Melanotan: What the 2026 Case Reports Show, and What They Cannot Prove

Melanotan I and melanotan II are synthetic versions of alpha-melanocyte-stimulating hormone, the natural hormone that tells pigment cells to make melanin. Melanotan I acts mainly on one receptor, MC1R, found on pigment cells. Melanotan II is non-selective: it acts on several melanocortin receptors, which is why its effects extend beyond the skin, including to sexual function and appetite.

Neither has regulatory approval as a medicine, as the authors of the case reports below note. Both continue to circulate through unregulated online sellers, and both turned up repeatedly in the dermatology literature this year. This article summarises what was reported, and is equally clear about what those reports can and cannot show.

Case 1: five melanomas in situ

A case report in JAAD Case Reports (May 2026) describes a 49-year-old man with fair skin who, over a few weeks in December 2025, used tanning beds and, at the same time, melanotan II and then melanotan I bought from an online vendor. Within about a week he noticed several existing moles darkening rapidly; he described some as having "turned black."

Two to three weeks later, five of his most atypical moles were biopsied. All five showed melanoma in situ, an early, non-invasive form of melanoma confined to the top layer of skin, arising in severely dysplastic (abnormal) moles. All five were surgically removed.

The authors spend as much of the report on limits as on findings:

• He had a high number of atypical moles to begin with, a grandparent with melanoma, past blistering sunburns, years of intermittent tanning-bed use and recent sessions. Tanning-bed use alone is an established melanoma risk factor.
• He was also using testosterone obtained from an unregulated source.
• Given how short the interval was, the melanomas may have existed already and simply become noticeable when the melanotan darkened them.
• What was actually in his products was never independently tested.

Their conclusion: causality cannot be established from a single case. They also note that Australia's Therapeutic Goods Administration has issued public warnings against melanotan tanning products, citing skin cancer among the risks.

Case 2: pigmented gums that outlasted the tan

A case report in Life (February 2026), from a dental faculty in Sofia, Bulgaria, followed a patient who had used melanotan II for 64 days to deepen a tan. Examination found brown pigmentation on the gums of both jaws and irregular patches on the inside of the cheeks.

One month after stopping, the cheek pigmentation had nearly gone. At three months, the gum pigmentation was still visible, though fainter. The author notes there is almost no published data on how long such oral pigmentation takes to resolve.

Case 3: depigmented patches

A report in Clinical and Experimental Dermatology (September 2026) describes the opposite effect: depigmented, lightened patches on the face and neck after melanotan use, in a patient who also had atopic dermatitis and alopecia areata, both immune-related skin conditions. We could read only the citation record for this report, not its full text, so we report its title and nothing further.

The wider picture from the reviews

A systematic review of self-tanning agents in the Journal of Clinical and Aesthetic Dermatology (February 2026), covering 68 studies, states that unregulated melanotan I and II use has caused serious adverse effects, including rhabdomyolysis (a breakdown of muscle tissue that can damage the kidneys), renal infarction (loss of blood supply to part of a kidney) and priapism (a prolonged, painful erection that is a medical emergency).

A narrative review in Sexual Medicine Reviews (September 2026) places melanotan II among agents that remain accessible through unregulated markets, with concerns about product quality, variable content and incompletely characterised adverse effects. It distinguishes melanotan II from bremelanotide, a related melanocortin compound that did go through formal clinical development and regulatory approval for a specific indication.

Why the source of the product matters

An editorial in JAAD International (September 2026) addresses dermatologists seeing patients who obtain unapproved peptides online. Its authors point to impurity-profiling studies that found counterfeit and falsified synthetic peptides with inconsistent content per unit, purities ranging from 5% to 75% for peptides that contain the amino acid cysteine, and toxic elemental impurities including lead and arsenic. They also observe that online listings sometimes pair "research use only" disclaimers with recovery claims, which can give buyers a false sense of legitimacy.

For any reader evaluating research material, the point carries over: a label states what was intended, and only independent analysis shows what is actually present.

What these reports cannot tell us

• Case reports show that something happened, not why. Each case had other plausible causes, and none involved a tested product.
• No rate can be calculated. With no record of how many people use melanotan, there is no way to know how common any of these effects are.
• No controlled human study of melanotan I or II as obtained from unregulated sellers exists in this literature.
• Long-term effects on moles and melanoma risk have not been studied systematically.

What to watch

Dermatology journals have published a steady stream of these reports. The more useful next step would be a systematic case series or registry that records product testing alongside outcomes, so that effects of the compound can be separated from contaminants and from ultraviolet exposure.

Sources

1. Vadner DJ, Smith S. Five primary melanomas in situ in a patient with recent tanning bed use, melanotan exposure, and anabolic hormone use. JAAD Case Reports (2026)
2. Bonchev A. Changes in Oral Mucosa Associated with Melanotan II Injections: A Case Report. Life (2026)
3. Resnick G, et al. Insights into Tanning Biology and Tanning Products. Journal of Clinical and Aesthetic Dermatology (2026)
4. Ume A, Chambers S, Worswick S. Depigmented facial and neck patches following melanotan use in a patient with atopic dermatitis and alopecia areata. Clinical and Experimental Dermatology (2026)
5. Vasylieva V, West A, Karpman E. Peptides in urology and sexual medicine: clinical effectiveness, dosing, indications, and safety: a narrative review. Sexual Medicine Reviews (2026)
6. Zieneldien T, Ma S, Grant-Kels JM. Unapproved peptide therapies and dermatologic care: Ethical boundaries in a gray-market era. JAAD International (2026)

Compounds in this article

Melanotan II