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
Primary route; half-life ~30 minutes; consistent dosing maintains melanocyte stimulation
Nasal Moderate
Intranasal spray available; lower bioavailability; useful at lower doses for sexual arousal effects
Read our full Routes of Administration Guide for detailed comparison of all delivery methods.
Stacking Protocols
Popular research stacks involving Melanotan II:
Tanning and Sexual Health Stack
Tanning optimization and sexual arousal enhancement
Both are melanocortin receptor agonists; can be combined but may amplify side effects (nausea, facial flushing); start at lower doses of each when combining.
Appetite Control Stack
Combined appetite suppression and lipolysis for body composition
Melanotan II reduces appetite via central MC4R; AOD-9604 activates peripheral fat cell lipolysis; complementary body composition effects.
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)
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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