Melanotan II
Also known as: MT-II, MT2
Molecular Identifiers
Overview
Melanocortin receptor agonist that promotes tanning. Synthetic α-MSH analog. Stimulates melanin production in melanocytes.
The main appeal of Melanotan II is accelerated tanning through MC1R receptor stimulation, with a more potent effect than Melanotan I. Because it also acts on MC3R and MC4R, it produces systemic side effects: increased libido, spontaneous erection, decreased appetite, and facial flushing — frequently reported in the first days of use.
It has no regulatory approval from any agency (FDA, EMA, ANVISA). It is widely sold on the research market and used off-label for cosmetic tanning via subcutaneous injection, without formal medical supervision. Health agencies warn about the darkening of nevi and the need for dermatological follow-up. Starting with a low dose to assess tolerance is common practice.
Within the melanocortin family, Melanotan II is the pan-agonist of the pathway (MC1R, MC3R, MC4R, MC5R): it produces pigmentation like Melanotan I (MC1R-selective) but with the sexual and central effects that are absent from it, precisely because it engages MC3R-MC4R. The observation of that pro-sexual effect is what gave rise to PT-141 (bremelanotide), an analog focused on MC4R without a pigmentation goal, and it contrasts with setmelanotide (MC4R-selective for monogenic obesity) and with endogenous α-MSH (very short half-life).
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂ Cyclic peptide with non-natural amino acids (Nle, D-Phe)
Half-life
~30-60 minutes
Administration Route
Subcutaneous
Category
Cosmetic & Skin
Mechanism of Action
- MC1R receptor agonism (pigmentation)
- Stimulation of melanin production
- Activity at MC3R and MC4R receptors (appetite, libido)
- Photoprotection through increased melanin
Dosage Protocol
Data compiled from the literature. This does not constitute medical advice.
| Parameter | Value |
|---|---|
| Dose | 250-500 mcg per injection |
| Frequency | 3-7 times per week |
| Timing | Any time of day |
| Duration | Until desired pigmentation |
Reported Side Effects
Adverse effects described in the literature. Severity and frequency vary between individuals.
- Nausea
- Facial flushing
- Darkening of nevi
- Increased libido
- Spontaneous erection
Product Properties
| Purity | >99% |
| Appearance | White lyophilized powder |
| Solubility | Soluble in water and bacteriostatic water |
| Source | Solid-phase peptide synthesis (SPPS) |
| Storage | Lyophilized: -20°C for up to 2 years, 2-8°C for up to 6 months. Reconstituted: 2-8°C for up to 4 weeks. Cyclic structure with lactam bridge provides enhanced stability. Protect from light and moisture. Avoid repeated freeze-thaw cycles. |
Presentations & Preparation
Vials of Melanotan II found in the research market:
Reconstitution
- Diluent: Bacteriostatic water
- Volume: 2 ml per vial
- Inject the diluent slowly against the vial wall
- Gently swirl until fully dissolved
- Never shake
Storage
- Lyophilized: Refrigerated 2-8°C
- Reconstituted: Refrigerated 2-8°C (up to 30 days)
- Protect from direct light
- Do not freeze after reconstitution
Scientific Studies
Published studies on Melanotan II.
Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II
Wessells H, Levine N, Hadley ME, Dorr R, Hruby V
Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study
Dorr RT, Lines R, Levine N, Brooks C, Xiang L, Hruby VJ, Hadley ME
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