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melanocortin

Melanotan II

Also known as: MT-II, MT2, Melanotan 2, Barbie drug
FDA: NOT FDA-approved WADA: Prohibited at all times

Melanotan II is a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (alpha-MSH). Developed at the University of Arizona in the 1990s, it is a non-selective melanocortin receptor agonist that stimulates melanin production (tanning without UV exposure), suppresses appetite, and enhances sexual arousal/erectile function. Despite never receiving FDA approval, Melanotan II has become one of the most widely used illicit peptides globally, marketed online as a tanning agent and colloquially known as the "Barbie drug." The FDA, TGA (Australia), and EMA have all issued warnings against its use. PT-141 (bremelanotide) is the FDA-approved derivative developed from Melanotan II, specifically targeting sexual

This content is for educational and research purposes only. VialBase does not provide medical advice. Consult a healthcare professional before using any peptide.

Molecular weight 1,024.18 Da
Half-life ~33 minutes
CAS number 121062-08-6
Route Subcutaneous · Intranasal subcutaneous preferred
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Mechanism

Non-selective melanocortin receptor agonist (MC1R-MC5R). Activates MC1R on melanocytes to stimulate eumelanin production (tanning), MC3R/MC4R in hypothalamus for appetite suppression and erectile function, and MC5R in exocrine glands.

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Dosing

DOSE RANGE 100–500 mcg
FREQUENCY 1x daily during loading; 1-2x weekly maintenance
CYCLE LENGTH Loading: 2-4 weeks; maintenance: indefinite (unregulated use)

Loading phase typically 250-500 mcg daily until desired pigmentation achieved, then maintenance 250-500 mcg 1-2x weekly. Start at 100 mcg to assess tolerance (nausea common). NOT recommended due to lack of safety data and regulatory warnings.

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Research summary

Study Type Year Key Finding
Recommended Tool Compounds for the Melanocortin Receptor (MCR) G Protein-Coupled Receptors (GPCRs) Pharmacology review 2024 Comprehensive characterization of melanocortin receptor subtypes MC1R-MC5R
Melanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma? Case report 2025 22-year-old female developed oral mucosal malignant melanoma after Melanotan II nasal spray use
Changes in Oral Mucosa Associated with Melanotan II Injections: A Case Report Case report 2026 Patient self-administered Melanotan II injections for 64 days for tanning
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Stacking & interactions

PT-141 is the sexual function-specific derivative; Melanotan II has broader/less selective activity

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Sourcing

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What bloodwork do I need?

Reference ranges are general guidelines. Consult your physician for interpretation.

PRE-CYCLE
  • CMP
  • CBC
  • Blood Pressure
  • Dermatologic exam (mole check)
DURING CYCLE
  • Blood Pressure
  • Visual mole monitoring
POST-CYCLE
  • CMP
  • Dermatologic exam
Safety & Regulatory Status
FDA STATUS NOT FDA-approved. Investigational only. FDA and TGA have issued warnings against use.
WADA STATUS Prohibited at all times (S2 - Peptide Hormones)

Regulatory status for Melanotan II may change. Verify current status with your jurisdiction before use. This is not legal or medical advice.

Frequently Asked Questions

What is Melanotan II?
Melanotan II is a synthetic cyclic peptide analog of alpha-melanocyte- stimulating hormone, developed at the University of Arizona in the 1990s. It is a non-selective melanocortin receptor agonist used illicitly to stimulate skin tanning without UV exposure, and is colloquially called the "Barbie drug." It is not FDA-approved, and the FDA and other regulators have issued warnings against its use.
How does Melanotan II work?
Melanotan II activates all five melanocortin receptor subtypes non-selectively. At MC1R on melanocytes it drives melanin (eumelanin) production, causing UV-independent skin darkening. At MC3R and MC4R in the hypothalamus it suppresses appetite and influences sexual arousal and erectile function. This broad, non-selective activity is also why it produces wide-ranging off-target effects.
How is Melanotan II dosed?
Melanotan II is not FDA-approved, and what follows describes documented patterns of use, not a recommendation. Reported use is a 100 mcg test dose to assess tolerance, a loading phase of about 250–500 mcg daily for 2–4 weeks, then maintenance of 250–500 mcg one to two times weekly, subcutaneously. Nausea is dose-limiting. Consult a clinician.
Is Melanotan II safe?
Safety is a significant concern and no long-term studies exist. Very common effects include nausea, facial flushing, fatigue, and spontaneous erections; existing moles may darken and new ones appear. Because it hyperactivates melanocytes, there is a mechanistically plausible melanoma concern, with documented case reports. Illicit products also show highly variable purity. Avoid with any melanoma history or atypical moles.
What does the research on Melanotan II show?
Formal human trials are limited; the published record is dominated by case reports and pharmacology reviews rather than safety or efficacy trials. A 2025 case report linked Melanotan II nasal spray to oral mucosal malignant melanoma in a young woman (Int J Oral Maxillofac Surg, PMID 40210573), and a 2026 case documented persistent oral mucosal pigmentation after 64 days of injections (Bonchev, Life, PMID 41752902).
Is Melanotan II FDA-approved or legal?
No. Melanotan II has never been FDA-approved; the FDA has issued import alerts and public warnings, and Australia's TGA and EU regulators warn against it. It is not eligible for pharmacy compounding and is marketed only as a "research chemical." WADA prohibits it at all times under category S2. Its FDA-approved selective derivative is PT-141 (bremelanotide).
What is the difference between Melanotan II and PT-141?
PT-141 (bremelanotide) is the FDA-approved derivative developed from Melanotan II, selectively targeting melanocortin receptors for sexual function (hypoactive sexual desire disorder). Melanotan II is non-selective across all five melanocortin receptors, which adds tanning, appetite, and broader off-target effects plus the associated safety burden. PT-141 is the regulated option when sexual function is the goal.

References

  1. Weirath NA, Haskell-Luevano C. Recommended Tool Compounds for the Melanocortin Receptor (MCR) G Protein-Coupled Receptors (GPCRs). ACS Pharmacology & Translational Science (2024). PMID: 39296259
  2. Yassin Alsabbagh A, Bhujel N, Singh RP. Melanotan II nasal spray: a possible risk factor for oral mucosal malignant melanoma?. International Journal of Oral and Maxillofacial Surgery (2025). PMID: 40210573
  3. Bonchev A. Changes in Oral Mucosa Associated with Melanotan II Injections: A Case Report. Life (Basel) (2026). PMID: 41752902