Melanotan II
Also known as: MT-II, Melanotan-2
Overview
Melanotan II is a synthetic cyclic heptapeptide analog of alpha-melanocyte stimulating hormone (α-MSH). Originally developed at the University of Arizona as a sunless tanning agent, it non-selectively activates melanocortin receptors MC1R through MC5R. While it produces strong skin pigmentation, its activation of MC3R and MC4R also drives spontaneous erectile responses and sexual stimulation, effects that led to development of the more targeted PT-141. Melanotan II is not FDA-approved and carries significant safety concerns.
Mechanism of Action
Melanotan II binds to and activates multiple melanocortin receptors. MC1R activation drives melanogenesis by stimulating tyrosinase and melanogenic enzymes, producing eumelanin (brown/black pigment). MC3R and MC4R activation in the hypothalamus drives sexual arousal, erection, and appetite suppression. MC5R activation affects exocrine glands. The broad receptor binding profile explains both the therapeutic effects and the adverse effect profile.
Potential Benefits
- Potent melanogenesis and sunless tanning effect
- Sexual arousal and libido enhancement
- Appetite suppression and potential weight loss
- Strong erection-promoting effects
- Tanning reduces UV radiation damage risk (theoretical protective benefit)
Dosage Protocols
The following reflects doses used in published research studies. This is not medical advice. Consult a qualified healthcare professional.
| Typical Range | 0.25-1 mg/dose |
| Beginner | 0.25 mg initial dose; then 0.5 mg every other day |
| Intermediate | 0.5-0.75 mg every 1-3 days for maintenance |
| Advanced | 1 mg every 1-3 days |
| Cycle Duration | 4-6 weeks loading, then maintenance as desired |
| Cycle Off | Variable; tanning effects persist for weeks after cessation due to melanin accumulation |
Start with 0.25 mg test dose to gauge nausea response. Nausea is dose-dependent and subsides after initial doses. Takes 2-4 weeks for tanning effects. Requires UV exposure for maximal melanin stimulation. Aphrodisiac effects occur at lower doses and earlier than tanning.
Use our Reconstitution Calculator to determine exact syringe units for your protocol.
Routes of Administration
Subcutaneous Injection High — systemic melanocortin receptor activation
Standard method. Start with 0.25 mg to assess tolerance, then 0.5–1 mg daily until desired pigmentation. Maintenance 1–2x per week.
Read our full Routes of Administration Guide for detailed comparison of all delivery methods.
Stacking Protocols
Popular research stacks involving Melanotan II:
Tanning & Libido Stack
Melanotan II for melanocortin-mediated tanning with PT-141 for targeted sexual function enhancement. MT-II provides both effects but PT-141 adds more specific MC4R activation for libido.
Fat Loss & Tanning Stack
Body recomposition with aesthetic benefits. Melanotan II for appetite suppression and tanning, AOD-9604 for fat metabolism, MOTS-C for metabolic optimization.
Explore our complete Peptide Stacking Guide for more combinations and safety considerations.
Reconstitution
| Typical Vial Size | 10mg |
|---|---|
| BAC Water | 1-2ml per 10mg vial |
| Storage | Refrigerate at 2-8°C after reconstitution; protect from light (photosensitive) |
| Shelf Life | 28 days refrigerated; protect from light exposure as peptide is light-sensitive |
Need exact syringe measurements?
Amino Acid Sequence
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH
Side Effects & Safety
- Nausea and vomiting
- Facial flushing
- Spontaneous erections (priapism risk)
- Darkening of existing moles and freckles
- Systemic toxicity with overdose including sympathomimetic symptoms
- Rhabdomyolysis reported
- Renal dysfunction
- Potential cerebral edema
- Risk of skin cancer acceleration (theoretical)
Safety & Contraindications
This information is for educational purposes only. Consult a qualified healthcare provider before using any peptide.
History of Melanoma or Atypical Nevi
Cardiovascular Disease
Pregnancy / Lactation
Bleeding Disorders
Active Skin Infection at Injection Site
Drug Interactions
- Antihypertensive Agents:
FDA Safety Information
FDA Category 2 concerns: immunogenicity, melanoma reports, PRES, sympathomimetic toxidrome, priapism.
Pharmacokinetics
| Half-Life | ~30-60 minutes |
|---|---|
| Storage | Store lyophilized peptide at -20°C (long-term) or 2-8°C (short-term, under 30 days). Reconstituted: refrigerate at 2-8°C and use within 28-30 days. Protect from light. Do not freeze reconstituted solution. |
Synergistic Compounds
The following compounds have been studied alongside Melanotan II for potential complementary or synergistic effects:
Learn More
References & Further Reading
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