Melanotan II vs Sermorelin
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.
Melanotan 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 profileSermorelin
Sermorelin is a synthetic analog of the first 29 amino acids of GHRH (Growth Hormone-Releasing Hormone). It was FDA-approved for pediatric GH deficiency diagnosis and is widely used off-label in anti-aging and performance medicine. It stimulates pulsatile GH release more physiologically than exogenous GH.
Full profile| Melanotan II | Sermorelin | |
|---|---|---|
| Category | Performance & Growth Hormone | Performance & Growth Hormone |
| Also known as | MT-II, MTII, Cyclo[Nle4,D-Phe7]-α-MSH | GHRH 1-29, GRF 1-29 NH2, Geref |
| Evidence | Research-stage | FDA-approved |
| Dosing range | 250mcg–1000mcg mcg, Daily during loading phase; 2–3x weekly for maintenance | 100mcg–500mcg mcg, once daily (before sleep) |
| Administration | Subcutaneous injection (most common), Intranasal (less effective, lower bioavailability) | Subcutaneous injection |
| Key side effects | Nausea (most common — especially first 30–60 minutes post-injection), Facial flushing, Spontaneous erections (males — often unwanted at higher doses), Fatigue / yawning post-injection | Injection site redness, Headache, Flushing, Dizziness |
| Cited sources | 3 references | 1 reference |
Key differences
- Evidence level differs: Melanotan II is research-stage, while Sermorelin is fda-approved.
- Administration: Melanotan II — Subcutaneous injection (most common), Intranasal (less effective, lower bioavailability); Sermorelin — Subcutaneous injection.
- Frequency: Melanotan II is typically Daily during loading phase; 2–3x weekly for maintenance; Sermorelin is once daily (before sleep).
- Research depth: this profile cites 3 sources for Melanotan II vs 1 for Sermorelin.
How each works
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.
Sermorelin
Sermorelin works by binding pituitary GHRH receptors to stimulate GH secretion within the body's natural feedback loop. Unlike synthetic GH, it does not suppress endogenous production. Clinical studies show improved body composition, sleep quality, and IGF-1 levels in GH-deficient adults. Its short half-life (~10 min) means it requires daily dosing.
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.