Library / Skin and hair

Melanotan II

Also known as MT-II, MT2

Failed trials

Synthetic cyclic analogue of alpha melanocyte stimulating hormone that darkens skin and affects sexual arousal. Early human studies did not lead to approval; case reports describe serious adverse effects.

Not an approved medicine. Melanotan II is not an approved medicine for this use in Australia or the United States. This page summarises published research for information only. It is not a recommendation to use Melanotan II, and VialOwl does not sell or supply it.

Background

Melanotan II is a synthetic, ring shaped copy of part of alpha melanocyte stimulating hormone. It was developed at the University of Arizona in the late 1980s and 1990s while researching sunless tanning as a way to reduce skin cancer, and the first small human study was published in 1996. The approved sexual desire drug bremelanotide was later derived from it.

How it is thought to work

It switches on several melanocortin receptors at once. Activating MC1R in pigment cells darkens the skin, while activating MC3R and MC4R in the brain affects appetite, sexual arousal and erections.

What is claimed, and the evidence

Claim	Evidence	Notes
Skin tanning without sun exposure	Small human studies	A 1996 pilot phase I study in 3 men showed increased pigmentation; never approved.
Erections and sexual desire in men with erectile dysfunction	Small human studies	Placebo controlled crossover studies in 20 men found erections in 17; severe nausea in about 13 per cent at the dose tested. Not developed further for this use.
Protection against skin cancer or sunburn	No published evidence	Not shown in humans; case reports instead describe melanoma arising in users.
Appetite suppression and weight loss	No published evidence	Suggested by the receptor biology and user reports; no human trials.

Side effects

Effect	How often	Notes
Nausea	Common	Reported at most dose levels in early studies; severe in about 13 per cent at 0.025 mg/kg in the ED studies.
Yawning and stretching	Common	Frequently reported in human studies.
Spontaneous erections	Common	Occurred for hours after dosing in early studies.
Facial flushing, tiredness, somnolence	Common	Reported in early human studies and user reports.
New or darkening moles and freckles	Common	Widely reported; the pigmenting effect is not selective.
Melanoma Serious	Case reports	Multiple case reports of melanoma, including in young users combining it with sunbeds, and one of oral mucosal melanoma after nasal spray use.
Priapism (prolonged painful erection) Serious	Case reports	Case reports, including one with loss of erectile function at follow up.
Rhabdomyolysis, kidney injury and sympathomimetic toxicity Serious	Case reports	Case report of muscle breakdown and kidney dysfunction after an internet product was injected; a case of kidney infarction also reported.
Posterior reversible encephalopathy syndrome (brain swelling) Serious	Case reports	Case reports cited by FDA.

Warnings

Case reports link Melanotan II to melanoma and to new or changing moles; any changing mole needs medical review.
Serious case reports also include priapism, kidney injury, rhabdomyolysis and brain swelling (PRES).
Prescription only (Schedule 4) in Australia and not approved as a tanning agent; the TGA found seized nasal sprays labelled 30 mg contained between 22 and 54 mg.
Unapproved products are not assessed by the TGA for quality, safety or efficacy and may be contaminated, non-sterile, underdosed, overdosed or contain a different substance altogether.

Regulatory status

Australia: Not included on the ARTG (unapproved). Schedule 4 in the Poisons Standard.
United States: Not FDA approved. Nomination withdrawn and removed from 503A Category 2 in April 2026; FDA previously cited serious adverse events including melanoma and posterior reversible encephalopathy syndrome.

Sources

Also in Skin and hair

From the VialOwl library, reviewed 26 September 2026. For education and general information. It is not medical advice and not a recommendation to use Melanotan II.