Is MT-2 approved or legal to use?

No. MT-2 (Melanotan II) has never received regulatory approval from the FDA, EMA, or any other authority. It has never been submitted for drug approval. It is prohibited in competitive sport under WADA's S2 class. Research-grade material is sold as a laboratory compound, not for human consumption. Legal status for personal possession varies by jurisdiction.

How does MT-2 produce a tan?

MT-2 activates MC1R receptors on skin melanocytes, stimulating the production of eumelanin (dark brown/black pigment). This tanning response can occur with minimal or no UV exposure, though many community users combine it with limited sun or tanning-bed sessions. The effect reverses within weeks to months after stopping use.

What is the relationship between MT-2 and PT-141 (bremelanotide)?

PT-141 (bremelanotide, brand name Vyleesi) is a ring-opened metabolite derived from MT-2. It retains the melanocortin receptor activity relevant to sexual arousal but differs in its pharmacokinetic profile. Bremelanotide received FDA approval in 2019 for hypoactive sexual desire disorder (HSDD) in premenopausal women — the only melanocortin drug with this approval. MT-2 itself was never developed to that regulatory stage.

Why is mole monitoring important with MT-2?

MT-2 directly stimulates MC1R on melanocytes throughout the body, not just in the outer skin layer. This broad melanocyte activation has been associated in case reports and small series with darkening of existing moles, the sudden appearance of new atypical (dysplastic) moles, and at least several reported cases of melanoma developing from pre-existing lesions during or after use. Anyone who has used MT-2 should have any new or changing mole assessed by a dermatologist using ABCDE criteria (Asymmetry, Border, Colour, Diameter, Evolution). Individuals with pre-existing atypical moles or a personal/family history of melanoma are at substantially higher risk.

What are the main side effects?

The most common reported effects are nausea (the primary dose-limiting factor), facial flushing, fatigue, and yawning. Spontaneous penile erections in men are an expected pharmacological effect. Serious adverse events documented in case reports include priapism (prolonged erection requiring medical intervention), rhabdomyolysis, renal infarction, and melanoma. Severity and frequency of side effects increase with dose.

Is MT-2 the same as Melanotan I (afamelanotide)?

No. Melanotan I (afamelanotide, Scenesse) is a separate, more selective MC1R agonist delivered as an injectable implant. It is FDA-approved for increasing pain-free light exposure in adults with erythropoietic protoporphyria (EPP). Unlike MT-2, afamelanotide does not significantly activate MC4R and therefore does not produce erections or the broader neurological side-effect profile associated with MT-2.

Aesthetic

MT-2

Also known as: Melanotan II, Melanotan-2, MT-II, cyclo-[Nle4, D-Phe7]-α-MSH

A synthetic, non-selective melanocortin receptor agonist studied for skin tanning and erectile dysfunction; never approved by any regulatory authority and associated with...

Last updated July 11, 2026

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Overview

MT-2 (Melanotan II) is a cyclic heptapeptide and synthetic analogue of alpha-melanocyte-stimulating hormone (α-MSH), originally developed at the University of Arizona in the 1980s and 1990s as a potential drug for melanoma prevention through enhanced tanning without UV exposure. It differs from endogenous α-MSH by incorporating norleucine at position 4 and D-phenylalanine at position 7, modifications that dramatically increase potency and metabolic stability. Early human trials in the mid-1990s confirmed that subcutaneous injection produced skin darkening and, unexpectedly, provoked spontaneous penile erections — a side-effect profile that redirected the compound's research trajectory. The erection-inducing properties were studied in small double-blind crossover trials through the late 1990s and early 2000s, with generally positive findings for both psychogenic and organic erectile dysfunction. However, development of MT-2 itself was ultimately abandoned in favour of more selective analogues, most notably bremelanotide (PT-141 / Vyleesi), which is a ring-opened metabolite of MT-2 and the only melanocortin-based drug to reach FDA approval (for hypoactive sexual desire disorder in premenopausal women, 2019). MT-2 itself has never been submitted for regulatory approval and holds no marketing authorisation in any jurisdiction. It is prohibited in competitive sport under WADA's S2 (Peptide Hormones, Growth Factors, Related Substances) class. Material sold online is typically labelled "for research use only," and its quality is unregulated. Published case reports describe serious adverse events including dysplastic nevi eruption, melanoma arising from pre-existing moles, priapism requiring surgical intervention, rhabdomyolysis, and renal infarction. This entry summarises the available evidence and community-reported practice for reference only; it is not medical advice and does not endorse human use.

How it works

MT-2 is a broad-spectrum melanocortin receptor agonist with significant activity at MC1R, MC3R, MC4R, and MC5R, and negligible binding at the adrenal MC2R (ACTH receptor). This non-selective profile accounts for its wide and partly unpredictable range of effects. At MC1R, expressed on cutaneous melanocytes, MT-2 activates adenylyl cyclase via Gs coupling, raising intracellular cAMP and driving protein kinase A (PKA) phosphorylation of CREB. This cascade upregulates tyrosinase and related enzymes responsible for eumelanin (dark brown/black pigment) synthesis, producing skin darkening at doses that do not require ultraviolet light exposure. The magnitude of tanning depends substantially on the individual's baseline skin phototype. At MC4R, expressed throughout the central nervous system, MT-2 modulates hypothalamic and limbic circuits that influence sexual arousal, appetite, and autonomic tone. MC4R activation increases oxytocin release and intersects with dopaminergic pathways, producing pro-erectile signalling in the spinal cord and brain that is independent of peripheral vascular mechanisms — a fundamentally different pathway from PDE-5 inhibitors such as sildenafil. This central mechanism also accounts for the appetite-suppressive and metabolic effects reported in animal models. MC3R and MC5R co-activation by MT-2 contributes to its side-effect profile (nausea, flushing, yawning, fatigue) and likely underlies some of the compound's autonomic and metabolic actions. The broad receptor footprint distinguishes MT-2 from bremelanotide (PT-141), which is structurally similar but pharmacokinetically different, and from afamelanotide (Scenesse), an MC1R-selective agonist approved for erythropoietic protoporphyria that does not share MT-2's erection-inducing properties.

Researched effects

Clinical Induces skin tanning and increases cutaneous eumelanin production with or without UV exposure
Clinical Provokes penile erection and increases sexual desire in men with psychogenic erectile dysfunction
Clinical Initiates erections in men with organic erectile dysfunction risk factors
Preclinical Reduces appetite and food intake via central MC4R signalling
Preclinical Produces metabolic and anti-obesity effects in animal models
Anecdotal Increases female sexual arousal and libido (based on PT-141/bremelanotide analogy and community reports)

Evidence levels: Clinical (human trials) · Preclinical (animal/lab) · Anecdotal (community-reported).

Dosing reference

For research reference only — not a recommendation.

Clinical / studied dosing

No approved or established clinical dosing protocol exists for MT-2; it is not an approved drug anywhere. Published human research studies administered doses of 0.01–0.03 mg/kg subcutaneously (the 1996 Dorr phase I study used 0.01–0.03 mg/kg in 3 healthy volunteers; the Wessells erectile-function crossover studies used 0.025 mg/kg). These were single-dose or short-course research administrations, not therapeutic regimens. No Phase III trials were conducted. These doses are provided as a research summary, not as clinical guidance.

Community-reported dosing (anecdotal)

Anecdotal and research-reference only — not medical advice, not instruction, and not a recommended protocol. Community sources (online forums and vendor guides) commonly describe a loading phase of 0.25–0.5 mg subcutaneously per injection, administered once daily or every other day until a desired tan depth is achieved (typically 1–2 weeks), followed by a reduced maintenance frequency. Intranasal sprays are also reported but anecdotally considered less reliable in absorption. Reconstitution of lyophilised powder with bacteriostatic water is the standard preparation described. Community members frequently note that doses above ~0.5 mg markedly increase nausea. These figures reflect unverified self-reported practice and are provided for research context only.

Half-life: Not well characterised in humans. Animal and early human pharmacokinetic data suggest a short plasma half-life, typically cited at approximately 30 minutes to 1–2 hours for the parent peptide after subcutaneous injection. Biological effects (tanning, erection) outlast detectable plasma levels, indicating a pharmacokinetic–pharmacodynamic disconnect consistent with receptor-level downstream signalling persistence. Formal human PK studies are lacking.
Routes: subcutaneous, intranasal

Safety & side effects

MT-2 carries significant safety concerns and holds no regulatory approval in any jurisdiction. No large-scale or long-term human safety studies have been conducted. The following risks are documented in the published literature or represent substantiated regulatory concerns: Mole and melanoma risk: MT-2's direct stimulation of MC1R on melanocytes accelerates melanin production and has been associated with darkening of existing moles, development of new atypical (dysplastic) nevi, and — in published case reports — melanoma arising from pre-existing lesions during or shortly after use. A case involving a patient with familial atypical mole syndrome is documented in the peer-reviewed literature (PMC3663356). Anyone with a personal or family history of melanoma, or with many atypical moles, should be considered at substantially elevated risk. Regular dermatological screening, including ABCDE assessment of any new or changing moles, is strongly advisable if exposure has occurred. Dose-limiting side effects: Nausea is the most consistently reported and dose-limiting effect, occurring at doses as low as 0.01 mg/kg in some subjects; flushing, fatigue, and yawning are common. Spontaneous erections in men are not merely a benefit but an adverse event in non-therapeutic contexts. Serious adverse events in case reports: priapism requiring urological intervention, rhabdomyolysis, and renal infarction have each been described in case reports. Unregulated product quality: Research-grade material sold online is not pharmaceutical-grade, is not subject to GMP manufacturing controls, and may be impure, mislabeled, or contaminated. No consumer protection equivalent to drug-product standards applies. WADA prohibition: MT-2 is prohibited in competitive sport under the S2 class (Peptide Hormones, Growth Factors, Related Substances and Mimetics). Contraindications (based on mechanism and case data): use in individuals with personal or family history of melanoma, dysplastic nevi syndrome, current malignancy, or haematological disorders is particularly inadvisable. Pregnancy and breastfeeding use is unstudied and not recommended.

Research summary

The published human evidence for MT-2 is narrow but real: three to four controlled or semi-controlled clinical studies in small numbers of subjects (totalling fewer than 50 participants) confirm tanning efficacy at 0.01–0.03 mg/kg and erection-inducing effects in men with both psychogenic and organic erectile dysfunction. These outcomes are mechanistically coherent with the compound's MC1R and MC4R pharmacology. However, the clinical programme effectively stalled after these early-phase results. No Phase III trials were conducted, and MT-2 was never submitted for regulatory review. The compound's development was superseded by selective analogues: afamelanotide (Scenesse), an MC1R-selective implant, received EMA approval in 2014 for erythropoietic protoporphyria; bremelanotide (Vyleesi), a structurally related metabolite of MT-2, received FDA approval in 2019 for HSDD in premenopausal women. These approvals validate the underlying melanocortin biology but do not translate into safety or efficacy endorsement for MT-2 itself. The post-trial literature on MT-2 is dominated by case reports of serious adverse events: eruptive dysplastic nevi, melanoma, priapism, and rhabdomyolysis. A 2020 ScienceDirect-indexed report documents a priapism case following melanotan use requiring surgical intervention. A 2012 Dermatology Practical & Conceptual case (PMC3663356) describes significant melanocytic lesion changes in a high-risk teenager. Several additional case series in dermatology and urology journals document new or changed moles that included histologically confirmed dysplastic changes. The honest summary: MT-2 has pharmacologically confirmed tanning and erectile activity in small human studies, but it has never advanced beyond Phase I/II, is not approved by any regulator, carries documented melanoma/nevi risk that is mechanistically plausible and case-report confirmed, and its intended clinical applications have been handed to safer, more selective successors. It remains a gray-market research compound with a risk profile that outweighs its advantages given the availability of approved alternatives.

FAQ

Is MT-2 approved or legal to use?: No. MT-2 (Melanotan II) has never received regulatory approval from the FDA, EMA, or any other authority. It has never been submitted for drug approval. It is prohibited in competitive sport under WADA's S2 class. Research-grade material is sold as a laboratory compound, not for human consumption. Legal status for personal possession varies by jurisdiction.
How does MT-2 produce a tan?: MT-2 activates MC1R receptors on skin melanocytes, stimulating the production of eumelanin (dark brown/black pigment). This tanning response can occur with minimal or no UV exposure, though many community users combine it with limited sun or tanning-bed sessions. The effect reverses within weeks to months after stopping use.
What is the relationship between MT-2 and PT-141 (bremelanotide)?: PT-141 (bremelanotide, brand name Vyleesi) is a ring-opened metabolite derived from MT-2. It retains the melanocortin receptor activity relevant to sexual arousal but differs in its pharmacokinetic profile. Bremelanotide received FDA approval in 2019 for hypoactive sexual desire disorder (HSDD) in premenopausal women — the only melanocortin drug with this approval. MT-2 itself was never developed to that regulatory stage.
Why is mole monitoring important with MT-2?: MT-2 directly stimulates MC1R on melanocytes throughout the body, not just in the outer skin layer. This broad melanocyte activation has been associated in case reports and small series with darkening of existing moles, the sudden appearance of new atypical (dysplastic) moles, and at least several reported cases of melanoma developing from pre-existing lesions during or after use. Anyone who has used MT-2 should have any new or changing mole assessed by a dermatologist using ABCDE criteria (Asymmetry, Border, Colour, Diameter, Evolution). Individuals with pre-existing atypical moles or a personal/family history of melanoma are at substantially higher risk.
What are the main side effects?: The most common reported effects are nausea (the primary dose-limiting factor), facial flushing, fatigue, and yawning. Spontaneous penile erections in men are an expected pharmacological effect. Serious adverse events documented in case reports include priapism (prolonged erection requiring medical intervention), rhabdomyolysis, renal infarction, and melanoma. Severity and frequency of side effects increase with dose.
Is MT-2 the same as Melanotan I (afamelanotide)?: No. Melanotan I (afamelanotide, Scenesse) is a separate, more selective MC1R agonist delivered as an injectable implant. It is FDA-approved for increasing pain-free light exposure in adults with erythropoietic protoporphyria (EPP). Unlike MT-2, afamelanotide does not significantly activate MC4R and therefore does not produce erections or the broader neurological side-effect profile associated with MT-2.

References

All content is for research and educational use only and is not medical advice. Products are sold for laboratory research only and are not for human consumption.