# Melanotan II side effects: what regulators and studies report Updated 2026-10-16. The TGA names headache, nausea, vomiting, loss of appetite and facial redness as the most common side effects of melanotans. It says the most concerning one is the risk of serious skin cancers. For Melanotan II, it adds reports of more moles and freckles, kidney dysfunction and swelling of the brain. These are a regulator's summaries of reports. They are not rates measured in a trial. | | | | --- | --- | | Common effects named by the TGA | Headache, nausea, vomiting, loss of appetite, facial redness (TGA, 24 January 2025) | | Most concerning risk named by the TGA | Serious skin cancers (TGA, 24 January 2025) | | Reports named for Melanotan II by the TGA | Increased moles and freckles, kidney dysfunction, swelling of the brain | | Case-report categories named by the FDA | Melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxidrome, priapism (page checked on 16 October 2026) | | Severe nausea in the 20-man report | 12.9 percent of subjects at one tested level (Wessells et al., 2000) | | Rates in a large trial | Not established in the opened sources; small studies do not establish population rates | Your body treats any new signalling molecule as news. Pigment cells, the gut, the brain and blood vessels all carry receptors in the melanocortin family, so a peptide that reaches several of them can produce effects in several places. That is the thread running through [the Melanotan II hub](/learn/melanotan-2). This page sorts what has been reported by source and by weight. It starts with the effects regulators call common. Then it covers the serious reports they name, and the few numbers from human trials. It ends with what is not known, because for Melanotan II the gaps are wide. ## What are the common side effects of Melanotan II? The TGA lists headache, nausea, vomiting, loss of appetite and facial redness as the most common side effects of melanotans. Small human studies also reported nausea. The 1996 pilot study included 3 healthy men. Mild nausea appeared at most levels tested, and it needed no anti-sickness medicine. One of the two men at the highest level had grade II somnolence and fatigue. That means moderate sleepiness and tiredness on the World Health Organization scale. In a 2000 report covering 20 men, nausea and yawning were frequently reported. None of these sources says how often each effect happens in the wider population. Notice what is missing: a rate. The TGA gives no percentages. The small studies give some counts and percentages, but those cannot show how often an effect happens across a whole population. A figure from 3 or 20 people can swing widely from one group to the next. [The study findings page](/learn/melanotan-2/melanotan-2-study-findings) shows each trial's size and design. ![Diagram: a plain human outline with four marked areas labelled Headache, Facial redness, Nausea and Appetite loss.](/assets/content/edu-common-reported-effects-body-map.png) The TGA names headache, nausea, vomiting, loss of appetite and facial redness as the most common side effects of melanotans (TGA blog, 24 January 2025). It gives no rates for them. ## How often did nausea occur in Melanotan II trials? Nausea was frequent in the 20-man crossover research. In a crossover study, each person receives both the real treatment and a placebo, a dummy treatment, at different times. At one tested level, 12.9 percent of the men had severe nausea. That is the only percentage for a Melanotan II side effect from a controlled trial in the sources searched. The 1996 pilot study reported mild nausea but gave no count. Neither study was built to give a safe-use rate for the public. Both enrolled men only, so they say nothing direct about women. Do not borrow numbers from a related molecule, such as the one covered in [what Melanotan II is](/learn/melanotan-2/what-is-melanotan-2). PT-141 is a different peptide with an approved product and a label, and its figures belong to it alone. In its phase 3 trials, nausea, flushing and headache were the events seen in at least 10 percent of people and more often than with placebo. Those figures do not describe Melanotan II, so the two sets of numbers stay apart. ## What serious problems have been reported with Melanotan II? The FDA says published case reports describe serious problems with Melanotan II. They include melanoma, a dangerous skin cancer. They include posterior reversible encephalopathy syndrome, a condition with swelling in the brain. They include sympathomimetic toxidrome, where the body's fight-or-flight system goes into overdrive. And they include priapism, a long, painful erection. The TGA reports kidney dysfunction and swelling of the brain with Melanotan II. A 2017 review found four case reports of melanomas growing from existing moles during or shortly after melanotan use. The review says conclusive evidence linking the two is lacking. A case report is one person's story, written up by a doctor. It can raise an alarm, but it cannot give a rate or prove cause. The published studies discussed here are small and do not settle long-term safety. This page cites the FDA sentence and the 2017 review. It does not analyse the individual case reports. ## Does Melanotan II change moles? Changes to moles have been reported. For Melanotan II, the TGA lists increased moles and freckles. A 2017 review of published papers says case reports of unregulated melanotan use are linked with skin complications. The main ones are changes in existing moles and newly emerging dysplastic nevi, which are moles with irregular cells. The review adds that the link is not proven. A link in case reports is not the same as proof of cause. The TGA also says that skin darkened this way is not protected from ultraviolet light the way a suitable sunscreen protects it. A person who has used a melanotan product and notices a mole changing shape, colour or size is the kind of person the TGA tells to speak to a health professional. A vitiligo trial entry on ClinicalTrials.gov lists a history of melanoma or dysplastic nevus syndrome as a reason to exclude people. Vitiligo is a condition that causes pale patches of skin. The entry's summary calls it an example record, so that rule does not prove an active study or establish a risk ([ClinicalTrials.gov NCT07437560](https://clinicaltrials.gov/study/NCT07437560)). ## Do contamination and product quality add to the risk? Product quality adds a layer of risk that nobody has measured. The FDA says compounded drugs containing Melanotan II may pose a risk of immunogenicity for certain routes into the body. Immunogenicity means the immune system reacts against the peptide. The FDA links this to aggregation, where peptide molecules clump together, or to impurities related to the peptide. The TGA confirmed Melanotan II in five seized nasal spray bottles of one brand. The estimated amount in the highest bottle was more than twice that in the lowest. The TGA says inconsistent strength like this raises the chance of harmful effects. The TGA adds that products bought online may be fake. They may contain hidden or harmful ingredients, and they may not contain what the label says. The TGA's advice to consumers is to stop using tanning products containing Melanotan II. It asks them to take any remaining product to a pharmacy for safe disposal, and to talk to a health care practitioner about concerns. It also asks that suspected side effects be reported to the TGA. [Is Melanotan II legal in Australia?](/learn/melanotan-2/is-melanotan-2-legal-in-australia) records the schedule and approval status. ## What is not known about Melanotan II safety? The sources searched found no large trial, no long-term follow-up, no regulator label and no half-life for Melanotan II. So these sources do not show how often side effects happen across a population. The reports discussed here covered 3 men and 20 men. They do not show safety in other groups of people. Case reports and regulator warnings show what has been reported, not how often it happens. A reader who has had a reaction should speak to a health professional. The TGA's advisory page invites people to report reactions to the TGA. Writing this honestly means resisting a tidy list with percentages. These sources do not establish population rates. What exists is a short record: small trials, a regulator's list of reports, and a laboratory finding that bottles of one brand varied in content. [How Melanotan II works](/learn/melanotan-2/how-melanotan-2-works) gives the receptor background that makes the range of reports easier to follow. ## Comparison Side-effect statements for Melanotan II, grouped by source type. A blank cell means the source gives no count or rate. This is a record of what each source says, not a ranking of risks. | Source type | Source | What it names | Rate or count given | | --- | --- | --- | --- | | Regulator, Australia | TGA blog, 24 January 2025 | Headache, nausea, vomiting, loss of appetite, facial redness; skin cancer risk; moles and freckles, kidney dysfunction, swelling of the brain | None | | Regulator, United States | FDA, page checked on 16 October 2026 | Immunogenicity risk; case reports of melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxidrome, priapism | None | | Pilot study | Dorr et al., 1996 (3 men) | Mild nausea; grade II somnolence and fatigue in one of two men at the highest level; stretching and yawning | Counts for 3 men only | | Controlled trial | Wessells et al., 2000 (20 men) | Nausea, yawning | 12.9 percent severe nausea at one tested level | | Literature review | Habbema et al., 2017 | Changes in moles; four melanoma case reports | None; causal link not proven | ## Frequently asked questions ### Are Melanotan II side effects the same as PT-141 side effects? No. The two peptides are different molecules, and their records are separate. PT-141, also called bremelanotide, has a US label and trial figures of its own. The TGA reports no approved Melanotan II product in Australia. ### Can Melanotan II cause kidney problems? The TGA lists kidney dysfunction among the reports about Melanotan II. Its blog gives no count, and the sources searched do not establish cause. ### What does the TGA advise if someone has used a product? The TGA advises people who have recently used unapproved melanotan tanning products to stop and to speak to a health professional. ### Is a Melanotan II tan safe from sun damage? The TGA says skin that has been darkened artificially will not be protected from ultraviolet light the way a suitable sunscreen protects it. ## Citations - Dorr RT, Lines R, Levine N, et al.. Life Sciences. 1996;58(20):1777-1784. DOI: 10.1016/0024-3205(96)00160-9 - Wessells H, Levine N, Hadley ME, Dorr R, et al.. International Journal of Impotence Research. 2000;12(Suppl 4):S74-S79. DOI: 10.1038/sj.ijir.3900582 - Habbema L, Halk AB, Neumann M, Bergman W. International Journal of Dermatology. 2017;56(10):975-980. DOI: 10.1111/ijd.13585 - Kingsberg SA, Clayton AH, Portman D, et al.. Obstetrics and Gynecology. 2019;134(5):899-908. DOI: 10.1097/AOG.0000000000003500 --- Canonical page: https://www.formlaboratories.com/learn/melanotan-2/melanotan-2-side-effects Form Laboratories - Perth-based research-use-only peptide supplier, shipping Australia-wide. - Site guide for agents: https://www.formlaboratories.com/llms.txt - Sitemap: https://www.formlaboratories.com/sitemap.xml - Full catalogue: https://www.formlaboratories.com/shop - Contact: hello@formlaboratories.com All materials are supplied for laboratory research use only - not for human or veterinary use, and nothing on this site is medical advice.