (cycling recommended to prevent desensitization); Melanotan II is Daily during loading phase; 2–3x weekly for maintenance.
- Research depth: this profile cites 1 source for Hexarelin vs 3 for Melanotan II.
How each works
Hexarelin
Hexarelin produces dose-dependent GH release significantly greater than GHRP-6 or Ipamorelin. It also has direct cardioprotective effects via CD36 receptor binding, independent of GH — making it unique among GHRPs. Studies show protection from ischemic cardiac injury and myocardial fibrosis reduction in animal models. Desensitization occurs with chronic continuous use.
Melanotan II
Melanotan II's broad melanocortin receptor agonism produces a constellation of effects across multiple systems. MC1R activation in melanocytes upregulates tyrosinase, the rate-limiting enzyme in melanin synthesis, producing UV-independent skin darkening. MC4R activation in the CNS and spinal cord drives sexual arousal and erectogenic effects more potent than most PDE5 inhibitors, and also produces appetite suppression and reduced food intake (the same pathway exploited by weight-loss drugs targeting the melanocortin system). MC3R activation contributes to energy homeostasis effects.
This comparison aggregates public research and structured profile data for informational purposes only. It is not medical advice and does not recommend either compound for human use. Consult a qualified healthcare provider before considering any peptide.