Summary
Melanotan II is a ring-shaped, lab-made version of alpha-MSH, the hormone that tells skin to make pigment, developed at the University of Arizona in the 1980s; it darkens skin, causes erections, and suppresses appetite by activating several melanocortin receptors at once. It was never approved anywhere; the only human trials are two double-blind crossover studies (each man got both drug and placebo without knowing which) of 10 men each from 1998 and 2000 showing erections after a single injection under the skin, with frequent nausea and yawning, and its selective metabolite (breakdown product) became the approved drug bremelanotide instead. FDA placed it on the 503A Category 2 compounding list (ingredients flagged for significant safety risks) citing case reports of melanoma (skin cancer), posterior reversible encephalopathy syndrome (brain swelling), sympathomimetic toxidrome (an overstimulation reaction), and priapism (a painful erection that will not go away), and the nomination was withdrawn in April 2026, so it has no lawful route to patients.
What is Melanotan II?
Melanotan II is a synthetic cyclic heptapeptide analog of alpha-melanocyte stimulating hormone; nonselective melanocortin receptor agonist (MC1R, MC3R, MC4R, MC5R). It is also known as MT-II, MT2, Melanotan 2, Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, Barbie peg (slang), Tanning peptide, Melanotan, MT2 peptide, MT-2, Melanotan 2 peptide.
How does it work?
Melanotan II is a superpotent, nonselective agonist at melanocortin receptors. MC1R activation on melanocytes increases eumelanin synthesis and produces tanning without UV exposure, along with darkening of existing moles. MC4R and MC3R activation in the hypothalamus produces penile erection, increased sexual desire, reduced appetite, and stretching and yawning. Off target and receptor mediated effects on blood pressure and heart rate are documented in its metabolite bremelanotide.
| Cluster | Sexual health and reproductive |
|---|---|
| Routes | Subcutaneous injection (trials and as sold); Nasal spray (as sold; no studies); Products labeled research use only are not lawful for human use |
| Conditions studied | Sexual dysfunction; Erectile dysfunction |
| Record | v3, draft, verified Sep 22, 2026 |
Melanotan II benefits: what the evidence shows
Two small double-blind, placebo-controlled crossover trials from the developing group in the 1990s. In 10 men with psychogenic erectile dysfunction, 0.025 mg/kg subcutaneously produced clinically apparent erections in 8 of 10, with mean tip rigidity above 80% lasting 38 minutes versus 3 minutes for placebo. In 10 men with organic erectile dysfunction, erections followed 12 of 19 injections versus 1 of 21 placebo doses, sexual desire increased, and severe nausea followed 4 of 19 injections. The only tanning data come from a 1996 pilot phase I study in 3 men, 2 of whom developed measurably darker skin, and the published human safety literature since then consists of case reports of harm.
| Evidence type | Indexed studies | Participants (human) |
|---|---|---|
| Human randomized trials | 2 | 20 |
| Human observational studies | 1 | 3 |
| Animal studies | 0 | n/a |
| All indexed studies | 6 | 23 |
Human evidence
Dorr 1996: single-blind, placebo-controlled pilot phase I study in 3 healthy men; 2 had increased pigmentation of the face, upper body, and buttock 1 week after a short course of injections, with mild nausea, yawning and stretching, and spontaneous erections. Wessells 1998: double-blind, placebo-controlled crossover, 10 men with psychogenic erectile dysfunction, Melanotan II 0.025 mg/kg subcutaneously; erections in 8 of 10, mean duration of tip rigidity above 80% of 38.0 minutes versus 3.0 minutes with placebo (p = 0.0045); nausea, stretching and yawning, and decreased appetite more frequent than placebo. Wessells 2000: same design in 10 men with organic risk factors; erections after 12 of 19 injections versus 1 of 21 placebo doses, mean rigidity score 6.9 of 10 in responders, higher sexual desire, and severe nausea after 4 of 19 injections. Case reports since: melanoma in a 20 year old woman who combined it with sunbed tanning (2014), eruptive naevi and darkening of existing naevi within 24 hours of a single injection (2014), priapism requiring treatment (2019), renal infarction (2020), and oral mucosal pigment changes (2026). FDA also cites reports of melanoma, posterior reversible encephalopathy syndrome, and sympathomimetic toxidrome.
Animal evidence
Melanotan II induces skin darkening in frogs, mice, and guinea pigs and penile erection and grooming behaviors in rats through central melanocortin receptors. Rodent studies also show reduced food intake and body weight through MC4R, work that later informed setmelanotide and bremelanotide development.
Key studies
| Study | Design and population | Outcome | Grade |
|---|---|---|---|
| Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study1998 PMID 9679884 | Double-blind, placebo-controlled crossover trial with RigiScan monitoring, single 0.025 mg/kg subcutaneous dosen = 10 Men with erectile dysfunction of no known organic cause | Erections in 8 of 10 men; tip rigidity above 80% for 38.0 minutes versus 3.0 minutes with placebo (p = 0.0045); nausea, stretching, yawning, and decreased appetite more frequent | Evidence: Human RCT evidence |
| Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction2000 PMID 11018622 | Double-blind, placebo-controlled crossover trial, two doses each of Melanotan II 0.025 mg/kg and vehiclen = 10 Men with erectile dysfunction and organic risk factors | Erections after 12 of 19 injections versus 1 of 21 placebo doses; tip rigidity above 80% for 45.3 versus 1.9 minutes; higher sexual desire; severe nausea after 4 of 19 injections | Evidence: Human RCT evidence |
| Eruptive naevi and darkening of pre-existing naevi 24 h after a single mono-dose injection of melanotan II2014 PMID 24334249 | Case reportOne adult user | Eruptive new naevi and darkening of existing naevi within 24 hours of a single injection | Evidence: Anecdotal evidence only |
| Melanotan-induced priapism: a hard-earned tan2019 PMID 30796078 | Case reportOne adult user | Priapism after melanotan use requiring medical intervention | Evidence: Anecdotal evidence only |
| Melanotan II: a possible cause of renal infarction: review of the literature and case report2020 PMID 31953620 | Case report with literature reviewOne adult user | Renal infarction temporally associated with Melanotan II use | Evidence: Anecdotal evidence only |
| Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study1996 PMID 8637402 | Single-blind, placebo-controlled pilot phase I study (alternating injection days)n = 3 Healthy men | Increased pigmentation of the face, upper body, and buttock in 2 of 3 subjects 1 week after dosing ended; mild nausea, yawning and stretching, and spontaneous erections | Evidence: Human observational evidence |
Conditions studied
| Condition | Grade | Note |
|---|---|---|
| Sexual dysfunction | Evidence: Human RCT evidence | Small randomized placebo-controlled crossover studies of erectile response in the 1990s (short-term, surrogate endpoints); not approved; sold illegally as a tanning injectable. |
| Erectile dysfunction | Evidence: Human RCT evidence | Produced erections in 8 of 10 men in a small placebo controlled crossover study, with frequent nausea; case reports of priapism; not approved. |
Is Melanotan II legal in the United States?
FDA and compounding status
Melanotan II was placed on the FDA 503A Category 2 list (substances that may present significant safety risks) with FDA citing immunogenicity risk, peptide impurities, and published case reports of melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxidrome, and priapism. As of the FDA page current to April 22, 2026, its nomination has been withdrawn, so it no longer sits in Category 2, but it is not on the 503A bulks list, was not among the peptides the Pharmacy Compounding Advisory Committee took up in July 2026, and is not a component of any approved drug. A 503A pharmacy therefore has no basis to compound it. It is not approved as a drug in any country.
WADA status
WADA prohibited. Athletes subject to anti-doping testing should treat this as prohibited at all times unless the current prohibited list says otherwise.
Regulatory timeline
- FDA
FDA lists BPC-157 and 16 other peptides as withdrawn from 503A Category 2
FDA's Category 2 page, revised in April 2026 and current as of April 22, 2026, moved BPC-157, AOD-9604, CJC-1295, dihexa, DSIP, epitalon, injectable GHK-Cu, ipamorelin, KPV, LL-37, melanotan II, MOTS-c, PEG-MGF, selank, semax, thymosin alpha-1, and thymosin beta-4 fragment (TB-500) to a list of bulk drug substances nominated but withdrawn by their nominators. A withdrawn substance is no longer in 503A Category 2, but withdrawal is not an approval and does not place a substance on the 503A bulks list; a 503A pharmacy still needs a listing before it may compound it. Ipamorelin acetate remains in 503B Category 2. Seven of the withdrawn peptides (BPC-157, KPV, TB-500, MOTS-c, semax, epitalon, and DSIP) were taken to the Pharmacy Compounding Advisory Committee in July 2026.
- FDA
FDA places a batch of nominated peptides in 503A Category 2
In September 2023 FDA updated its 503A bulk drug substances category lists to place a group of nominated peptides in Category 2, which means FDA identified significant safety risks and the substances may not be used in 503A compounding while the evaluation continues. Kisspeptin-10 and ibutamoren (MK-677) were added on September 29, 2023 and remain in Category 2 on the FDA page current as of April 22, 2026. BPC-157, CJC-1295, ipamorelin, AOD-9604, dihexa, DSIP, epitalon, KPV, MOTS-c, selank, semax, melanotan II, LL-37, thymosin alpha-1, and thymosin beta-4 fragment (TB-500) were also placed in Category 2 under the 503A interim policy; that same page now lists them as nominated but withdrawn (see the April 2026 event). Hexarelin, PNC-27, and 5-amino-1MQ have never appeared on the FDA category lists.
What published studies of Melanotan II used
Ranges below are reported from published studies and labeling only. PeptideAgent does not recommend doses or protocols.
The two human trials used a single subcutaneous dose of 0.025 mg/kg given on separate occasions. No repeat dose, tanning, or dose finding study has been published; the loading and maintenance schedules described by sellers have no literature basis.
Routes reported
| # | Route |
|---|---|
| 1 | Subcutaneous injection (trials and as sold) |
| 2 | Nasal spray (as sold; no studies) |
| 3 | Products labeled research use only are not lawful for human use |
Melanotan II side effects
Side effects
| # | Reported side effect |
|---|---|
| 1 | Nausea, sometimes severe (4 of 19 injections in the 2000 trial) |
| 2 | Stretching and yawning, flushing, decreased appetite |
| 3 | Spontaneous erections and priapism (case report requiring intervention) |
| 4 | Darkening of existing moles and eruptive new naevi, sometimes within 24 hours of one dose |
| 5 | Melanoma reported in association with use (causality not established; FDA cites published case reports) |
| 6 | Posterior reversible encephalopathy syndrome and sympathomimetic toxidrome (FDA cited case reports) |
| 7 | Renal infarction (case report) |
| 8 | Rhabdomyolysis and infections from unsterile injection products reported in the case literature |
Interactions
| # | Interaction |
|---|---|
| 1 | No formal interaction studies exist |
| 2 | Additive blood pressure and heart rate effects with sympathomimetics are plausible based on its metabolite bremelanotide |
| 3 | PDE5 inhibitors: combined use has not been studied with Melanotan II and priapism risk may increase |
Contraindications
| # | Contraindication |
|---|---|
| 1 | Personal or family history of melanoma or many atypical moles |
| 2 | Cardiovascular disease or uncontrolled hypertension (based on bremelanotide data) |
| 3 | Pregnancy and breastfeeding (no data) |
| 4 | Competitive athletes subject to WADA testing (prohibited at all times under S0) |
How do people access Melanotan II legally?
Typical cost: Not available through licensed channels. Gray market vials are sold online for tanning, but those products are not lawful for human use and have been found unsterile or mislabeled.
Verified access options
Step 1
Not legally available for human use in the United States.
Step 2
Not an FDA approved drug and not compoundable under 503A or 503B.
Step 3
Products sold online as tanning injections or nasal sprays are not lawful for human use and are not verified for purity.
Access paths are verified against public regulatory records and prescriber licensing. We never list unlicensed vendors.
Compare Melanotan II
What's actually offered, and what that means for you
Licensed compounding pharmacies, clinics, and telehealth prescribers openly offer many unapproved peptides, and prescribers write prescriptions for them. That does not make melanotan II lawful. Melanotan II is not FDA approved and not on the 503A bulks list, so a pharmacy has no lawful basis to compound it. [6] [12]
Enforcement is uneven. FDA mostly acts through warning letters to compounders and online sellers, Category 2 safety listings, and import alerts that let it detain shipments, rather than stopping every pharmacy. State pharmacy boards oversee pharmacies day to day, and their rules differ. [6] [7] [13] [14] [15]
What changes for you
- No FDA review of the product: FDA does not check a compounded drug's safety, effectiveness, or quality before it is sold. [7]
- Identity, purity, sterility, and dose accuracy can vary from batch to batch. [6]
- Insurance rarely covers it, so you usually pay cash.
- For tested athletes, melanotan II is prohibited at all times on the WADA list, whatever the source. [8]
What to check
These checks lower some risks, but they do not make an unlawfully compounded product lawful or safe. Check for:
- A 503A pharmacy licensed in your state (your state board of pharmacy publishes license lookups). [7]
- A real evaluation by a licensed prescriber, not just an online form.
- A certificate of analysis for the specific batch.
Nothing is approved for tanning. Afamelanotide (Scenesse), the approved form of melanotan I, is approved only for erythropoietic protoporphyria, and bremelanotide (Vyleesi) is approved for low sexual desire in premenopausal women. See Afamelanotide (melanotan I), Bremelanotide (PT-141).
Frequently asked questions
What is the tanning peptide called?
The injection sold as the tanning peptide is usually melanotan II, also called MT2 or MT-II. It is a synthetic copy of alpha-MSH, the hormone that tells skin cells to make melanin (skin pigment). Its relative melanotan I (afamelanotide) is FDA approved only as an implant for erythropoietic protoporphyria, a rare disease that makes light exposure painful, not for cosmetic tanning. Melanotan II is not approved anywhere and has no lawful source in the United States. [6] [9] [11]
Is Melanotan II legal in the United States?
There is no lawful route to obtain it for human use. It is not an approved drug in any country, FDA listed it in Category 2 of the 503A compounding program because of safety case reports, and the nomination was withdrawn in April 2026 rather than advanced. It is sold online as a tanning injection, and those sales are unlawful drug marketing. Possession itself is not a criminal matter. [6] [7]
Does Melanotan II work for erectile dysfunction?
In two very small crossover trials, yes: a single injection produced erections in 8 of 10 men with psychogenic erectile dysfunction and after 12 of 19 injections in men with organic erectile dysfunction, along with increased sexual desire. The trade-off was nausea, sometimes severe, and yawning. Its selective metabolite, bremelanotide, was developed instead and is the approved product. [1] [2]
Does Melanotan II give you a tan?
Yes. It darkens skin by stimulating melanin production through the MC1R receptor. A 1996 pilot study in 3 men measured darker skin in 2 of them after a short course, and no larger tanning trial has been done. The same mechanism darkens existing moles and can trigger eruptive new naevi within a day of a single dose, which complicates skin cancer surveillance, and FDA cites case reports of melanoma in users. [3] [6] [9]
Does melanotan 2 work without sun?
Partly. In the 1996 pilot study, 2 of 3 men had measurably darker skin on the face, upper body, and buttock a week after dosing ended, including skin that is rarely sun exposed, because the peptide stimulates pigment cells directly. The study was tiny and did not control sun exposure, and users commonly add sun or sunbeds, which adds ultraviolet damage on top. A published melanoma case followed melanotan II combined with sunbed tanning. [9] [10]
How does Melanotan II work?
It is a cyclic, long acting copy of alpha-MSH that switches on several melanocortin receptors at once. The receptor on skin pigment cells drives tanning, while receptors in the brain drive erections, sexual desire, reduced appetite, and the yawning and nausea seen in trials. That lack of selectivity is why a more selective relative, bremelanotide, became the approved drug instead. No human half-life study of melanotan II has been published. [1] [9]
What are the side effects of Melanotan II?
In trials: nausea (severe after 4 of 19 injections), stretching and yawning, flushing, loss of appetite, and spontaneous erections. In case reports: priapism needing emergency treatment, eruptive and darkening moles, melanoma after use with sunbeds, renal infarction, and mouth pigment changes. FDA additionally cites melanoma, posterior reversible encephalopathy syndrome, and sympathomimetic toxidrome. Unsterile gray market vials add infection risk. [2] [4] [5] [6] [10]
How is Melanotan II taken?
The trials gave single subcutaneous injections under medical supervision. Sellers describe loading phases and maintenance injections or nasal sprays for tanning that have never been studied, and no repeat dose safety data exist. PeptideAgent does not give doses for unapproved peptides. [1] [9]
How much does Melanotan II cost?
There is no licensed price because it cannot be lawfully dispensed. Products sold as research chemicals are not lawful for human use and are not verified for identity or purity. [6]
Is Melanotan II banned by WADA?
Yes. Melanotan II has no approval from any government health authority, which places it in section S0 (non-approved substances) of the WADA Prohibited List. It is prohibited at all times. [8]
Melanotan II vs Melanotan I: what is the difference?
Melanotan I (afamelanotide) is a linear analog selective for MC1R, approved by FDA in 2019 as a subcutaneous implant for the rare light sensitivity disease erythropoietic protoporphyria; it tans but does not cause erections or nausea to the same degree. Melanotan II is a cyclic, nonselective analog that hits MC3R and MC4R too, which is why it affects libido and appetite, and it was never approved. Only afamelanotide has a lawful route, and only for its approved indication. [2] [6]
Decisions about starting, stopping, or combining any treatment belong with a licensed clinician who knows your history.
From the blog
- Melanotan 2 before and after: what trials and case reports show
Melanotan 2 before and after photos show a tan. Early trials measured it in a few men; case reports since document new moles, melanoma, priapism and FDA safety concerns.
- Sildenafil vs Viagra: same drug, generic vs brand
Sildenafil is the active ingredient in Viagra. How generic sildenafil compares, why 20 mg tablets are labeled for pulmonary hypertension, the label side effects, and the nitrate contraindication.
- Melanotan 1 before and after: what the afamelanotide trials measured
Melanotan 1 is afamelanotide, approved only as an implant for a rare light sensitivity disease. What the tanning and approval trials measured, what happens to moles, and why tanning use is unapproved.
- Peptides for men, ranked by human evidence
hCG, GLP-1 drugs, teriparatide, and tesamorelin have human trials and a lawful route. PT-141 is off-label for men, and kisspeptin and melanotan II have no lawful path. Ranking, legality, and WADA.
- Peptides for women, ranked by human evidence
GLP-1 drugs, teriparatide, abaloparatide, and Vyleesi (PT-141) have real trials in women. Kisspeptin is research-only and GHK-Cu rests on small skin studies. The ranking and legal status.
Sources
Numbered citations above point to these primary sources. PubMed entries link to the indexed abstract.
- [1]Wessells H et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study. J Urol 1998PubMed 9679884, 1998
- [2]Wessells H et al. Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction. Urology 2000PubMed 11018622, 2000
- [3]Schulze F et al. Eruptive naevi and darkening of pre-existing naevi 24 h after a single mono-dose injection of melanotan II. Eur J Dermatol 2014PubMed 24334249, 2014
- [4]Dreyer BA et al. Melanotan-induced priapism: a hard-earned tan. BMJ Case Rep 2019PubMed 30796078, 2019
- [5]Peters B et al. Melanotan II: a possible cause of renal infarction: review of the literature and case report. CEN Case Rep 2020PubMed 31953620, 2020
- [6]FDA: Certain bulk drug substances for use in compounding that may present significant safety risks (Category 2 list and withdrawn nominations, current as of April 22, 2026)FDA, 2026
- [7]FDA: Compounding and the FDA, questions and answersFDA, 2026
- [8]WADA Prohibited List, section S0 non-approved substancesWADA, 2026
- [9]Dorr RT et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sci 1996PubMed 8637402, 1996
- [10]Hjuler KF, Lorentzen HF. Melanoma associated with the use of melanotan-II. Dermatology 2014PubMed 24355990, 2014
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<a href="https://peptideagent.ai/peptides/melanotan-ii">Melanotan II: evidence, legality, and access</a>, PeptideAgent, updated September 22, 2026.