Quick summary
Melanotan II is a synthetic alpha-MSH analog that induces skin tanning without UV exposure by activating MC1R. It also affects sexual arousal and appetite through non-selective melanocortin receptor binding, and is one of the most widely used cosmetic peptides despite lacking regulatory approval.
Overview
Melanotan II is a synthetic analog of alpha-melanocyte stimulating hormone (α-MSH) that stimulates melanogenesis (skin tanning) and has secondary effects on sexual arousal and appetite suppression. It was originally developed at the University of Arizona as a potential sunless tanning agent to reduce skin cancer risk. It is one of the most widely used cosmetic peptides despite lacking regulatory approval.
Mechanism of action
Melanotan II binds non-selectively to melanocortin receptors MC1R through MC5R. MC1R activation stimulates melanocytes to produce eumelanin (dark pigment), producing a tan without UV exposure. MC4R activation affects sexual arousal (which led to the development of PT-141). MC3R/MC4R activation suppresses appetite. The broad receptor binding profile explains the diverse effects and side effect profile.
Dosing protocols
| Purpose | Route | Dosage | Frequency | Notes |
|---|---|---|---|---|
| tanning | subcutaneous | 250–500 mcg | daily | Loading phase: 250-500mcg daily for 2-3 weeks. Maintenance: 250mcg 1-2x/week. Start low to assess nausea tolerance. |
Dosing information is for educational purposes only. Consult a qualified healthcare professional before using any peptide.
Research summary
University of Arizona studies demonstrated significant increases in skin pigmentation in fair-skinned individuals with reduced UV exposure requirements. Phase II trials showed tanning effects within 5-7 days. Sexual arousal effects in both men and women were a consistent finding. Side effects include nausea (especially initial doses), facial flushing, fatigue, and potential for new or changed moles. Long-term safety data is limited.[1][2][3][4]
Evidence grading
Each claimed benefit is graded by the strength of available evidence. Grades reflect study quality, not effect size.
Strong = multiple RCTs · Moderate = limited trials or observational · Preliminary = animal or in vitro only · Insufficient = anecdotal or no published data
Side effects
Side effects vary by individual. This is not an exhaustive list. Report unusual symptoms to a healthcare professional.
Common stacks
Peptides commonly paired with Melanotan II for synergistic effects.
Legal status
Not FDA-approved. Sold as a research peptide. Regulatory agencies (FDA, TGA, MHRA) have issued warnings against its cosmetic use. Not scheduled or banned in most jurisdictions.
Sourcing & access
Research compound
Melanotan II is classified as a research compound. Regulatory status varies by jurisdiction. Always verify current legal status and source from vendors providing third-party certificates of analysis (COA).
Frequently asked questions
Melanotan II is a synthetic peptide analog of alpha-melanocyte stimulating hormone developed at the University of Arizona. It stimulates melanin production for skin tanning and has secondary effects on sexual arousal and appetite suppression.
Long-term safety data is limited. Common side effects include nausea (especially with initial doses), facial flushing, fatigue, and potential changes to moles. Regulatory agencies including the FDA, TGA, and MHRA have issued warnings against its cosmetic use.
Phase II trials showed tanning effects within 5 to 7 days. A loading phase of 250 to 500 mcg daily for 2 to 3 weeks is typical, followed by maintenance doses of 250 mcg once or twice per week.
Melanotan II is not FDA-approved and is sold as a research peptide. It is not scheduled or banned in most jurisdictions, but regulatory agencies have warned against its cosmetic use. It is expected to remain on the FDA Category 2 list.
Melanotan II can cause new moles to appear or existing moles to darken due to its activation of melanocytes. Users are advised to monitor any mole changes carefully, as increased melanocytic activity may theoretically mask or complicate skin cancer screening.
Research references
- Evaluation of Melanotan-II, a Superpotent Cyclic Melanotropic Peptide in a Pilot Phase-I Clinical StudyPubMed
- Evaluation of the Safety, Pharmacokinetics and Pharmacodynamic Effects of Subcutaneously Administered PT-141, a Melanocortin Receptor Agonist, in Healthy Male Subjects and in Patients with an Inadequate Response to ViagraPubMed
- Effect of MELANOTAN, [Nle4,D-Phe7]-alpha-MSH, on Melanin Synthesis in Humans with MC1R Variant AllelesPubMed
- Melanotan II User Experience: A Qualitative Study of Online Discussion ForumsPubMed