Melanotan II vs Tesamorelin
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 profileTesamorelin
Tesamorelin is an FDA-approved synthetic analog of growth hormone-releasing hormone (GHRH). Approved in 2010 as Egrifta, it is the only GHRH peptide with an approved clinical indication — reduction of excess visceral abdominal fat in people with HIV-associated lipodystrophy. It has the most robust human trial evidence of any growth hormone secretagogue, including dedicated studies on visceral fat and liver fat.
Full profile| Melanotan II | Tesamorelin | |
|---|---|---|
| Category | Performance & Growth Hormone | Performance & Growth Hormone |
| Also known as | MT-II, MTII, Cyclo[Nle4,D-Phe7]-α-MSH | Egrifta, Egrifta SV, TH9507, GHRH analog |
| Evidence | Research-stage | FDA-approved |
| Dosing range | 250mcg–1000mcg mcg, Daily during loading phase; 2–3x weekly for maintenance | 1.28mg–2mg mg, once daily (subcutaneous) |
| Administration | Subcutaneous injection (most common), Intranasal (less effective, lower bioavailability) | Subcutaneous injection (abdomen, with site rotation) |
| 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 reactions (erythema, pruritus), Peripheral edema, Arthralgia (joint pain), Myalgia |
| Cited sources | 3 references | 5 references |
Key differences
- Evidence level differs: Melanotan II is research-stage, while Tesamorelin is fda-approved.
- Administration: Melanotan II — Subcutaneous injection (most common), Intranasal (less effective, lower bioavailability); Tesamorelin — Subcutaneous injection (abdomen, with site rotation).
- Dosing units differ: Melanotan II is dosed in mcg, Tesamorelin in mg — they operate at different scales.
- Frequency: Melanotan II is typically Daily during loading phase; 2–3x weekly for maintenance; Tesamorelin is once daily (subcutaneous).
- Research depth: this profile cites 3 sources for Melanotan II vs 5 for Tesamorelin.
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.
Tesamorelin
Tesamorelin stimulates pulsatile growth hormone (GH) release from the pituitary, raising serum IGF-1 and preferentially reducing visceral adipose tissue (VAT). FDA-registration trials (Falutz et al., NEJM 2007; JAIDS 2010) showed ~15% VAT reduction versus placebo over 26 weeks. Later randomized trials (Stanley et al., JAMA 2014; Lancet HIV 2019) extended the evidence to liver fat, showing meaningful reductions in hepatic fat fraction and attenuated fibrosis progression in HIV-associated NAFLD.
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.