Key takeaways:
Melanotan II (MT-2) is a peptide that can be purchased as an injection or nasal spray. MT-2 is not FDA approved to treat any medical conditions.
MT-2 is promoted as a tanning agent and as a way to increase sexual function. It has been linked to melanoma and mole changes.
Compounded MT-2 products aren’t checked by the FDA for safety or quality. Products labeled for “research use only” aren’t made for use in people.
Melanotan II (MT-2) is promoted online as a way to tan without exposure to ultraviolet (UV) light. It’s also marketed as a natural way to increase sexual arousal and libido. But the attention around MT-2 has moved much faster than the research.
Here’s what the research shows about MT-2 and what risks to know before using it.
What is melanotan II (MT-2)?
Melanotan II (MT-2) is a peptide made from seven amino acids. It acts like alpha-melanocyte-stimulating hormone (α-MSH), a natural hormone that helps control skin color.
MT-2 is sold online as a UV-free tanning agent. It’s also promoted as a natural way to increase sexual arousal and libido. It’s available as an injection and nasal spray.
Melanotan I (MT-1) and MT-2 were discovered in the 1980s at the University of Arizona. Scientists were studying peptides that could work as a sunless tanning agent and lower the skin cancer risk from UV light exposure.
What are the potential benefits of melanotan II (MT-2)?
MT-2 is promoted as a tanning agent and a natural way to increase sexual function.
MT-2 activates a receptor called MC1R, which increases the amount of dark pigment in the skin. MT-2 also activates a receptor called MC4R, which affects sexual function.
But even though there are lab studies showing how MT-2 works on human receptors, there’s not much research on how MT-2 works in real people.
A lot of discussion around MT-2 benefits is based on research from related compounds and medications. And while these compounds may share similar properties to MT-2, differences in their structure change how they work in the body.
Here’s what the research shows about the potential benefits of MT-2, and how MT-2 relates to similar FDA-approved medications for some of these benefits.
Tanning
Lab studies show that MT-2 can increase the amount of melanin that skin cells make without UV-light exposure. UV light is usually what triggers melanin production. So, in theory, MT-2 can offer a UV-free way to tan so that you avoid sunburns and skin damage. But while researchers were able to show these effects in the lab, they haven’t shown these effects in large clinical trials.
The only human tanning study of MT-2 included just three people. Participants received 5 weekly doses of MT-2, and all three developed a tan. The tanning was still visible 1 week after the last dose. But the study didn’t look at how long the tan lasted. It also didn’t look at whether MT-2 was safe to use more than once, or whether it had any long-term side effects. These questions are still unanswered.
Skin cancer protection
There’s no evidence that MT-2 protects against skin cancer. Researchers first discovered melanotans while looking for a way to create a tan without UV exposure. But there’s no evidence that a tan from MT-2 lowers your risk for developing sunburn or skin cancer. You still need to use sun protection and sunscreen if you take MT-2.
Sexual function
MT-2’s sexual effects were discovered by accident during early tanning studies.
Small, early studies found that melanotans caused erections in some men with some types of erectile dysfunction (ED). Other research suggested that it may increase sexual arousal and libido in men and women.
It’s not clear how well MT-2 works for ED or low libido for most people. Users often point to results seen from the FDA-approved medication bremelanotide to offer guidance.
It’s true that research on MT-2 led to the development of bremelanotide (Vyleesi), an FDA-approved treatment for low libido in premenopausal women. But bremelanotide and MT-2 are different molecules. That means they will not work the same way in the body. So data on efficacy and safety from bremelanotide studies cannot be applied to MT-2.
What are the side effects of melanotan II (MT-2)?
There isn’t enough research to understand all the short-term and long-term side effects of MT-2. We also don’t know how often they happen.
Several medical reports have raised concerns about serious reactions. Reported side effects and possible risks include:
Moles: Some people have developed new or unusual moles while taking MT-2. And some people taking MT-2 with existing moles have developed changes in mole appearance and color.
Melanoma: Several people have developed melanoma while taking MT-2 nasal sprays and injections. Some melanomas developed from existing moles, while others appeared as new melanomas. These reports don’t prove that MT-2 causes melanoma. But experts urge extra caution, especially in people at higher risk for developing melanoma.
Mouth discoloration: MT-2 may cause dark spots or discoloration inside the mouth or along the gums.
Prolonged erections: MT-2 has been linked to priapism, a painful erection lasting more than 4 hours that requires emergency care.
Severe body-wide reactions: One case report linked MT-2 use with signs of an overactive nervous system, muscle breakdown, and kidney problems.
Nausea and flushing: Nausea and skin flushing are among the most commonly reported side effects.
Tiredness and appetite changes: Some people report fatigue, sleepiness, frequent yawning or stretching, and a lower appetite.
Some additional potential risks can be inferred from how MT-2 products are made and used. Risks of compounded injections and nasal sprays include:
Nasal irritation: Intranasal medications may cause nasal dryness, irritation, or bleeding.
Injection-site reactions: Injections may cause pain, redness, swelling, or irritation where the medication is injected.
Infection: A contaminated product can contain bacteria or fungi. If the MT-2 product is contaminated, injecting it could cause a skin infection or a serious infection in the bloodstream.
Immune reactions: Injected peptides can trigger an immune response, which can sometimes be serious or life-threatening.
Is melanotan II (MT-2) FDA approved?
MT-2 injections and nasal sprays aren’t FDA approved to treat any health condition.
The FDA advisory committee plans to meet before the end of February 2027 to discuss whether to recommend adding MT-2 to the 503A bulks list. This list identifies substances that traditional compounding pharmacies may use under certain conditions.
If MT-2 is added to the 503A bulks list, it may be easier for people to access MT-2 nasal sprays and injections. But it doesn’t mean they’re FDA approved.
Compounded MT-2 products will not go through any FDA review to ensure they are effective or safe to use — even if they are added to the 503A bulks list.
Is melanotan II (MT-2) safe?
There isn’t enough information to say whether MT-2 is safe.
But skin cancer experts have asked people not to use MT-2 for tanning. They note that reports of melanoma and mole changes raise serious safety concerns. While these reports don’t prove that MT-2 causes melanoma, the possible risks outweigh the benefits of a tan, especially for people with a higher risk of developing melanoma.
Keep in mind that MT-2 products that are labeled for “research use only” may be available for purchase online and through other retailers. But these products aren’t meant to be used by people. There’s no way to know whether these products are safe for people.
The bottom line
Melanotan II (MT-2) is promoted for tanning and sexual function, but it’s not FDA approved to treat any medical conditions. There’s very little research showing how well it works or whether it’s safe. Reports of melanoma, mole changes, and other serious side effects raise important safety concerns. Avoid products labeled “research use only,” since they aren’t made or tested for use in people.
Why trust our experts?
References
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