Quick Facts

Chemical Name
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2
Also Known As
MT-II, MT2
Category
Skin & Hair
Administration
Subcutaneous injection, typically in the evening to sleep through initial nausea

What is Melanotan II?

Melanotan II is a synthetic cyclic peptide analog of alpha-melanocyte-stimulating hormone (α-MSH). Originally developed at the University of Arizona for skin cancer prevention through sunless tanning, it was found to have multiple effects including enhanced libido, reduced appetite, and improved body composition. While it never received FDA approval, it remains widely used in research and bodybuilding communities for tanning and its other effects.

How Does Melanotan II Work?

Melanotan II activates melanocortin receptors, particularly MC1R (skin pigmentation), MC3R and MC4R (sexual function and appetite), and MC5R (exocrine function). By stimulating MC1R in melanocytes, it increases melanin production independent of UV exposure. Its effects on MC3R and MC4R in the hypothalamus influence sexual arousal and appetite regulation. The peptide's broad receptor activation accounts for its multiple effects but also its side effect profile.

Research-Backed Benefits

Skin Tanning

Strong Evidence

Stimulates melanin production for a natural-looking tan with reduced UV exposure needed.

Libido Enhancement

Strong Evidence

Increases sexual desire and function in both men and women through central melanocortin receptor activation.

Appetite Suppression

Moderate Evidence

May reduce hunger and food intake through MC4R activation in the hypothalamus.

Fat Loss Support

Emerging Research

Research suggests potential for reducing body fat, partly through appetite effects and possibly direct metabolic actions.

Dosage Guidelines

Disclaimer: This content is for educational purposes only. Peptides are research compounds not approved by the FDA for human use. Always consult with a qualified healthcare provider.

Typical Range
0.25-0.5 mg initially, maintenance 0.5-1 mg
Frequency
Daily during loading, then 1-2 times weekly for maintenance
Duration
2-3 week loading phase, then as needed for maintenance

Start low due to nausea. Some UV exposure still needed to develop tan. Effects are cumulative.

Side Effects & Safety

  • Nausea (especially initially)
  • Facial flushing
  • Spontaneous erections (in men)
  • Darkening of moles (monitor carefully)
  • Fatigue and yawning
  • Long-term effects on moles unknown

Frequently Asked Questions

Initial skin darkening may be noticed within 1-2 weeks. A full tan typically develops over 3-4 weeks of use combined with some UV exposure to activate the melanin.
MT-II has not been approved by any regulatory agency due to safety concerns, particularly regarding long-term effects on moles and potential melanoma risk. Users should monitor moles carefully and consult dermatologists.
Yes, some UV exposure is needed to activate the increased melanin. However, you can achieve a tan with much less sun exposure than normal.
MT-I (Afamelanotide) is more selective for tanning with less sexual effects. MT-II has broader receptor activity affecting libido, appetite, and tanning.

References

  1. Dorr RT, et al. "Melanotan II tanning effects." Life Sci, 1996. PMID: 8769364
  2. Wessells H, et al. "MT-II sexual effects." J Urol, 2000. PMID: 10711309

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