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Melanotan II

Research Only

Melanocortin Peptides · Tanning & Sexual Function

Melanotan II is a synthetic analog of alpha-melanocyte-stimulating hormone (α-MSH) that stimulates melanin production (skin darkening), increases libido, and reduces appetite.

What is Melanotan II?

Melanotan II is a synthetic analog of alpha-melanocyte-stimulating hormone (α-MSH) that stimulates melanin production (skin darkening), increases libido, and reduces appetite. Originally developed at the University of Arizona for skin cancer prevention through tanning without UV exposure.

Also known as: MT-II, MT2

How Does Melanotan II Work?

Non-selectively activates melanocortin receptors (MC1R through MC5R). MC1R activation stimulates melanogenesis (tanning). MC4R activation increases sexual arousal and decreases appetite. MC3R activation affects energy homeostasis.

What is Melanotan II Used For?

  • Tanning without UV
  • Libido enhancement
  • Erectile dysfunction

Potential Side Effects

  • Nausea
  • Facial flushing
  • Spontaneous erections
  • Darkening of moles
  • Fatigue
  • Appetite suppression

Contraindications

  • Melanoma or history of melanoma
  • Pregnancy
  • Cardiovascular disease
  • Autoimmune conditions

FDA Legal Status

United States — FDA

Research Only

This peptide is currently investigational and not approved for clinical use.

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Frequently Asked Questions

Is Melanotan II safe?
Melanotan II has not been FDA-approved and carries several risks. It non-selectively activates multiple melanocortin receptors, causing unpredictable side effects. The most concerning is potential darkening of existing moles, which could mask melanoma changes. It is not recommended without medical supervision.
How is Melanotan II different from PT-141?
PT-141 (bremelanotide) was derived from Melanotan II but was refined to selectively target MC4R for sexual function. Melanotan II activates all melanocortin receptors non-selectively, causing tanning + libido effects + side effects. PT-141 is FDA-approved; Melanotan II is not.

Quick Facts

Legal Status (USA)
Research Only
Evidence Rating
CPreliminary Evidence (Mostly Preclinical)
Class / Subclass
Melanocortin Peptides / Tanning & Sexual Function
Administration
subcutaneous, nasal
Typical Dosage
0.25-0.5mg loading; 0.5mg before sun exposure
Half-Life
~36 hours
Year Discovered
1996

Sources

PubMed 15033225

Last updated: 2026-04-01

Sources & references

Primary sources used for the dosing, mechanism, side-effect, and regulatory claims on this page. Verify time-sensitive information (regulatory status, prescribing details) on the source before relying on it for medical decisions. See our disclaimer.

  1. PubMed PMID 15033225 — peer-reviewed primary literature on Melanotan II.
  2. FDA Federal Register — official notice record for FDA regulatory actions and Category 1 / 503A bulk-substance updates.