Melanotan II: research, side effects and dosage in studies
In short
Melanotan II is a synthetic peptide that mimics the hormone alpha-MSH; it has no marketing authorisation in the EU [7]regulator. There are only three small human studies, from 1996-2000 [1, 2]B [3]A.
- People use melanotan without supervision mainly for tanning [4]. The human studies included 23 men in total [1, 2]B [3]A.
- In the smallest study, skin pigment increased in two of three men [1]B. In two small placebo-controlled studies it produced erections [2]B [3]A.
- Case reports link use to mole changes, new moles and four melanomas. Cause and effect has not been shown, but several health authorities have warned against it [4].
- Melanotan II is listed in Annex 1 A of Fimea's medicines list, so in Finland it is treated like a prescription-only medicine [9]regulator. Fimea warns against injectable peptides bought online [8]regulator.
What is melanotan II?
Melanotan II (MT-II) is a ring-shaped peptide of seven amino acids. It is a modified form of the body's own alpha-MSH (alpha-melanocyte-stimulating hormone), which regulates skin pigment [1]B. The first human study described it as a superpotent pigment-stimulating substance [1]B.
According to a dermatology review, people use melanotans without medical supervision mainly for tanning, and this use has increased. The substances are commonly known as melanotan I and II [4].
Melanotan II is not the same substance as afamelanotide. Afamelanotide is another alpha-MSH-like substance that holds an EU marketing authorisation for a rare light-sensitivity disease [6]regulator. Basics: What are peptides?. All substances: Peptides A-Z.
Evidence at a glance
Each cell gives the kind of study and its source. The letter is the evidence level, not the result.
| Claimed effect | Humans | Animals | Cells |
|---|---|---|---|
| Tanning (skin pigment) | 3 healthy men, pigment increased in 2 [1]B | - | - |
| Erection, psychogenic erectile dysfunction | 10 men, placebo comparison; erection in 8 of 10 [2]B | - | - |
| Erection, organic risk factors | 10 men, placebo comparison; erection after 12 of 19 injections, after 1 of 21 with placebo [3]A | - | - |
| Moles and melanoma | Case reports of mole changes and four melanomas; cause and effect not shown [4] | - | - |
| Safety | Nausea, yawning and fatigue in small studies [1, 2]B [3]A; priapism in a case report [5]B | - | - |
"-" = no such study is known.
What is melanotan II studied for?
Melanotan II has been studied in humans for two things, and neither is an approved use [7]regulator.
- Skin tanning: one phase 1 pilot study in three healthy men [1]B.
- Erectile dysfunction: two small placebo-controlled studies with ten men each [2]B [3]A.
Claims online. Use for tanning rests on this one study of three men [1]B. According to the review, unsupervised use raises questions about preparation, administration and dosage [4].
How does melanotan II work?
Melanotan II mimics the hormone alpha-MSH, which regulates skin pigment [1]B. In the pilot study it increased skin pigment in two of three men [1]B.
The first study also observed a stretching and yawning complex that seemed to go with spontaneous erections [1]B. This observation led to the erection studies [2]B [3]A.
According to a review, melanotan II is a non-selective melanocortin receptor agonist: it acts on several melanocortin receptors, not only the one that controls skin pigment [10]. That is why it has several effects in humans: in studies skin pigment increased and it caused spontaneous erections [1, 2]B [3]A.
Has melanotan II been studied in humans?
Yes, but very little. Three human studies have been published, all small and from 1996-2000, with 23 men in total. No large or long-term safety studies have been published [1, 2]B [3]A.
Human studies
- Tanning (1996). In a phase 1 pilot study, three healthy men received melanotan II or saline as an injection under the skin on weekdays for two weeks, with melanotan II on every other weekday and saline on the days in between. Two of the three had increased pigmentation of the face, upper body and buttocks, measured by reflectance and by eye one week after dosing [1]B.
- Erections in the same study. Erections occurred on and off for 1 to 5 hours after a dose, depending on the dose [1]B.
- Psychogenic erectile dysfunction (1998). In a placebo-controlled crossover study, ten men had psychogenic erectile dysfunction. With melanotan II, eight of ten developed an erection. Tip rigidity above 80% lasted a mean of 38.0 minutes with melanotan II and 3.0 minutes with placebo [2]B.
- Organic risk factors (2000). In a second similar study, ten men had organic risk factors. Erections were reported after 12 of 19 melanotan II injections and after 1 of 21 placebo doses. Tip rigidity above 80% lasted a mean of 45.3 minutes, versus 1.9 minutes with placebo [3]A.
These are small studies and they say nothing about long-term benefit or safety. The results also do not transfer to a product bought online whose content is unknown [4] [8]regulator.
Who studies melanotan II?
All three human studies come from the same University of Arizona research group, 1996-2000 [1, 2]B [3]A. More recent literature deals mainly with the harms of unsupervised use, such as the dermatology review [4] and a case report of prolonged erection [5]B.
Who wrote this page: the editorial team
This page was written by the Molecular Recovery editorial team. The draft was made with the help of AI, and the claims were checked against the sources (AI policy). The page has not been medically reviewed. How we work: About us.
What are the side effects of melanotan II?
In the small studies of melanotan II the most common harm was nausea. Case reports link unsupervised use to mole changes, melanoma and prolonged erection [1]B [3]A [4] [5]B.
What users report. In the Reddit accounts we compiled (not research), 65 of 109 people (60%) reported some harm, most often: uneven or unwanted darkening (freckles, face, lips) (24, 22%), nausea or vomiting (18, 17%) and flushing (12, 11%). People tend to post when something goes wrong, so this share does not tell how common harms are. Almost all accounts (112 of 114) came from the users' own forum r/Melanotan2, where a tan is the goal. 7 (6%) described mole changes; the accounts cannot tell how often such changes are dangerous. The harms in detail: Melanotan II user experiences.
Harms in studies
- In the pilot study nausea occurred at most dose levels, and the highest dose caused somnolence and fatigue in one of two subjects [1]B.
- In the 2000 study, four of 19 injections were followed by severe nausea [3]A.
- Stretching, yawning and decreased appetite were more frequent than with placebo [2]B.
Mole changes and melanoma
According to a dermatology review, a growing number of case reports link unsupervised melanotan use to skin changes. These are particularly changes in existing moles and new, sometimes atypical, moles [4].
Four case reports described melanoma arising from an existing mole during or shortly after use. The review states that conclusive evidence of cause and effect is lacking [4]. A case report cannot prove cause and effect, but it cannot rule it out either.
Prolonged erection (priapism)
A case report described painful, prolonged erection after a melanotan injection. It was treated in the emergency department without surgery, but the patient had not recovered erectile function at four-week follow-up [5]B.
Risks in products
According to Fimea, there is no reliable information on the content, quality and safety of products sold as peptides. In injectables, impurities such as endotoxins can cause serious harm to health [8]regulator. More: Side effects and safety.
Interactions and who lacks data
Interactions with other medicines have not been studied. All dose studies were done in men, so there are no data for women [1, 2]B [3]A. For the same reason there are no data for pregnancy, breastfeeding or children.
What speaks against it and what is unknown
The evidence is old and very small, and one research group did all the studies [1, 2]B [3]A. There are no studies of long-term safety.
Contrary evidence
- In the pilot study pigment increased in only two of three men [1]B.
- Nausea was common, and severe after some injections [1]B [3]A.
- Case reports from unsupervised use concern moles, melanoma and priapism [4] [5]B.
What the evidence does not support
- "Melanotan is a safe way to tan": there are no long-term safety studies, and use has been linked to mole changes and melanomas [4].
- "Melanotan II is the same as approved afamelanotide": it is not. Afamelanotide is authorised, melanotan II is not [6, 7]regulator.
- "Melanotan is well researched": there are three human studies with 23 men in total [1, 2]B [3]A.
- "The vial contains what the label says": according to Fimea, an unauthorised product may contain a different substance from the one on the label [8]regulator.
Melanotan II dosage in studies
Melanotan II has no approved dosage, because it has no marketing authorisation [7]regulator. Below are the doses used in three small human studies. They are not recommendations.
| Study | Who | Dose and route | Duration |
|---|---|---|---|
| Pilot study (1996) | 3 healthy men | 0.01 mg/kg under the skin at first, raised to 0.025-0.03 mg/kg; every other weekday, saline on the days in between | 2 weeks [1]B |
| Psychogenic erectile dysfunction (1998) | 10 men | 0.025 mg/kg by injection, placebo on another occasion | monitored 6 hours after the dose [2]B |
| Organic risk factors (2000) | 10 men | 0.025 mg/kg under the skin, placebo on other occasions | monitored 6 hours after each injection [3]A |
What the numbers do not tell you. The doses were given under supervision at the study site, and in the erection studies each dose was a single dose [2]B [3]A. There are no dose data for women [1, 2]B [3]A. More: melanotan II doses in studies. The calculator only converts units, and its result is not dosing guidance.
Melanotan II vs afamelanotide: what is the difference?
Both are alpha-MSH-like substances, but only afamelanotide has a marketing authorisation [6, 7]regulator.
- Afamelanotide (Scenesse): an EU-authorised medicine for a rare light-sensitivity disease [6]regulator. Afamelanotide is the same molecule as melanotan 1: melanotan 1 or 2.
- Melanotan II: not in the EMA medicines data [7]regulator; only three small human studies [1, 2]B [3]A.
- Online: according to the review, the substances are sold for unsupervised use commonly as melanotan I and II [4].
See also: PT-141 (bremelanotide).
Is melanotan II legal in Finland?
Melanotan II is listed in Annex 1 A of Fimea's medicines list [9]regulator. Annex 1 A substances are controlled as medicines in Finland and are always treated like prescription-only medicines. Melanotan II has no marketing authorisation [7]regulator.
- Medicines list. Melanotan II is listed in Annex 1 A of the Finnish medicines list (230/2025), which lists medicinal substance analogues and prohormones classified as medicines [9]regulator.
- Marketing authorisation. The EMA medicines data file generated on 15 Sep 2026 does not include melanotan II, but it does include afamelanotide (Scenesse) [6, 7]regulator.
- Fimea warning, 29 June 2026. Fimea warned about injectable peptides bought online and sold as "for research use only". According to Fimea, that label means the product is not intended for humans, and medicines should be bought only from legal pharmacies [8]regulator.
- Other authorities. According to the review, several national health authorities have issued warnings about melanotans [4].
- Import. Ordering medicines from outside the EU is covered on Peptides and the law in Finland. Bringing them back from travel: Travelling with peptides.
This is not legal advice. Disclaimer.
Is melanotan II a doping substance?
Probably. The WADA 2026 Prohibited List does not name melanotan II, but class S0 always prohibits pharmacological substances that no other class covers and that have no approval by any government health authority for human therapeutic use. Class S0 substances are prohibited out of competition too [11]regulator. Melanotan II has no marketing authorisation in the EU [7]regulator. Athletes should check with their national anti-doping organisation.
How is a melanotan product assessed?
You cannot be sure what a product contains. According to the review, illegal melanotans raise questions about preparation, administration and dosage [4], and according to Fimea an unauthorised product may contain a different substance from the one on the label [8]regulator.
A seller's own certificate of analysis (COA) does not by itself prove purity or content, and it does not show that the product is safe. More: How to read a COA and check a test result. Handling: Mixing and handling.
FAQ
Is melanotan II an approved medicine?
No. It has no marketing authorisation in the EU. Afamelanotide, from the same family, is a different substance that is authorised [6, 7]regulator.
Does melanotan II tan the skin?
In the pilot study, two of three men had increased pigmentation. The study was very small [1]B.
Can melanotan cause mole changes or melanoma?
This is not known for certain. Case reports describe changes in moles and new moles, and four describe melanoma arising from an existing mole. Cause and effect has not been shown [4].
What side effects of melanotan II have been reported?
In studies: nausea, fatigue, yawning and spontaneous erections [1, 2]B [3]A. A case report also described priapism, after which erectile function had not recovered within four weeks [5]B.
Is melanotan legal in Finland?
It is listed in Annex 1 A of Fimea's medicines list, so in Finland it is treated like a prescription-only medicine, and it has no marketing authorisation [7, 9]regulator. Fimea warns against injectable peptides bought online [8]regulator. This is not legal advice.
Is melanotan II a doping substance?
Probably. The Prohibited List does not name it, but class S0 always prohibits substances with no approval by any government health authority for human therapeutic use [11]regulator. Check with your national anti-doping organisation.
What doses were used in studies?
The erection studies used 0.025 mg/kg as a single dose [2]B [3]A. This is not dosing guidance: dosage in studies.
Is melanotan II the same as melanotan 2?
Yes. Melanotan II, melanotan 2 and MT-II are names for the same substance [1]B [4].
What do users themselves report about Melanotan II?
In the Reddit accounts of 109 people we compiled (not research), 62 (57%) reported some benefit and 65 (60%) some harm. The accounts are self-selected and prove neither that it works nor that it is safe: Melanotan II user experiences.
Read the research yourself: sources
Every source opens the original publication or the regulator's page. The level shows what the source itself reports.
- Dorr RT, et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sci. 1996;58:1777-1784. PMID 8637402 B
- Wessells H, et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study. J Urol. 1998;160:389-393. PMID 9679884 B
- 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. 2000;56:641-646. PMID 11018622 A
- Habbema L, et al. Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review. Int J Dermatol. 2017;56:975-980. PMID 28266027 (review)
- Dreyer BA, et al. Melanotan-induced priapism: a hard-earned tan. BMJ Case Rep. 2019;12(2). PMID 30796078 B
- European Medicines Agency. Scenesse (afamelanotide): EPAR summary and authorisation details. EMA regulator
- European Medicines Agency. Medicine data (human medicines, data set of 15 Sep 2026): melanotan II not listed. EMA regulator
- Fimea. Fimea varoittaa: älä käytä verkosta ostettuja pistettäviä peptidejä / Fimea warns: do not use injectable peptides purchased online. 29 Jun 2026. Fimea regulator
- Finland. Lääkeluettelo (Fimea medicines list), 230/2025, annex 1 A. Finlex regulator
- Peters B, Hadimeri H, Wahlberg R, Afghahi H. Melanotan II: a possible cause of renal infarction: review of the literature and case report. CEN Case Rep. 2020;9(2):159-161. PMID 31953620 (review)
- WADA. World Anti-Doping Code International Standard: Prohibited List 2026, class S0 Non-Approved Substances. wada-ama.org (PDF) regulator
Research sources checked 9-13 Oct 2026. Regulator and registry sources checked 15 Sep to 13 Oct 2026.
Evidence levels: A = randomised human trial or meta-analysis · B = observational human study or case series · C = animal study · D = cell or laboratory study · E = not peer-reviewed · regulator = a regulator's assessment or decision, not research evidence. The marker official means official product information (summary of product characteristics or label); it is not research evidence. For a review, the level shows what kind of research the statement rests on. No level: statements that something has not been studied, reviews' interpretations, named hypotheses and the general rules in our certificate-of-analysis guide.
Content is general information about research, not medical advice. If you have symptoms, contact a healthcare professional.