peptide

Melanotan II

A lab-made hormone copy that darkened skin and caused erections in tiny 1990s studies; never approved anywhere, with repeated regulator warnings.

A cyclic, non-selective melanocortin agonist from the University of Arizona that darkened skin and triggered erections in small 1990s studies; never approved anywhere, sold illegally as a tanning product, and the subject of repeated regulator warnings.

Data refreshed 2026-11-01 · Based on 15 published references

At a glance

FDA approved

No.

Potential results

In very small 1990s studies, Melanotan II darkened the skin in 2 of 3 men. It caused erections in 8 of 10 men with erection problems. Nausea was a common side effect.
Single-patient reports describe serious harms after people injected unregulated products. These include muscle breakdown and kidney problems after 6 mg, and an erection lasting 30 hours after 2 mg that needed surgery.

Unverified, online reports only: darkening their skin alongside sun or sunbed exposure.

Dose

Study doses: see the Scientific view
Converter: mg, mL and syringe units

Storage

Powder: fridge (2–8 °C) for the short term, freezer (−20 °C) for the long term; after mixing, fridge for up to 28 days (general guidance, not tested for this compound).

Side effects and warnings

Common side effects in small 1990s studies: nausea, yawning and stretching, and less hunger.
Erections that come on by themselves. Some case reports describe painful erections that would not go away (priapism).
Sleepiness and tiredness at higher doses in the first small safety study.

A summary of the sources on this page, not medical advice.

What else trials studied for sexual health and libido: see the research quiz.

Names

Also called: MT-II, MT-2, Melanotan-2, Melanotan 2

Regulatory (US)

FDA approval: none

503A compounding: unknown
Not on any FDA compounding list; see Regulatory picture.

Molecule

Formula: C50H69N15O9

MW: 1024.2 g/mol

CAS: 121062-08-6

PubChem entry

Sequence: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 (lactam bridge between Asp and Lys)

Origin

Discovered by: Fahad Al-Obeidi, Mac Hadley, Victor Hruby and colleagues, University of Arizona

Year: 1989

What it is

Melanotan II is a lab-made copy of part of a natural hormone called α-MSH. This hormone tells skin cells to make melanin, the dark pigment in skin. Melanotan II is shaped as a closed ring. The ring shape makes it very strong and makes it last a long time.

It does not only act on the skin. It also switches on related targets (receptors) in other places, including the brain. So the early human studies saw more than tanning. People also had erections that came on by themselves. They also had nausea (feeling sick), yawning and less hunger. The researchers had not been looking for these effects.

No medicine with Melanotan II has ever been approved anywhere. US and Australian regulators have acted against people selling it as a tanning shot or nasal spray. The UK regulator says it has taken melanotan products off sale many times. Tests have shown these products often do not contain what the label says.

Melanotan II (Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, C50H69N15O9, 1024.2 g/mol) is a cyclic heptapeptide based on α-MSH(4-10). A lactam bridge between Asp5 and Lys10 constrains the His-D-Phe-Arg-Trp core, and Nle4 with D-Phe7 carries over the stability gains of afamelanotide. Its developers describe it as a non-selective melanocortin receptor agonist (Wessells et al. 2000), and pharmacology studies use it as an MC3R and MC4R agonist. Melanocortin receptor agonism on melanocytes drives eumelanin synthesis via Gs and cAMP; central melanocortin receptor agonism is thought to explain the erectile, appetite-suppressing and yawning–stretching effects.

No published human pharmacokinetic study was found for this article. Bremelanotide, the approved drug in the same family, differs from Melanotan II only by a C-terminal carboxylic acid in place of the amide, and its label reports a subcutaneous half-life of about 2.7 hours; that figure should not be assumed to apply to Melanotan II.

Who made it and when

Melanotan II was made at the University of Arizona in the late 1980s. The team was led by Victor Hruby and Mac Hadley. The same team made Melanotan I. They wanted a stronger way to tan without the sun.

In 1996, a tiny safety study tested it in three men. Two of them got a tan. The men also had erections, which the study was not looking for. In 1998, a second study tested it in ten men with erection problems. This side effect became the more promising lead. A company called Palatin Technologies later made bremelanotide, an almost identical drug. It became the approved medicine Vyleesi. Melanotan II itself was never fully developed as a medicine.

Al-Obeidi, Hadley, Hruby and colleagues described cyclic lactam α-MSH analogues designed with molecular-dynamics modelling in J Med Chem in 1989. Dorr et al. (Life Sci 1996) reported a single-blind, alternating-day, placebo-controlled pilot in three healthy men at 0.01 to 0.03 mg/kg subcutaneously, noting increased pigmentation in two of the three men, intermittent spontaneous erections for 1–5 hours after dosing depending on the dose, mild nausea and, at 0.03 mg/kg, grade II somnolence and fatigue in one man. Wessells et al. (J Urol 1998) ran a double-blind crossover in 10 men with psychogenic erectile dysfunction at 0.025 mg/kg.

Palatin Technologies developed bremelanotide (PT-141), which differs from Melanotan II only at the C-terminus; early Palatin studies used an intranasal formulation (Diamond et al. 2004) before the programme moved to subcutaneous injection. No company is known to be developing Melanotan II itself for approval.

What the data say

There is very little good human evidence. One study had three men. Another had ten men. Both were in the 1990s. No human trial of Melanotan II was registered on ClinicalTrials.gov when this was checked (1 November 2026). The early studies showed darker skin and erections. Nausea was the most common complaint.

Most of what we know about safety comes from case reports. These are reports by doctors about single patients. The patients had bought unregulated products. Doctors saw moles that suddenly got darker or more common. They saw a small number of melanomas (a serious skin cancer). They also saw painful erections that would not go away. Some people had PRES, a brain-swelling condition. Some had muscle breakdown. Case reports cannot prove the drug caused these problems. No one knew what was really in the products. No study has checked whether Melanotan II protects against skin cancer.

Controlled data: n=3 (Dorr 1996) and n=10 (Wessells 1998; erections in 8 of 10, mean tip rigidity above 80% for 38.0 vs 3.0 minutes, p=0.0045). Wessells et al. also reported a study in men with organic erectile dysfunction (Urology 2000). No registered human trial of melanotan II was found on ClinicalTrials.gov as of 2026-11-01.

Case literature: Habbema et al. (Int J Dermatol 2017) reviewed reports of eruptive and changing naevi with unregulated melanotan use and four melanomas arising from existing moles during or shortly after use, noting that conclusive evidence of causation is lacking. Further reports include posterior reversible encephalopathy syndrome (Kaski et al., Ann Intern Med 2013), priapism (Devlin 2013; Dreyer 2019; Mallory 2021), systemic toxicity with rhabdomyolysis (Nelson 2012) and, in 2026, five primary melanomas in situ in one patient who also used tanning beds and anabolic hormones (Vadner and Smith, JAAD Case Rep 2026;73:111-114, PMID 42328529). Dickson et al. (Cureus 2025;17:e98297, PMID 41487785) report a 65-year-old woman whose abdominal “Melanotan” injection sites (product not specified) ulcerated and were diagnosed as pyoderma gangrenosum, healing on prednisolone and topical steroid; the authors describe it as the first reported melanotan-induced case. Ume et al. (Clin Exp Dermatol 2026;51:1971-1974, PMID 42212476) describe vitiligo-like depigmentation of the neck, jaw and cheeks after about 1.5 months of daily self-injection of an unverified melanotan product, with partial repigmentation after stopping. Sidhu et al. (Int J Dermatol 2026;65:1343-1344, PMID 41559011) describe unregulated melanotan use promoted via social media, and Moiz et al. (Mo Med 2026;123:337-343, PMID 42757290) list melanotan II among unapproved “biohacking” injectables, citing contamination, dosing and carcinogenesis risks. FDA cited melanoma, PRES, sympathomimetic toxidrome and priapism when it placed Melanotan II in Category 2.

Regulatory picture

Here are three separate facts.

Approval: The FDA has not approved any product with Melanotan II. No other major regulator has either.

Pharmacy mixing (compounding): In 2023, the FDA put Melanotan II in “Category 2”. This is its list of substances that may be seriously unsafe when pharmacies mix them. By April 2026, the FDA said whoever put it forward had withdrawn it from that list. That does not make it allowed. It is still not on the list of ingredients pharmacies may use.

Enforcement: In 2007, the FDA warned an American seller. The owner was later found guilty. The UK regulator (MHRA) says it has taken melanotan products off sale many times for more than 10 years. In August 2026, Australia’s regulator (TGA) reported fines for illegal supply. Its lab also found nasal sprays with the wrong amount of drug.

Approval: none. No IND-stage programme with a US sponsor could be verified.

Compounding: Melanotan II was placed in Category 2 of the interim 503A policy on 2023-09-29. FDA’s page updated 2026-04-22 lists it among substances “previously in category 2 of the interim policies” that “were withdrawn by the nominators”. It is not a component of an approved drug, has no USP monograph and is not on the 503A bulks list (21 CFR 216.23), and it was not reviewed at the July 2026 Pharmacy Compounding Advisory Committee meeting. This article records compounding status as unknown.

Enforcement: FDA issued a warning letter on 2007-08-30 to a US company selling Melanotan II; its president pleaded guilty in 2015 to conspiracy under 18 U.S.C. 371 and FDA proposed permanent debarment on 2016-08-05. In Australia Melanotan II is a prescription-only medicine with no product on the ARTG; the TGA’s advisory of 2026-08-17 reported 27 infringement notices, paid in May 2026. The UK’s MHRA stated in 2021 that melanotan tanning products are not automatically medicines under UK law but that it had removed such products from sale for over 10 years. In sport it is not named on WADA’s list and falls under S0, non-approved substances.

Dose

Doses reported in trials and studies

How dosing worked in the studies

In the 1996 Pilot Phase 1 study, 3 healthy men got shots under the skin. There was no comparison group. They got shots on alternating weekdays, with salt water (saline) on the other days, for 2 weeks. The dose started at 0.01 mg/kg. It went up in 0.005 mg/kg steps to target doses of 0.025 or 0.03 mg/kg. Two studies by Wessells (1998 and 2000) each had 10 men with erection problems. Neither the men nor the researchers knew who got what (double-blind). Each man had both 0.025 mg/kg and a dummy treatment (placebo), at different times. In the 2000 study, Melanotan II and placebo were each given twice, under the skin.

Doses used in the studies are in the Scientific view.

Study doses are not personal dosing instructions. Reading doses safely: how concentration and syringe markings work.

Doses reported in studies, exactly as the cited trial reported them. They are not personal dosing instructions. Population, route and schedule matter more than the number.

Trial	Phase	Status	Population	Dose	Result
Pilot Phase 1 study of Melanotan II Dorr 1996	1	Completed (published 1996)	3 healthy men, University of Arizona	Subcutaneous injection starting at 0.01 mg/kg, given on alternating weekdays with saline for 2 weeks, escalated in 0.005 mg/kg steps to 0.025 or 0.03 mg/kg	Increased pigmentation of face, upper body and buttocks in 2 of 3 men; spontaneous erections 1–5 hours after dosing; mild nausea; grade II somnolence and fatigue at 0.03 mg/kg in one man (Dorr et al., Life Sci 1996)
Melanotan II in psychogenic erectile dysfunction Wessells 1998	N/A	Completed (published 1998)	10 men with erectile dysfunction of no known organic cause	0.025 mg/kg by injection versus vehicle placebo, double-blind crossover; the abstract does not state the route	Erections in 8 of 10 men; mean time with tip rigidity above 80% was 38.0 vs 3.0 minutes on placebo (p=0.0045); nausea, yawning, stretching and reduced appetite (Wessells et al., J Urol 1998)

Doses in other published studies

Published studies not listed in the trials table above: smaller or unregistered human studies first, then animal and cell studies. Doses are shown exactly as each study reported them. Animal studies report weight-based doses, absolute amounts or concentrations; none translates directly to people, and none is converted here.

Subjects	Design	Dose	Finding	Source
Humans: 10 men with erectile dysfunction and organic risk factors	Double-blind, placebo-controlled crossover study; RigiScan penile monitoring over 6 hours and a sexual-desire questionnaire	Melanotan II 0.025 mg/kg by subcutaneous injection; Melanotan II and vehicle were each administered twice	Erections were subjectively reported after 12 of 19 Melanotan II injections versus 1 of 21 placebo doses (mean duration of tip rigidity above 80% 45.3 vs 1.9 minutes, P = 0.047), sexual desire was significantly higher than after placebo, and 4 of 19 injections were associated with severe nausea.	Wessells H et al., Urology, 2000
Humans: 1 man aged 39 (case report)	Case report of a self-administered, internet-purchased product whose identity was confirmed as Melanotan II by mass spectrometry; urine drug screen was also positive for opiates	6 mg injected subcutaneously, single injection	He developed sympathomimetic toxicity (heart rate up to 146 bpm, mydriasis, sweating, tremor), rhabdomyolysis with CPK peaking at 17,773 IU/L and renal dysfunction, and was discharged from intensive care after 3 days.	Nelson ME et al., Clinical Toxicology, 2012
Humans: 1 man aged 55 (case report)	Case report of self-administered Melanotan II; the report states there was no concomitant use of other drugs	2 mg by subcutaneous injection to the abdomen, single injection; the report states he had used Melanotan II each year before summer for over 6 years, injecting once before bedtime, and had tolerated the same dose in those years	He presented with ischaemic priapism of 30 hours' duration that did not resolve with intracavernosal phenylephrine and irrigation and was treated with surgical penoscrotal decompression; at 15-week follow-up he reported new-onset erectile dysfunction with corporal fibrosis on examination.	Mallory CW et al., Sexual Medicine, 2021
Rats: adult rats, conscious (telemetric intracavernosal pressure sensor) and anaesthetised	Saline-controlled dose comparison measuring intracavernosal pressure	0.1, 0.3 and 1 mg/kg intravenous, single injection, or saline i.v.	In conscious rats 1 mg/kg significantly increased overall erectile activity compared with saline; in anaesthetised rats the increase showed a similar pattern but was not statistically significant.	Giuliano F et al., European Urology, 2005
Mice: C57BL/6J mice with high-fat diet-induced obesity	Acute and chronic dosing study with controls, plus a separate central-administration arm	100 microg intraperitoneal four times daily (q.i.d.), with outcomes reported after 8 days of treatment; central administration 10 nmol/day for 4 days	Peripheral MTII markedly suppressed feeding during the first 4 days, with food intake returning to control levels at day 5, while body weight plateaued below control and leptin and insulin levels were suppressed after 8 days.	Pierroz DD et al., Diabetes, 2002
Mice: C57BL/6 mice with established B16-F10 melanoma (n = 6 per group); also B16-F10 melanoma cells in vitro	Preclinical melanoma model with topical application versus untreated controls, plus cell-culture migration, invasion and colony-formation assays	Topical, once daily, described by the authors as 0.1 μg per tumor, for 10 days per the methods (the figure legend states once daily for 14 days); in vitro 10 nM for migration assays and 0.1 nM to 1 μM for invasion assays	Topical MTII attenuated growth of established melanomas in mice and, in cells, inhibited migration, invasion and colony formation without a marked effect on proliferation; the authors note that only one topical dose was tested. This experiment does not establish cancer prevention or safety in humans.	Wu JC et al., International Journal of Molecular Sciences, 2020

Mixing examples reported by protocol websites

Examples for the freeze-dried powder, as reported by protocol websites, not taken from studies. The water amount only sets the concentration (how much is in each mL); it does not change how much of the compound is in the vial. Each concentration assumes the vial really holds its labelled amount and the final liquid volume equals the water added.

Vial	Water added	Concentration
10 mg	1.0 mL	10 mg/mL
10 mg	2.0 mL	5 mg/mL
10 mg	5.0 mL	2 mg/mL

Clean the rubber tops of both vials with an alcohol swab.
Add the water slowly, letting it run down the inside wall of the vial rather than onto the powder.
Swirl or roll gently until the powder dissolves; protocol sites advise against shaking.
The liquid should be clear. If it is cloudy or has specks in it, do not use it. Clear liquid does not show that the product is pure, the right strength or sterile.
Write the date and the concentration on the vial, and keep it in the fridge (2–8 °C). No safe storage time after mixing has been established for these products.

Products sold as "research peptides" have not gone through FDA review for safety, effectiveness or quality. Bacteriostatic water does not sterilize a contaminated powder. It contains benzyl alcohol, and its label says it is not for use in newborns. To work out a volume from your own numbers, use the converter.

Doses described in clinical or compounding practice

From FDA labels and documents, other regulators, published reviews and professional references, as each source states them. Unless a source says otherwise, these describe practice or proposals, not results tested in trials. Reading doses safely: how concentration and syringe markings work.

In this case report, a 49-year-old man was injecting Melanotan II that he got from an online vendor to tan. He "reported daily injections with dose escalation over approximately 1 week from 250 mcg to 500 mcg to 1000 mcg, with each dose level maintained for approximately 3 days". He then moved to melanotan I "using a similar dosing and titration schedule" while also using a tanning bed. The authors call melanotan I and II unregulated and say causality cannot be established. (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 Rep 2026;73:111-114 (PMID 42328529), Peer-reviewed)
This case report describes a 42-year-old man who injected himself with Melanotan II bought from an online retailer specialising in research peptides. He injected it "subcutaneously in the lower abdomen at a dose of 400 micrograms every other day over a 64-day period, for a total of 32 injections and a cumulative dose of 12.8 mg", alongside 5 sunbed sessions. A dental exam found brown pigmentation of the gums and both inner cheeks, and the author notes that Melanotan II remains unregulated. (Bonchev A. Changes in Oral Mucosa Associated with Melanotan II Injections: A Case Report. Life (Basel) 2026 Feb 3;16 (PMID 41752902), Peer-reviewed)
This systematic review reports a case of oral mucosal malignant melanoma in a young woman "following one month of melanotan II nasal spray use, administered as two puffs into each nostril twice daily". The case was first reported by Yassin Alsabbagh et al., Int J Oral Maxillofac Surg 2025;54:806-808 (PMID 40210573). The review gives no milligram amount per spray, and it notes that some studies show no link between melanotan and melanoma. (Resnick G, Khajeh-Afzaly M, Yousefian F, Raza A, Issa NT. Insights into Tanning Biology and Tanning Products. J Clin Aesthet Dermatol, 2026 (systematic review), Peer-reviewed)
This case report states that a 16-year-old girl "had been injecting subcutaneous 0.5 mg of Melanotan 2 daily over two months" while attending a solarium two to three times weekly. She had bought the Melanotan 2 on the internet. (Sivyer GW. Changes of melanocytic lesions induced by Melanotan injections and sun bed use in a teenage patient with FAMMM syndrome. Dermatology Practical & Conceptual, 2012, Peer-reviewed)

Doses reported in online communities (untested)

Unverified, and not a recommendation. These are amounts people describe in online forums such as Reddit, collected so researchers can see how practice differs from the evidence. These forum accounts are not clinical evidence, even where they overlap studied doses. Products sold online as "research peptides" are not FDA approved, and their identity, purity and strength are not verified; they can be mislabeled, contaminated or wrongly dosed.

What people report

In the threads reviewed, people described subcutaneous injections of roughly 100 to 500 mcg per dose, with a few describing 1 mg or 2 mg, taken from daily to once a week; two described nasal sprays. Posters disagreed about amounts and whether the drug protects the skin. Side effects raised in more than one thread were nausea, flushing, diarrhoea, spontaneous erections, new freckles and moles, and darkening of existing moles. Single reports included flu-like aches, lasting darker hair and freckles, blood-pressure spikes, palpitations, chest pain and kidney pain.

How this compares with the studies

The published human studies gave weight-based injections (0.01 to 0.03 mg/kg) in small placebo-controlled studies, while threads describe fixed amounts of unregulated products whose content was not verified, so exposure cannot be compared. Case reports at 2 mg and 6 mg do not establish a safe threshold. Melanotan II is not FDA approved, and community reports do not establish safe tanning use or protection against UV damage.

Open questions a study would need to answer

Is the number, size or change of moles in people using unregulated Melanotan II related to the amount used, the length of use or concurrent UV exposure, as assessed by prospective dermatological follow-up?
What are the human pharmacokinetics of Melanotan II after subcutaneous and intranasal administration, and how closely does the content of purchased or seized products match their labels?
Are heart rate, blood pressure, kidney function or muscle enzymes measurably altered in people who use Melanotan II repeatedly, given published case reports of rhabdomyolysis (Nelson 2012) and renal infarction (Peters 2020)?

Threads consulted, checked 2026-09-26: MT2 Before & After (r/moreplatesmoredates) · Overdose melanotan 2 (r/Peptides) · Considering MT2 (r/Peptides) · Melanotan II, medication resistant hypertension, kidney pain, heart palpitation (r/Peptides) · MT-2 for brown / darker individuals (r/Peptides) · MT2 Flu-Like Feeling...is MT1 better? (r/Peptides) · Anyone pale here that used Melanotan ii? (r/tanning) · Anyone here tried melanotan2 and still use it ? What u think of it? (r/moreplatesmoredates)

Enforcement history

2007-08-30 · FDA warning letter: FDA told a US company marketing Melanotan II as an injectable tanning product that it was an unapproved new drug. Shipments continued; the company's president pleaded guilty to conspiracy in 2015 and FDA proposed his permanent debarment in August 2016. (source)
2023-09-29 · 503A Category 2 placement: FDA placed Melanotan II in Category 2 of the interim 503A bulk drug substances policy, citing immunogenicity risk from aggregation or peptide impurities and published case reports of melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxidrome and priapism. (source)
2026-04 · Withdrawn from Category 2: FDA's safety-risk page (updated 2026-04-22) lists Melanotan II among substances previously in Category 2 that were withdrawn by their nominators. It is not on the 503A bulks list and was not on the July 2026 advisory committee agenda. (source)
2026-08-17 · TGA infringement notices and testing: A TGA safety advisory published on 17 August 2026 reported 27 infringement notices, totalling A$101,412, issued to an individual in New South Wales for alleged unlawful supply of Melanotan II and paid in May 2026. TGA laboratory testing of five seized nasal spray bottles labelled 30 mg found an estimated 22 to 54 mg of Melanotan II per bottle. (source)

Side effects and warnings

Common side effects in small 1990s studies: nausea, yawning and stretching, and less hunger.
Erections that come on by themselves. Some case reports describe painful erections that would not go away (priapism).
Sleepiness and tiredness at higher doses in the first small safety study.
Darker skin and moles all over. Case reports describe new or changing moles.
A small number of case reports describe melanoma (a serious skin cancer) growing from existing moles. It has not been shown that the drug caused this.
Single case reports describe PRES (a brain-swelling condition), poisoning with a racing heart, and muscle breakdown.
A 2025 report describes a 65-year-old woman whose belly injection sites turned into open sores. Doctors diagnosed pyoderma gangrenosum, a rare skin condition, and it healed with steroid treatment. A 2026 report describes pale patches (like vitiligo) on the face and neck of a man who injected a melanotan product daily for about 6 weeks.

Full lists are in the Scientific view.

Reported side effects

Nausea, yawning and stretching, reduced appetite (small 1990s studies)
Spontaneous erections; priapism in published case reports
Somnolence and fatigue at higher doses (Phase 1 pilot)
Generalised darkening of skin and moles; new or changing naevi in published case reports
Melanoma arising from existing moles in a small number of case reports; a causal link has not been established
Posterior reversible encephalopathy syndrome, sympathomimetic toxicity and rhabdomyolysis in isolated case reports
Pyoderma gangrenosum at abdominal injection sites (single 2025 case report, product not specified); vitiligo-like depigmentation after daily injection of a melanotan product (single 2026 case report)

Interactions

Not catalogued yet.

Contraindications

Not catalogued yet.

Storage

No approved product exists, so there is no label storage data. Storage figures published by online sellers are supplier claims, not verified data.

General storage guidance commonly given for freeze-dried research peptides and powders, not stability data for this substance. Storage conditions and usable life depend on the specific product and formulation; follow its documented instructions.

Condition	Temperature
Temporary (transportation), in powdered form	15 °C – 25 °C / 59 °F – 77 °F
Short term (1–3 years)	2 °C – 8 °C / 36 °F – 46 °F
After reconstitution (28 days)	2 °C – 8 °C / 36 °F – 46 °F
Long term (2–5 years)	−20 °C / −4 °F or below

Product characteristics

Form: No approved formulation exists; the research literature used a synthetic lyophilised peptide dissolved for injection

Appearance: White to off-white powder (as described in the research literature)

Compound information

Synthetic cyclic heptapeptide amide with a lactam bridge. No manufacturer safety data sheet from a regulated drug maker was found. TGA testing has shown that illegally supplied products can contain far more or less than the labelled amount.

Molecule, patents, enforcement history, full trial tables and compound details are in the Scientific view.

Common questions

What is Melanotan II?

Is Melanotan II FDA approved?

Not FDA approved for any use.

What have studies found?

In very small 1990s studies, Melanotan II darkened the skin in 2 of 3 men. It caused erections in 8 of 10 men with erection problems. Nausea was a common side effect.
Single-patient reports describe serious harms after people injected unregulated products. These include muscle breakdown and kidney problems after 6 mg, and an erection lasting 30 hours after 2 mg that needed surgery.

How was it dosed in studies?

What are the side effects and warnings?

Common side effects in small 1990s studies: nausea, yawning and stretching, and less hunger.
Erections that come on by themselves. Some case reports describe painful erections that would not go away (priapism).
Sleepiness and tiredness at higher doses in the first small safety study.
Darker skin and moles all over. Case reports describe new or changing moles.
A small number of case reports describe melanoma (a serious skin cancer) growing from existing moles. It has not been shown that the drug caused this.
Single case reports describe PRES (a brain-swelling condition), poisoning with a racing heart, and muscle breakdown.
A 2025 report describes a 65-year-old woman whose belly injection sites turned into open sores. Doctors diagnosed pyoderma gangrenosum, a rare skin condition, and it healed with steroid treatment. A 2026 report describes pale patches (like vitiligo) on the face and neck of a man who injected a melanotan product daily for about 6 weeks.

Is it legal to buy as a "research peptide"?

Products sold as "research use only" or "not for human consumption" are not approved for use in people. That label does not make them legal to sell for human use, and their contents are not checked by any regulator.

References

This page summarises the published sources below. PeptideBasics101 does no original research. Trial doses and results are reported as the cited study or label reported them. Sources can themselves be wrong or superseded; if you find a statement here that does not match its source, please tell us through our corrections process. Sources were last checked on 2026-11-01.

Based on 15 published references

FDA: certain bulk drug substances for use in compounding that may present significant safety risks (Category 2 and withdrawn substances) (fda.gov)
Dorr RT et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sci 1996 (pubmed.ncbi.nlm.nih.gov)
MHRA: FOI 21/1237, Yellow Card reports and regulatory action on melanotan II products (December 2021) (assets.publishing.service.gov.uk)
Al-Obeidi F et al. Potent and prolonged acting cyclic lactam analogues of α-melanotropin. J Med Chem 1989 (pubmed.ncbi.nlm.nih.gov)
FDA: notice of opportunity for hearing on proposed debarment (Melanotan II marketing case), August 2016 (fda.gov)
TGA: Melanotan II tanning peptide products found to be inconsistently dosed (tga.gov.au)
Habbema L et al. Risks of unregulated use of α-MSH analogues: a review. Int J Dermatol 2017 (pubmed.ncbi.nlm.nih.gov)
PubChem: Melanotan II (CID 92432) (pubchem.ncbi.nlm.nih.gov)
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 Rep 2026;73:111-114 (pubmed.ncbi.nlm.nih.gov)
Bonchev A. Changes in oral mucosa associated with Melanotan II injections: a case report. Life (Basel) 2026;16 (pubmed.ncbi.nlm.nih.gov)
Yassin Alsabbagh A et al. Int J Oral Maxillofac Surg 2025;54:806-808 (case report: oral mucosal melanoma after melanotan II nasal spray) (pubmed.ncbi.nlm.nih.gov)
Dickson D et al. Cureus 2025;17:e98297 (case report: pyoderma gangrenosum at melanotan injection sites) (pubmed.ncbi.nlm.nih.gov)
Ume A, Chambers S, Worswick S. Clin Exp Dermatol 2026;51:1971-1974 (case report: vitiligo-like depigmentation after self-injecting a melanotan product) (pubmed.ncbi.nlm.nih.gov)
Sidhu AS et al. Unregulated Melanotan Use Promoted via Social Media (letter). Int J Dermatol 2026;65:1343-1344 (pubmed.ncbi.nlm.nih.gov)
Moiz A et al. Mo Med 2026;123:337-343 (review of unapproved "biohacking" injectables, naming melanotan II) (pubmed.ncbi.nlm.nih.gov)

Clinical trial entries in the table above link to their ClinicalTrials.gov registry records. Spotted an error? See corrections.