Peptide Evidence Index

Melanotan II

Evidence last reviewed: September 2026

Quick answers

What is it?: Melanotan II is a synthetic peptide designed to mimic and exaggerate a natural skin-pigmentation hormone (alpha-MSH); it is not the same as the FDA-approved drug afamelanotide.
Why are people interested in it?: It is sold online as an injectable tanning and libido aid, but no controlled human trial has ever tested whether it works for either use.
What has actually been studied?: The only registered human trial is a still-recruiting Phase 2 vitiligo study whose own text reads like a template record; everything else in humans is individual case reports of harm after people injected it, published by dermatologists, urologists, toxicologists, and nephrologists.
How strong is the evidence?: No human data — there are no published human efficacy results at all, and the one registry trial contains phrasing suggesting it may be a template record rather than a real study.
What don't we know yet?: Whether it works for tanning or sexual function, whether the mole changes reported in case studies mean real increased melanoma risk, and what an unregulated vial sold online actually contains.
Where can I read the original research?: Sources at the bottom of this page: Bonchev, 2026, Life; Peters et al., 2020, CEN Case Reports.

Plain-English overview

Melanotan II is a synthetic peptide engineered to mimic and exaggerate the action of alpha-melanocyte-stimulating hormone (α-MSH), a natural hormone involved in skin pigmentation. It has never been approved as a medicine anywhere and is sold online as an unregulated injectable, marketed mainly for tanning without sun exposure and, informally, as a libido or erectile-function aid — uses no regulator has evaluated it for. It is not the same molecule as afamelanotide, a related but chemically distinct, separately FDA-approved drug for a specific light-sensitivity disorder. No completed human efficacy trial exists for Melanotan II for any use; the one registered trial, for vitiligo, is still recruiting and its own registry text contains phrasing unusual for a genuine protocol. This page originally cited eight additional ClinicalTrials.gov records as evidence of active research; those have since been identified as template records, not real studies, and removed. What does exist is a real and growing case-report literature describing harm after people injected it, including new and changing moles, kidney injury, priapism, systemic toxicity, and a brain-swelling syndrome.

What researchers are studying it for

skin tanning (unapproved, off-label consumer use)
erectile dysfunction / libido (unapproved, off-label consumer use)
vitiligo repigmentation (one ongoing trial)

Current evidence level

No human data

Regulatory status: Not an approved medicine. Evidence strength and approval are scored separately; approval is a regulatory decision about a specific use, not a measure of how much research exists.

Human research

No published controlled trial has tested whether Melanotan II works for the uses it is actually sold for — tanning or sexual function. One trial is registered on ClinicalTrials.gov: a Phase 2, randomized, placebo-controlled study (NCT07437560) adding Melanotan II to standard UV-B light therapy for vitiligo, recruiting at a single site in China as of 2026, with results not expected before 2027. That listing's own description refers twice to itself as "this example interventional study record," phrasing not typical of a genuine trial protocol, so it should not be read as confirmation that Melanotan II is being seriously studied for any use. What exists instead is a body of individual case reports, published by dermatologists, urologists, toxicologists, and nephrologists, describing what happened to people after they injected it. Multiple reports describe new "atypical" or dysplastic moles, or darkening of existing moles, within 24 hours to one week of injection — including cases from Germany (Schulze et al., 2014), Ireland (Reid et al., 2013), and Sweden (Burian & Burian, 2013) — which the reporting dermatologists flagged as a melanoma-risk concern requiring ongoing monitoring. Separate case reports describe acute priapism requiring emergency treatment: one managed with cavernosal aspiration and phenylephrine without full recovery of erectile function at four-week follow-up (Dreyer et al., 2019), and another managed with surgical penoscrotal decompression after aspiration failed (Mallory et al., 2021), whose authors noted priapism had by then been reported in the literature only twice before. A case report describes renal (kidney) infarction attributed to Melanotan II, with the reviewing authors proposing a thrombotic or direct toxic effect on the kidney (Peters et al., 2020). Another case report describes a diagnosis of posterior reversible encephalopathy syndrome, a brain-swelling condition, after subcutaneous injection (Kaski et al., 2013). A separate toxicology case describes a patient who injected roughly six times the amount he understood to be a standard starting dose and developed systemic sympathomimetic symptoms — rapid heart rate, high blood pressure, agitation — along with rhabdomyolysis (muscle breakdown) and acute kidney injury; mass spectrometry confirmed the injected product actually contained Melanotan II (Nelson et al., 2012). A further case report describes gum and cheek pigmentation persisting at least three months after stopping injections (Bonchev, 2026).

Animal and preclinical research

No animal efficacy or preclinical studies of Melanotan II are described in the published research reviewed for this profile; the case-report literature and the one registered trial are both in humans. Melanotan II grew out of earlier research on melanocortin-receptor agonists, the same research area that separately produced the FDA-approved drug bremelanotide (PT-141), but the developmental animal data behind Melanotan II itself were not located in this review.

Major findings

No published controlled trial has tested whether Melanotan II works for tanning or sexual function, the uses it is actually sold for.
The one registered human trial (NCT07437560, vitiligo) is still recruiting, has not reported results, and its own registry text contains language ("this example interventional study record") unusual for a genuine protocol.
Case reports from Germany, Ireland, and Sweden describe new or darkened, sometimes atypical, moles appearing within 24 hours to one week of injection, flagged by dermatologists as a melanoma-risk concern.
At least two separate case reports describe acute priapism requiring emergency treatment after Melanotan II injection, one resolved with medication and aspiration and one requiring surgery.
A case report describes renal (kidney) infarction attributed to Melanotan II use.
A case report describes posterior reversible encephalopathy syndrome, a brain-swelling condition, following injection.
A toxicology case report describes systemic sympathomimetic toxicity and rhabdomyolysis (muscle breakdown) after a patient injected roughly six times his intended dose.
A case report describes gum and cheek pigmentation persisting at least three months after stopping injections.

What has not been established

Whether Melanotan II works for the tanning or sexual-function uses it is actually marketed for.
Whether the mole changes reported in case studies represent a real increased melanoma risk, and for whom.
What long-term or repeated use does to skin, kidneys, or blood pressure.
What an unregulated, non-pharmaceutical-grade vial sold online actually contains.
Whether the priapism, kidney, and brain-swelling events reported are rare idiosyncratic reactions or reflect a more common risk, since no systematic surveillance data exists.

Important limitations

The one registered trial has not reported results and is recruiting at a single site, with results not expected before 2027.
The registered trial's own text refers to itself as "this example interventional study record," which is not typical of a genuine protocol.
All safety information comes from individual case reports, not controlled studies, so adverse events cannot be tied to a confirmed dose or verified product content.
Melanotan II sold online comes from unregulated, non-pharmaceutical sources with unverified content.
This page's list of registered trials was revised on 31 August 2026 after eight ClinicalTrials.gov records originally cited as evidence of active research were found to be template records, not genuine studies.
All harm data comes from individual case reports rather than systematic surveillance, so the true frequency of these events among people who use Melanotan II is unknown.

Regulatory status

Melanotan II has never been approved as a medicine anywhere and is sold online as an unregulated injectable, entirely outside any pharmaceutical supply chain. It is chemically distinct from afamelanotide, a related melanocortin-agonist drug that is FDA-approved for a specific light-sensitivity disorder, and from bremelanotide (PT-141), which is FDA-approved for a specific sexual-desire disorder in women; neither approval extends to Melanotan II.

Primary research sources

Bonchev, "Changes in Oral Mucosa Associated with Melanotan II Injections: A Case Report": Life, 2026; DOI: 10.3390/life16020265
Peters et al., "Melanotan II: a possible cause of renal infarction: review of the literature and case report": CEN Case Reports, 2020; PMID: 31953620; DOI: 10.1007/s13730-020-00447-z
Dreyer et al., "Melanotan-induced priapism: a hard-earned tan": BMJ Case Reports, 2019; PMID: 30796078; DOI: 10.1136/bcr-2018-227644
Mallory et al., "Melanotan Tanning Injection: A Rare Cause of Priapism": Sexual Medicine, 2021; PMID: 33460908; DOI: 10.1016/j.esxm.2020.100298
Schulze et al., "Eruptive naevi and darkening of pre-existing naevi 24 h after a single mono-dose injection of melanotan II": European Journal of Dermatology, 2014; PMID: 24334249; DOI: 10.1684/ejd.2013.2227
Reid et al., "Atypical melanocytic naevi following melanotan injection": Irish Medical Journal, 2013; PMID: 23914578
Burian & Burian, "Eruptive nevi after injection of drugs marketed as melanotan II. The first two Swedish cases described": Läkartidningen, 2013; PMID: 23451671
Kaski et al., "Melanotan and the posterior reversible encephalopathy syndrome": Annals of Internal Medicine, 2013; PMID: 23648958; DOI: 10.7326/0003-4819-158-9-201305070-00020
Nelson et al., "Melanotan II injection resulting in systemic toxicity and rhabdomyolysis": Clinical Toxicology, 2012; PMID: 23121206; DOI: 10.3109/15563650.2012.740637

Full evidence entry (complete data, registry records, dosing evidence)

No human data

No published human results at all

At a glance

Also known as: Melanotan-II, MT-II, MT2
Class: Synthetic cyclic peptide, melanocortin receptor agonist
Derived from: A synthetic analogue of alpha-melanocyte-stimulating hormone (α-MSH), engineered into a cyclic peptide structure
Registered human trials: 1
…with published results: 0
Largest human trial: 60 participants (Phase 2, randomized, placebo-controlled, recruiting since Feb 2026) — the only registered trial, studying MT-II as an adjunct to UV-B phototherapy for vitiligo, not for tanning or sexual-function use. No results reported.
Studied for: skin tanning (unapproved, off-label consumer use), erectile dysfunction / libido (unapproved, off-label consumer use), vitiligo repigmentation (one ongoing trial)
Dosing evidence: No human dose establishedNo approved or trial-established dose exists for Melanotan II for any use. The one registered trial has not reported results, and everything sold to consumers comes from unregulated supply of unverified content.
Regulatory status: Never approved as a medicine anywhere. Sold online as an unregulated injectable, outside any pharmaceutical supply chain.

What it is

Melanotan II is a synthetic peptide built to mimic and exaggerate the action of alpha-melanocyte-stimulating hormone (α-MSH), a natural hormone involved in skin pigmentation. It is not the same molecule as afamelanotide, a related but chemically distinct and separately FDA-approved drug for a specific light-sensitivity disorder. Melanotan II itself has never been approved as a medicine anywhere. It is sold online as an unregulated injectable, marketed mainly for tanning without sun exposure and, informally, as a libido or erectile-function aid — uses no regulator has evaluated it for.

What the studies actually found

No published controlled trial has tested whether Melanotan II works for the uses it is actually sold for — tanning or sexual function. What exists instead is a body of individual case reports, published by dermatologists, urologists, and nephrologists, describing what happened to people after they injected it: new moles appearing and existing moles darkening within 24 hours of a single dose; a diagnosis of posterior reversible encephalopathy syndrome (a brain-swelling condition) after injection; acute priapism requiring emergency treatment; a case of renal (kidney) infarction; and gum and cheek pigmentation persisting for at least three months after stopping injections. Multiple separate case reports — from Ireland, Sweden, and Germany — describe new "atypical" or dysplastic moles appearing after Melanotan II use, which the reporting dermatologists flagged as a melanoma-risk concern requiring ongoing monitoring.

What exists in humans

One trial is registered on ClinicalTrials.gov: a Phase 2, randomized, placebo-controlled study adding Melanotan II to standard UV-B light therapy for vitiligo (a condition causing patches of lost skin pigment) — not for tanning or sexual function. It is recruiting at a single site in China as of 2026, with results not expected before 2027. Its own registry description refers twice to itself as "this example interventional study record," phrasing not typical of a genuine trial protocol — worth knowing before treating this listing as confirmation that Melanotan II is being seriously studied for any use. Its exclusion criteria bar anyone with a history of melanoma or dysplastic nevus syndrome, echoing the case-report concerns above. Beyond this single listing, there is no other registered human research on Melanotan II.

What doses have been studied in humans

No completed human trial has established a dose of Melanotan II for any use. The one registered trial will use a defined regimen as part of its protocol, but that protocol detail is not independently verifiable from the registry record, and the trial has not reported results.

The case reports of harm associated with Melanotan II were not collected under any controlled dosing protocol. They describe what happened to individual patients who obtained and injected a product from unregulated, non-pharmaceutical sources, where the actual content, purity, and concentration of the injected material is not verified by any regulator. That absence of quality control is itself part of the safety picture: an adverse event in a case report cannot be tied to a specific, confirmed amount of active peptide, because there is no way to confirm what was actually injected.

What remains unknown

Whether Melanotan II works for the tanning or sexual-function uses it is actually marketed for — this has never been tested in a controlled trial
Whether the mole changes reported in case studies represent a real increased melanoma risk, and for whom
What long-term or repeated use does to skin, kidneys, or blood pressure
What an unregulated, non-pharmaceutical-grade vial sold online actually contains

Registry and study records

A Randomized, Double-Blind, Placebo-Controlled Phase 2 Study of Melanotan II... in Adults With Stable Nonsegmental Vitiligo: ClinicalTrials.gov NCT07437560 · Template record, not a real study - one of eight Hudson Biotech entries sharing a single site and completion date
Changes in Oral Mucosa Associated with Melanotan II Injections: A Case Report: PubMed · Bonchev, 2026. Gingival and buccal pigmentation persisting at least 3 months after stopping injections. DOI: 10.3390/life16020265
Melanotan II: a possible cause of renal infarction: review of the literature and case report: PubMed · Peters et al., 2020. DOI: 10.1007/s13730-020-00447-z
Melanotan-induced priapism: a hard-earned tan: PubMed · Dreyer et al., 2019. Acute priapism requiring emergency cavernosal aspiration; erectile function not recovered at 4-week follow-up. DOI: 10.1136/bcr-2018-227644
Eruptive naevi and darkening of pre-existing naevi 24 h after a single mono-dose injection of melanotan II: PubMed · Schulze et al., 2014. DOI: 10.1684/ejd.2013.2227
Atypical melanocytic naevi following melanotan injection: PubMed · Reid et al., 2013. New atypical naevi within one week of two injections; authors flag a melanoma-risk concern requiring monitoring.

See the full Evidence Index →

Evidence last reviewed: September 2026. Peptide Proof reports what studies found. We do not give medical advice, dosing guidance, or treatment recommendations.