Sexual Health

Melanotan II

Also known as: MT-II, MT2, Melanotan 2

Research
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Key Facts: Melanotan II

Category
Sexual Health
FDA Status
Not FDA Approved
Clinical Status
Not approved - Research discontinued due to side effects. FDA Category 2 (restricted; expected to remain restricted due to melanoma risk and other safety concerns)
Administration
Subcutaneous injection
Typical Dose
250-500 mcg daily (loading), then 500-1,000 mcg weekly (maintenance)
Frequency
Daily during loading (1-2 weeks), then weekly maintenance
Duration
Loading phase 2-3 weeks, then maintenance
Also Known As
MT-II, MT2, Melanotan 2

Mechanism of Action

Melanotan II is a non-selective agonist of the melanocortin receptors, hitting MC1, MC3, MC4, and MC5. Switching on MC1 receptors in skin pigment cells ramps up melanin production, which is the tanning effect. Its sexual effects come from a completely different site: activating MC4 receptors in the brain triggers the neural circuits behind sexual arousal and desire, independent of the vascular plumbing that Viagra-type drugs target. Because it activates so many receptors at once rather than just one, it produces a broad spread of effects and side effects.

Research Summary

Human evidence for Melanotan II is real but narrow and mostly old. A published clinical study in men with organic erectile dysfunction found that the alpha-MSH analog produced subjectively reported erections after 12 of 19 injections versus only 1 of 21 placebo doses, with longer periods of penile rigidity and increased sexual interest, alongside frequent nausea and yawning. That erectogenic finding is exactly what spun off bremelanotide as a regulated drug. The tanning use, by contrast, has no large safety trials behind it, and dermatology sources flag serious concerns: new or changing moles and melanoma reports, uneven or permanent darkening, nausea, and the obvious dangers of injecting an unregulated powder of uncertain purity. Bottom line: it clearly does something at the receptor level, but Melanotan II as sold is an unapproved compound with a thin safety record and known risks, distinct from its approved descendants afamelanotide and bremelanotide.

Trial Progress:Preclinical
Pre
I
II
III
IV
FDA

Dosing Information

Limited Research·Limited formal studies available

Typical Dosing

Community experience

Common Dose

250-500 mcg daily (loading), then 500-1,000 mcg weekly (maintenance)

Range

100-1,000 mcg per dose

Frequency

Daily during loading (1-2 weeks), then weekly maintenance

Start very low to assess tolerance. Causes tanning, may increase libido. Nausea common initially. UV exposure needed for tanning effect.

Research Dosing

Scientific studies

Doses observed in research and user reports

Doses from Studies

Maintenance: 500mcg weekly after loading

Research Literature - Observed in studies

Duration

Loading phase 2-3 weeks, then maintenance

Administration

Subcutaneous injection

Timing & Administration

Best Time to Take

Evening or before sun exposure

Once daily during loading, then maintenance

Food Recommendation

With or without food

Why This Timing?

Melanotan II is used for tanning and libido. Evening use minimizes visible flushing; pre-sun exposure maximizes tanning.

Possible Side Effects

Not everyone experiences these effects. Individual responses vary based on dosage, duration, and personal factors.

  • Nausea (common)
  • Facial flushing
  • Fatigue
  • Spontaneous penile erections
  • Darkening of skin and moles
  • Priapism (requires emergency care)
  • Association with melanoma risk
  • May trigger histamine release - use caution with MCAS or histamine sensitivity
  • ILLEGAL in US, UK, Australia - not FDA approved

References

Research This Peptide Further

Frequently Asked Questions

What does Melanotan II do?

Melanotan II is a synthetic copy of alpha-melanocyte-stimulating hormone (alpha-MSH), nicknamed the tanning peptide because it darkens skin without much sun. It also triggers erections and can blunt appetite, which is why it became the template for the FDA-approved drug bremelanotide (PT-141). Melanotan II itself is not approved by the FDA or EMA and is sold only as an unregulated research chemical.

How does Melanotan II work?

Melanotan II is a non-selective agonist of the melanocortin receptors, hitting MC1, MC3, MC4, and MC5. Switching on MC1 receptors in skin pigment cells ramps up melanin production, which is the tanning effect. Its sexual effects come from a completely different site: activating MC4 receptors in the brain triggers the neural circuits behind sexual arousal and desire, independent of the vascular plumbing that Viagra-type drugs target. Because it activates so many receptors at once rather than just one, it produces a broad spread of effects and side effects.

Is Melanotan II FDA approved?

No, Melanotan II is not currently FDA approved. Current status: Not approved - Research discontinued due to side effects. FDA Category 2 (restricted; expected to remain restricted due to melanoma risk and other safety concerns)

What are the side effects of Melanotan II?

Reported side effects include: Nausea (common), Facial flushing, Fatigue, Spontaneous penile erections, Darkening of skin and moles. Individual responses vary based on dosage, duration, and personal health factors.

What is the typical dose of Melanotan II?

Community-reported common dose: 250-500 mcg daily (loading), then 500-1,000 mcg weekly (maintenance) (Daily during loading (1-2 weeks), then weekly maintenance). Range: 100-1,000 mcg per dose. Administration: Subcutaneous injection. Community-reported doses. Not medical advice. Consult healthcare provider.

Related Peptides

Peptides commonly compared with Melanotan II or used in similar applications.

PT-141

FDA

PT-141, generic name bremelanotide and sold as Vyleesi, is a melanocortin peptide and a cyclic analog of alpha-MSH that works in the brain to boost sexual desire. It is genuinely FDA approved: in June 2019 it became the first on-demand treatment for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. It is also used off-label for low libido and erectile dysfunction in men.

Sexual Health

TB-500

Preclinical

TB-500 is a synthetic peptide that copies the active region of thymosin beta-4, a natural protein that controls how cells build and move their internal skeleton. Most TB-500 products reproduce the short LKKTETQ sequence (residues 17 to 23) responsible for binding actin and driving cell migration, which is why it gets marketed for tendon, muscle, and wound repair. Here is the honest part: there are essentially no completed human trials of the TB-500 fragment itself, and almost all the human clinical data is for the full-length thymosin beta-4 molecule, which is related but not the same thing.

Healing

Tirzepatide

FDA

Tirzepatide is a single peptide that activates two receptors at once: GIP and GLP-1, the two main incretin hormones your gut releases after eating. It is FDA-approved as Mounjaro for type 2 diabetes and as Zepbound for chronic weight management and obstructive sleep apnea, and it has produced the largest weight-loss numbers of any approved drug to date. Like semaglutide, this is a heavily trialed, fully approved medicine, not a gray-market research compound.

Weight Loss

Ipamorelin

Clinical Trials

Ipamorelin is a synthetic pentapeptide growth hormone secretagogue developed by Novo Nordisk and derived from GHRP-1. It is researched mainly for stimulating the body's own growth hormone (GH) release, and was studied in humans primarily for postoperative ileus and gut motility rather than anti-aging. It is not an approved drug anywhere: it reached Phase II trials, was discontinued for insufficient efficacy, and is now sold only as a research chemical.

Growth Hormone

CagriSema

Clinical Trials

CagriSema is a once-weekly injectable that pairs two drugs in one shot: semaglutide (a GLP-1 receptor agonist, the molecule behind Ozempic and Wegovy) and cagrilintide (a long-acting amylin analog). It is being developed by Novo Nordisk for obesity and type 2 diabetes, and in 2025 it cleared its phase 3 REDEFINE trials. It is not yet approved by the FDA, though regulatory filings are underway.

Weight Loss

Glow Protocol

Preclinical

GLOW (sometimes sold as Glow Blend) is a marketing name for a three-peptide cocktail: GHK-Cu (a copper-binding tripeptide), BPC-157, and TB-500. It is pitched for skin rejuvenation, collagen support, and tissue healing, usually as a single injectable blend from compounding clinics or research suppliers. None of the three peptides is FDA-approved for these uses, and the GLOW combination has never been studied as a product in any clinical trial.

Peptide Blend

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