Skin & Cosmetic

Melanotan II

MT-2 · Melanotan 2

Cyclic α-MSH analog. Unapproved tanning research peptide. Not Scenesse (afamelanotide implant for EPP). MC1R tans; MC3/MC4 spillover is nausea, appetite, and unwanted erections - which is why PT-141 was split out. Mole darkening needs a dermatologist, not a peptide page.

Not FDA-approved - research chemical
Reviewed by CalcMyPeptide Editorial Team
Last updated: August 2026Evidence: Low1 peer-reviewed citation
Typical research dose
250-500 mcg/day (loading)
Frequency
Daily (loading 2 weeks), then 1-2×/week maintenance
Half-life
~1 hour
Common vials
10 mg
CAS
121062-08-6
Molecular weight
1024.18 g/mol

Use-case scores

0–10 against the evidence we have, not a gym ranking. Hidden domains do not apply here.

  • Skin / cosmetic3.5/10

    Melanogenesis in humans is real and messy (moles, nausea). Community/unapproved: ceiling 4. Not Scenesse (afamelanotide) for EPP.

  • Sexual / hormonal3/10

    MC3/MC4 spillover is why PT-141 exists. Uncontrolled erections are an adverse effect, not an ED indication.

Compound card

Class
Non-selective α-MSH analog (not afamelanotide / Scenesse)
Formula
C50H69N15O9
Status
Not FDA-approved · research use
Dose it
10 mg + 2 mL BAC water → 5 mg/mL · 250 mcg ≈ 5 units (U-100)
Open in calculator

How it works

Melanotan II (MT-2) is a synthetic analog of alpha-melanocyte-stimulating hormone (α-MSH) that activates multiple melanocortin receptors. MC1R activation stimulates melanocytes to produce melanin, resulting in skin darkening (tanning) without UV exposure. MC3R/MC4R activation produces sexual arousal effects (the pathway that led to PT-141 development) and appetite suppression.

MT-2 is a non-selective melanocortin agonist, which means it produces multiple effects simultaneously: tanning, sexual function enhancement, and modest appetite reduction. The tanning effect is cumulative and persists for weeks to months after discontinuation.

Source: PMID: 10221658

Background & History

Melanotan II (MT-2) was developed at the University of Arizona in the 1980s–90s by Mac Hadley and colleagues seeking a method to induce melanogenesis without UV exposure for skin cancer prevention. It is a cyclic analog of alpha-MSH with 1000× greater potency than natural α-MSH at MC1R. Serendipitously, researchers discovered its potent sexual arousal and appetite suppression effects via MC4R activation. It has never received regulatory approval and is considered a research compound.

Research Use Cases

  • ✓Identity: unapproved α-MSH analog vs Scenesse (afamelanotide)
  • ✓Why tanning vials darken moles
  • ✓Not a melanoma-prevention protocol

Dosing

PhaseDoseFrequencyNotes
Loading Phase250 - 500 mcgDaily for 2 weeksInject before bed. Start at 100-250 mcg if nausea-sensitive during loading.
Maintenance Phase250 - 500 mcg1-2x per weekBrief UV exposure (10-15 min) enhances melanin activation.

Administration

Route / form
Subcutaneous injection
Timing
Before bed to minimize nausea impact. Fasting not required.
Empty stomach?
No - Food timing is not critical.

Timeline

Week 1-2 (Loading)
Gradual skin darkening begins. Nausea most prevalent in this window.
Week 3-4
Visible tan develops. Nausea typically subsides as loading completes.
Maintenance
Tan sustained with 1-2 doses/week. Persists weeks-months after stopping.

Who it is for

Skin Tanning

High

Strong melanin production with or without UV. Tan persists after cycle ends.

Sexual Function Enhancement

Moderate

MC4R activation produces arousal effects - the pathway that led to development of PT-141.

Reconstitution

VialWaterConcentrationExample dose
10 mg lyophilized2 mL BAC5 mg/mL250 mcg loading on 10 mg / 2 mL (5 mg/mL) = 0.05 mL = 5 units on a U-100.

Change vial size or water volume? Open the reconstitution calculator.

Safety & Considerations

Research peptide - not FDA-approved. Monitor existing moles for changes. Common: nausea (loading phase), facial flushing, spontaneous erections (males). Not for use with history of melanoma.

Regulatory & Legal Status

FDA Status (US)
Research Only
WADA Status (2026)
Not Listed

Not currently on the WADA 2026 Prohibited List. Policies may change - verify before competition.

Classification

Research Chemical

US Compounding: Not eligible / not available

⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.

Limits of current evidence

  • Never approved. University of Arizona work is not a tanning NDA.
  • Not a melanoma-prevention protocol. New nevi need a dermatologist, not a peptide page.
  • PT-141 was split out to drop tanning. If the job is desire, that is the other leaf.

Verdict

MT-2 is a non-selective melanocortin agonist sold as a tanning research peptide. It is not FDA-approved. Scenesse is afamelanotide (MT-1 analog) for EPP. Do not launder that label onto this vial. Mole darkening is a monitoring problem, not a feature.

Interactions & Contraindications

MC1R activation causes mole darkening and new nevus formation - regular dermatological monitoring essential. Nausea common especially at higher doses. Spontaneous erections in men at standard doses. Do not use with cardiovascular disease. Use cautiously in patients with history of melanoma - theoretical risk of activating dormant melanocytes.

Synergies & Common Stacks

PT-141 is a more selective MC4R agonist derived from MT-2 with reduced melanogenic side effects - often preferred over MT-2 for pure sexual function goals.

Frequently Asked Questions

How does the Melanotan II loading phase work?▼
Loading: 250-500 mcg daily for 2 weeks. Maintenance: 250-500 mcg 1-2x weekly. Brief UV exposure (10-15 min) enhances activation.
Do I still need sun exposure with Melanotan II?▼
UV enhances MT-2 results but is not mandatory. Noticeable darkening can occur without UV over a full loading period.
Is Melanotan II the same as Melanotan I?▼
No. Melanotan I (Afamelanotide/Scenesse) is a selective MC1R agonist FDA-approved for erythropoietic protoporphyria. Melanotan II is non-selective, affecting tanning, sexual function, and appetite.

References

  1. Wessells H et al. “"Melanotan II: a review of the clinical and experimental findings".” International Journal of Impotence Research (2000). PMID: 10893508

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