Is Melanotan II safe?

Melanotan II has not been approved for human use due to safety concerns. Known risks include effects on moles, nausea, and cardiovascular effects. The theoretical risk of stimulating melanocyte growth remains a concern. Long-term safety data is lacking.

Is Melanotan II legal in the UK?

Melanotan II is classified as a prescription-only medicine in the UK due to its pharmacological effects, despite not being licensed. It is illegal to sell for human use, and the MHRA advises against its use. Possession for personal use is not illegal.

Does Melanotan II cause cancer?

There is no definitive evidence that Melanotan II directly causes melanoma. However, it stimulates melanocytes and affects existing moles, raising theoretical concerns. Anyone with melanoma risk factors should absolutely avoid this peptide.

What is the difference between Melanotan I and Melanotan II?

Melanotan I (afamelanotide) is a linear peptide primarily affecting pigmentation and is now approved as Scenesse for certain conditions. Melanotan II is a cyclic peptide with additional effects on sexual function and appetite due to broader melanocortin receptor activity.

Fact-checked by the Peptide Authority Editorial Board · Last reviewed: 1 February 2026

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Sexual Health & Tanning•Updated 2026-02-01•6 min read

What Is Melanotan II? Benefits, Research & Safety

A synthetic analogue of alpha-melanocyte stimulating hormone researched for tanning effects and sexual function enhancement.

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Also known as:

MT-2

MT-II

Melanotan 2

DAnimal/cell evidence onlyUK: Unlicensed (UK)WADA: Sport status unclear

UK summary: Not a licensed UK medicine. Treated by the MHRA as a prescription-only medicine on the basis of its pharmacological effects. UK sale for human use is unlawful; the MHRA has actively warned the public against using it.

Quick Facts

Overview

Melanotan II (MT-II) is a synthetic cyclic heptapeptide analogue of alpha-melanocyte stimulating hormone (α-MSH). Developed at the University of Arizona in the 1980s, this peptide was initially investigated as a potential sunless tanning agent to reduce skin cancer risk by providing protective melanin pigmentation without UV exposure. During clinical research, scientists discovered that Melanotan II produced significant effects beyond skin pigmentation, including pronounced effects on sexual arousal and erectile function. This led to the development of a more targeted derivative, PT-141 (bremelanotide), which focuses specifically on the sexual function aspects. Melanotan II works by activating melanocortin receptors, particularly MC1R (involved in pigmentation) and MC3R/MC4R (involved in sexual function and energy homeostasis). This multi-receptor activity accounts for its diverse biological effects. The peptide has gained notoriety in the tanning community despite never receiving regulatory approval for any indication. It remains a research compound associated with significant safety concerns and is classified as a prescription-only medicine in many jurisdictions due to its pharmacological activity. Melanotan II is not approved for human use by any major regulatory authority including the MHRA, FDA, or EMA. Its use carries documented risks and should only be considered under appropriate medical supervision.

Evidence standards summary

Melanotan II — evidence and risk at a glance

Twenty standard modules scored against the Peptide Authority evidence grading methodology. Missing modules indicate the field has not yet been characterised editorially — treat absences as uncertainty rather than reassurance.

01Evidence snapshot

DAnimal/cell evidence onlyOverall grade against our evidence grading methodology.

Not a licensed UK medicine. Treated by the MHRA as a prescription-only medicine on the basis of its pharmacological effects. UK sale for human use is unlawful; the MHRA has actively warned the public against using it.

02Human evidence grade

DAnimal/cell evidence onlyStrength of evidence from published human trials.

03Preclinical evidence grade

CLimited human evidenceAnimal-model and in-vitro evidence quality.

04Regulatory status

UK: Not licensed for any indication. Classified as a prescription-only medicine (POM) due to pharmacological activity. MHRA has issued warnings against use.
EU: Not approved for any indication. Regulatory warnings issued in multiple member states.
Notes: Melanotan II is not approved anywhere in the world for any indication. It is banned by WADA in sport. Regulatory agencies including MHRA, FDA, EMA, and TGA have issued explicit warnings about its use. Products sold are unregulated and may contain contaminants.

05Approved medical uses

None for cosmetic tanning. Afamelanotide (Scenesse) is a separately-licensed product for the rare condition erythropoietic protoporphyria (EPP) via specialist NHS centres — not the consumer melanotan market.

06Unapproved / promotional claims

Safe alternative to sunbeds
Natural tan with no skin-cancer risk
Bronze with no other effects

07Common internet claims

Use the nasal spray for safer dosing
Pair with sunbed sessions for ‘rapid bronze’
Pharma-grade vials are safe at any dose

08Claim vs evidence

Claim	Evidence	Human evidence?	Regulatory concern	Safer wording
“Safe sunless tanning”	E	No	High	Documented adverse effects include nausea, blood-pressure changes, and effects on moles. No UK regulator has assessed it as safe for cosmetic tanning.
“Prevents skin cancer by replacing UV exposure”	E	No	High	There is no evidence Melanotan II reduces skin-cancer risk in humans, and effects on existing moles are a concern.
“Improves libido and erectile function”	C	Limited	High	Some preclinical and limited human signals exist; the derivative PT-141 (bremelanotide) is the licensed melanocortin product for sexual dysfunction in some jurisdictions, not Melanotan II.
“Sold legally as 'research only'”	E	No	High	MHRA treats Melanotan II as a POM; 'research only' labelling does not make sale to consumers for human use lawful.

09Safety uncertainty score

Very high

Effectively no human safety data; safety claims are extrapolations from animal work or anecdote.

10Known adverse signals

Mole changes and case reports of subsequent melanoma diagnoses
Severe nausea and vomiting
Cardiovascular events including hypertension and arrhythmia
Hospital admissions documented in UK case series
MHRA has issued repeated public-health warnings

11Drug-interaction uncertainty

Unknown

Drug-interaction picture not characterised for this peptide. Treat absence as uncertainty.

12Anti-doping status

WADA: Sport status unclearWADA strict-liability framing applies.

13UK legal position

UK: Unlicensed (UK)

Not licensed for any indication. Classified as a prescription-only medicine (POM) due to pharmacological activity. MHRA has issued warnings against use.

Read the full UK legal guide → Are peptides legal in the UK?

14EU legal position

Not approved for any indication. Regulatory warnings issued in multiple member states.

15What this page cannot tell you

Whether any dose of Melanotan II is safe for you — there is no lawful UK clinical guidance.
What is actually in a vial purchased outside the regulated chain.
Whether existing moles are at increased risk from MT-II exposure.
What the long-term cancer-related effects of repeated systemic alpha-MSH stimulation are.

16Last reviewed

Last reviewed: 1 February 2026

Next review due: 1 February 2027

Spotted an error or something out of date? Send a correction.

17Citation quality score

CLimited human evidenceQuality of the sources we cite, graded against the evidence grading methodology.

18Research gaps

No completed UK RCTs at any dose for cosmetic tanning.
Long-term melanoma-incidence studies in users are lacking.
Pharmacokinetics in grey-market product is not characterised.

19Safer alternatives / established care pathways

Self-tanning lotions, mousses, and gradual tanning moisturisers.
Professional spray-tan services.
Sun-protective behaviour. The MHRA, NHS, and dermatology bodies advise against melanotan because the safety record is poor and no licensed alternative exists.

20Doctor discussion prompts

Questions to ask a qualified clinician

These are starter questions you can adapt for a GP, specialist, pharmacist, or anti-doping advisor. The aim is to help you have a better-informed conversation — not to replace one.

What does the MHRA say about Melanotan II for cosmetic tanning?
What documented side effects should I look out for?
Are existing moles a particular concern for me?
If I'm interested in PT-141 for sexual dysfunction, is there a licensed alternative?
How should I report a side effect or suspected adverse event?

Discovery & History

Melanotan II was developed in the 1980s at the University of Arizona by researchers led by Dr. Victor Hruby. The initial goal was to create a synthetic melanotropin that could stimulate melanin production and provide protective tanning without UV exposure, potentially reducing skin cancer risk. The research built upon earlier work with Melanotan I (afamelanotide), a linear α-MSH analogue. Melanotan II was designed as a cyclic peptide for improved stability and potency, with modifications to enhance resistance to enzymatic degradation. During Phase I and II clinical trials investigating tanning effects, researchers observed unexpected side effects including spontaneous penile erections and increased sexual arousal in both male and female subjects. These findings led to recognition of the peptide's effects on central melanocortin receptors involved in sexual function. Following these discoveries, research focus split: some work continued on the tanning aspects while pharmaceutical development pivoted toward isolating the sexual function effects. This led to the creation of PT-141 (bremelanotide), a derivative specifically targeting sexual dysfunction. Despite promising research, Melanotan II never completed regulatory approval processes. Concerns about long-term safety, particularly regarding potential effects on existing moles and theoretical melanoma risk, contributed to the decision not to pursue full development for tanning indications. The peptide became widely available through unregulated channels and gained popularity in the tanning community, leading to regulatory warnings and enforcement actions in multiple countries.

Mechanism of Action

Melanotan II exerts its biological effects through activation of melanocortin receptors (MCRs), a family of G protein-coupled receptors with diverse physiological roles: **MC1R Activation (Pigmentation)** Activation of melanocortin-1 receptors on melanocytes stimulates the production and release of eumelanin, the dark pigment responsible for skin tanning. This occurs through: - Increased tyrosinase activity (rate-limiting enzyme in melanin synthesis) - Enhanced transfer of melanosomes to keratinocytes - Shift from pheomelanin (red/yellow) to eumelanin (brown/black) production **MC3R and MC4R Activation (Sexual Function)** These central nervous system receptors mediate effects on sexual arousal and function: - MC4R activation in hypothalamic areas triggers downstream signaling affecting arousal - Unlike PDE5 inhibitors, the mechanism is centrally mediated, not peripheral vascular - Effects occur in both males and females through distinct pathways - Involves modulation of dopaminergic and oxytocinergic systems **MC3R and MC4R (Metabolic Effects)** These receptors also influence energy homeostasis and appetite: - May reduce appetite in some individuals - Affects energy expenditure - Complex interactions with leptin and other satiety signals **Other Receptor Effects** Melanotan II has some activity at other melanocortin receptors, contributing to its complex pharmacological profile and side effect spectrum.

Researched Benefits

Based on preclinical and clinical research findings:

1
Increased skin pigmentation without UV exposure
2
Potential protective melanin against UV damage
3
Enhanced erectile function in males
4
Increased sexual arousal in both sexes
5
Possible appetite-suppressing effects
6
Accelerated tanning response to minimal UV exposure

Claim vs Evidence

How popular claims about Melanotan II stack up against the current research, graded using our public evidence grading methodology.

Claim	Evidence	Human evidence?	Regulatory concern	Safer wording
“Safe sunless tanning”	E	No	High	Documented adverse effects include nausea, blood-pressure changes, and effects on moles. No UK regulator has assessed it as safe for cosmetic tanning.
“Prevents skin cancer by replacing UV exposure”	E	No	High	There is no evidence Melanotan II reduces skin-cancer risk in humans, and effects on existing moles are a concern.
“Improves libido and erectile function”	C	Limited	High	Some preclinical and limited human signals exist; the derivative PT-141 (bremelanotide) is the licensed melanocortin product for sexual dysfunction in some jurisdictions, not Melanotan II.
“Sold legally as 'research only'”	E	No	High	MHRA treats Melanotan II as a POM; 'research only' labelling does not make sale to consumers for human use lawful.

Theoretical Dosing & Protocols

⚠️ Educational Only: The following information is derived from research literature and is not a prescription or recommendation. No standardised human dosing exists. Always consult a qualified healthcare professional.

Theoretical Dosage	0.25-0.5 mg initially, titrating up to 0.5-1 mg (from research literature)
Frequency	Daily during loading phase, then maintenance 1-2 times weekly
Duration	Loading phase typically 2-4 weeks; maintenance ongoing
Notes	⚠️ Melanotan II is not approved for human use. These protocols are extrapolated from research literature and anecdotal reports only. Significant safety concerns exist. Medical supervision is essential if considering any melanotropic peptide.

Administration Routes

Routes studied in research settings (educational only):

Subcutaneous injection (most common research route)
Nasal spray (less bioavailable; historically marketed illegally)

Half-Life	Stability
Approximately 1 hour in circulation	Lyophilised powder stable when stored at -20°C; reconstituted solution should be refrigerated and used promptly

Safety Profile & Known Risks

Commonly Reported Side Effects

Nausea and vomiting (especially early doses)
Facial flushing
Fatigue and lethargy
Spontaneous erections
Increased libido
Injection site reactions
Headache

Rare Risks & Concerns

Changes to existing moles (darkening, growth)
New mole development (new nevi)
Theoretical melanoma concern with stimulation of melanocytes
Cardiovascular effects (elevated blood pressure)
Priapism (prolonged erection)
Long-term effects on pigmentation unknown
Potential psychological effects on body image

Contraindications

Personal or family history of melanoma
Multiple atypical moles or dysplastic naevus syndrome
Pregnancy and breastfeeding
Cardiovascular disease
Current skin cancers or suspicious lesions
Children and adolescents
Autoimmune skin conditions

UK & EU Regulatory Context

🇬🇧 United Kingdom

Not licensed for any indication. Classified as a prescription-only medicine (POM) due to pharmacological activity. MHRA has issued warnings against use.

🇪🇺 European Union

Not approved for any indication. Regulatory warnings issued in multiple member states.

Melanotan II is not approved anywhere in the world for any indication. It is banned by WADA in sport. Regulatory agencies including MHRA, FDA, EMA, and TGA have issued explicit warnings about its use. Products sold are unregulated and may contain contaminants.

Clinical Studies Summary

Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction.

The erectogenic properties of Melanotan II are not limited to cases of psychogenic erectile dysfunction; men with a variety of organic risk factors developed penile erections. The finding of increased sexual desire warrants further investigation of centrally acting agents on disorders of sexual desire.

Urology. 2000View on PubMed

Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II.

Our findings warrant further investigation of melanocortin agonists and antagonists on penile erection. International Journal of Impotence Research (2000) 12, Suppl 4, S74-S79.

Int J Impot Res. 2000View on PubMed

Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study.

Melanotan-II is a potent initiator of erections in men with psychogenic erectile dysfunction and has manageable side effects at a dose of 0.025 mg./kg.

J Urol. 1998View on PubMed

Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study.

The recommended single MT-II dose for future Phase I studies is 0. 025 mg/kg/day.

Life Sci. 1996View on PubMed

Melanotan II: a possible cause of renal infarction: review of the literature and case report.

We present a review of Melanotan II and the possible effects of this drug on the kidneys by including a case of a renal infarction most likely attributed to Melanotan II. In the mechanism of renal injury with Melanotan II, thrombotic pharmacological influence and possible direct toxic effect on renal parenchyma must be considered.

CEN Case Rep. 2020View on PubMed

Falsification of biotechnology drugs: current dangers and/or future disasters?

Next, we describe the identification strategy utilised by our lab to identify the API in falsified biotherapeutics, followed by a discussion of the putative hazards due to impurities and contaminations that were found or could be encountered in falsified biotherapeutics. Finally, we terminate with an educational prediction of what may happen in the future and possible ways to counteract putative future disasters.

J Pharm Biomed Anal. 2018View on PubMed

Registered Trials & Regulatory Status

Registered trials

Currently recruiting

Furthest phase

Phase 2

Approved product

Melanotan II (MT-II) as an Adjunct to NB-UVB Phototherapy for Repigmentation in Stable Nonsegmental Vitiligo

PHASE2

Status: Recruiting · 60 participants · Hudson Biotech

Conditions: NonSegmental Vitiligo, Nonsegmental Vitiligo (Stable)

No results postedNCT07437560

Psychological Effects of Methylenedioxymethamphetamine (MDMA) When Administered to Healthy Volunteers (MT-2)

PHASE1

Status: Withdrawn · Resilient Pharmaceuticals

Conditions: Psychological Effects of Study Drug

No results postedNCT04073433

Adverse event reports (FDA FAERS)

Not applicable: no licensed product contains this peptide, so it is not reported through FAERS. This is an absence of surveillance, not evidence of safety.

Source: ClinicalTrials.gov and openFDA. Updated automatically.

Looking for Melanotan II?

Source research-grade Melanotan II from a trusted UK supplier — third-party tested with certificate of analysis.

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Frequently Asked Questions

Questions to ask a qualified clinician about Melanotan II

These are starter questions you can adapt for a GP, specialist, pharmacist, or anti-doping advisor. The aim is to help you have a better-informed conversation — not to replace one.

What does the MHRA say about Melanotan II for cosmetic tanning?
What documented side effects should I look out for?
Are existing moles a particular concern for me?
If I'm interested in PT-141 for sexual dysfunction, is there a licensed alternative?
How should I report a side effect or suspected adverse event?

UK regulatory & safety context

Are peptides legal in the UK?

UK legal reference

Unlicensed peptide risks

Safety Centre guide

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