Melanotan-2 Explained: Main Benefits, Dosages & Use Cases

The below article and information is based on lab research data of Melanotan-2, this is not medical advice in any kind of shape or form.

The sun is the classic “frenemy.” Without it, the Earth would be a cold, lifeless planet — but while this humble G-type main-sequence star is directly responsible for making anything anyone has ever valued possible, it also kills. 

Around 1.5 million people settle into doctors’ offices to hear the scary news that they have skin cancer every year. More than 100,000 of them will eventually succumb to that diagnosis. The cause? In over 90 percent of cases, it’s the sun. More precisely, excessive exposure to its dangerous UV rays. 

Researchers created Melanotan 2 to fix that. Research to make a compound with the ability to trigger pigment building started in the 1980s at the University of Arizona.  Researchers wanted to induce a tan, but without the sun. Without UV exposure. The dream? To give fair-skinned people with a massively elevated risk of skin cancer a shield to keep them safe. And to get people out of the tanning beds that were so popular at the time. 

Melanotan 2 — the synthetic answer to α-MSH — lives a bit of a double life, though. This melanocortin agonist does what the team that discovered it hoped it would. It creates a deep, beautiful, sunless tan. But it also has other effects. Ones the team that made it never saw coming. 

Melanotan 2 reduces appetite; it gives people who don’t seem to be able to stop eating an “out.” Even more strangely, from a research perspective, the peptide reawakens libido and sexual desire. (Researchers found out when study participants came to them with comments like, “You know what? I do have a tan, but I also keep having these erections.”) 

It’s one of the most interesting research peptides around today, and definitely well worth reading more about. Curious? Of course you are! This deep dive should quench your thirst for knowledge. 

A Brief & Interesting History of Melanotan 2 Peptide

You already know the “why” behind Melanotan 2. What about the “how?” 

The team that discovered it — led by pharmacologist Dr Victor Hruby and endocrinologist Dr Mac Hadley — started with the natural peptide alpha-Melanocyte-Stimulating Hormone. It already binds to melanocortin receptors to induce tanning and add color to hair and eyes “in the wild,” but the natural version gets broken down in mere minutes. Not so great if you’re trying to turn it into a therapeutic agent. 

The team had to change that to make α-MSH viable. First came Melanotan 1, which already had a longer half life. Then came Melanotan 2 — smaller, stronger, and even more stable. There’s another difference, too. Melanotan 1 is precise. It works on the MC1R receptor in the skin. Melanotan 2 hits the MC3R and MC4R receptors as well. [1]

That broad action is why the first studies discovered the peptide had other (and quite unexpected!) effects, too. Beyond inducing a tan, Melanocortin also boosts sexual arousal. Plus, it slashes appetite and helps burn fat. Those effects were too interesting to be ignored. They led to further study — and the later creation of another peptide now called Bremelanotide. (But that’s another story for another page.)

What Applications Has Melanotan-2 Research Looked at So Far (and What Could Be Next)?

“Pandora’s box” + “research possibilities?” Definitely! The broad receptor activity Melanotan 2 demonstrates (especially when compared to Melanotan 1, which is much more selective) quickly made researchers investigate its other potential uses. A peptide that began its life as a sunless tanning project caught the interest of researchers looking at metabolism and sexual function and satisfaction, too. 

Lots of Melanotan 2 studies have been done over the years, but these? They’re some of the most interesting — especially if you’re wondering the directions future research might take. 

Melanotan 2 Research Into Sunless Tanning and Photoprotection 

Every study ever conducted into the effects of Melanotan 2 confirms that it succeeds in doing what it was created for. Melanotan 2 induces a deep, lasting tan — and it doesn’t take much of the peptide to achieve that effect. Low doses, given every other day, get the job done. [2]

Melanotan 2 was created to reduce the risk of skin cancer (in fair-skinned people, but also folks who live in sun-heavy places), but people everywhere want suntans for all sorts of reasons. If you know anything about the peptide, you’re already bound to be familiar with its popularity among bodybuilders (who use it for contest prep) and others who want sun-free tans. Studies have also investigated the compound for more serious medical reasons, though. They include the treatment of photosensitivity disorder, in which sun exposure can cause extreme pain. [3]

The Metabolic Impact of Melanotan 2 — Including Appetite Reduction

This initially unexpected effect actually has a simple cause. Melanotan 2 activates the MC4R receptors. Those are present the hypothalamus, involved in homeostasis — of which metabolic regulation is one part.

Early Melanotan 2 studies almost exclusively zeroed in on its tanning effects, but later research with mouse models done in the 2020s has started to look at the peptide’s appetite reduction results. Mice given Melanotan 2 eat less — and when they’ve had enough calories, they no longer desperately go around looking for food. [4] Could it do the same for people? No clinical trials have materialized so far, but it would be beyond interesting to find out.

Meanwhile, here’s another worthwhile finding. Mice given Melanotan 2 also have better insulin sensitivity — and healthier blood sugar levels. That? It demonstrates a metabolic effect that goes deeper than killing cravings. Pretty exciting! [5]

Libido, Sexual Function, and the Road to Bremelanotide

This is the effect that gets everyone excited — on a theoretical level, obviously, but also physically (if you just so happened to be a man enrolled in an early Melanotan 2 study). Eighty percent of men treated with Melanotan 2 developed “clinically apparent” and seemingly spontaneous erections. No stimulation required. The mean duration? A grand total of 38 minutes. [6]

That surprise finding triggered a whole host of further research — which eventually led to the development of Bremelanotide (PT-141), a novel peptide now FDA-approved to treat hypoactive sexual desire disorder in women. [7] That’s expanded the possibilities, but it never took Melanotan II off the table as an interesting research compound. 

A peptide that creates a sunless tan, but also controls appetite and boosts sexual desire? Let’s just say that it has obvious appeal for a wide variety of reasons. It’s no surprise that some informally call it the Barbie peptide — although “Ken” would perhaps be more fitting. Melanotan 2 is still only used in research. No clinical applications have been approved. But if they were, many would be rushing to try it. 

Where Could Melanotan 2 Research Go Next?

Good question. All PT-141 research is a direct extension of Melanotan 2 research — by virtue of the fact that Melanotan 2 directly spurred its creation. There’s a lot of that going on right now. Melanotan 2 itself still has relatively unexplored potential, mind you. 

Among them? Some studies hint that melanocortin agonists (and Melanotan 2 is one of them) act as anti-inflammatories. That could put the peptide on the map in terms of arthritis studies and research into other chronic inflammatory conditions. [8]

There’s more, too. Research has proven that MC4R receptors play some roles in the development and expression of stress, anxiety, and depression. [9] Perhaps future Melanotan 2 research could puzzle out if the peptide has the power to boost mood and mental health, in rodent models? Or if activating MC4R has any application in addiction recovery medicine?

Those are bold questions for ambitious researchers. They still need answering. They definitely show that Melanotan 2 is a bit more than a simple tanning agent, however — although that alone is also plenty interesting. 

How Have Melanotan II Studies Administered the Peptide?

That’s another important question, because the delivery method affects all sorts of research variables. Bioavailability (how well the model can absorb the compound), onset of action, and adverse effects are among them, but so are the main effects being studied. 

Almost all preclinical and clinical studies have used subcutaneous injections as the delivery method. In this case, Melanotan 2 is reconstituted with bacteriostatic water (which makes it available for multi-dose use) and then injected into the fatty tissue just underneath the skin. 

That same method has been used for human trials and rodent studies. It gives the peptide an easy way in, so researchers can observe its systemic effects — from melanocytes in the skin all the way to the hypothalamus, where its sexual effects get activated. 

Some research has looked into other delivery methods, too. The successor peptide Bremelanotide, which only targets sexual function without any tanning effects, has been developed as a nasal spray, and the possibility that Melanotan 2 could also be given this way has been raised. For now, however, suBQ delivery is still the most common method. 

How Do Researchers Determine Dosing Protocols for Melanotan 2?

Developing a protocol that was both effective and tolerable was one of the first challenges for the early trials. The most common side effects observed in the early days were nausea, facial flushing, and (interestingly enough) spontaneous yawning. Researchers had to account for those as they came up with a dosing protocol that would minimize them. 

The search for the “sweet spot” uses a strategy of escalation. One important study started with 0.10 mg, and then increased it in steps to 0.16 mg, 0.30 mg, 0.50 mg, and at the end a maintenance dose of 1.0 mg. Daily dosing was used in some trials, while others went for dosing every other day. 

Protocols for Melanotan 2 can also be precisely based on the subject’s body weight. That’s true for rodent models, where this method is the default, but it’s also been used in some human trials. Regimens you’ll see mentioned in the studies we’ve referenced, especially to observe erectile effects, involved escalating dosing in 0.005 mg per kg increments, to 0.03 mg per kg and one to 0.025 mg per kg. (For reference, that would translate to 1 final dose of 2.1 for a 70 kg person.)

The most common study lengths are between one and three weeks. Maintenance dosing can go on for significantly longer. That’s usually for tanning effects. Sexual functioning effects are more often studied with a single dose (which can be repeated), because they’re acute rather than chronic. 

Want to Learn More?

Future research directions might well look at Melanotan 2 as a combination therapy. After PT-141, AKA Bremelanotide, became a “spin-off” compound for treating sexual dysfunction, research could also lead to yet more compounds based on the successes of Melanotan 2. 

Research into Melanotan 2 isn’t anywhere close to finished. There’s always more to discover. Because biological systems don’t work in isolation. The same receptors that give people suntans also impact appetite. And metabolic health. And libido. 

Nearly all peptide research so far has these kinds of unexpected results. That’s exactly why peptides are so interesting. Still want to find out more? Researchers can, of course, translate theory into action — we provide pharmaceutical-grade peptides to make the next round of discoveries possible. Everyone else should know the studies already out make for worthwhile reading. 

FAQs

Scientific References and Sources

1. https://www.sciencedirect.com/science/article/abs/pii/S0196978105004602[↩]
2. https://www.sciencedirect.com/science/article/abs/pii/0024320596001609[↩]
3. https://www.tandfonline.com/doi/full/10.1080/17512433.2021.1879638#abstract[↩]
4. https://www.sciencedirect.com/science/article/abs/pii/S0143417922000646[↩]
5. https://link.springer.com/article/10.1007/s00125-005-1838-8[↩]
6. https://www.auajournals.org/doi/abs/10.1016/S0022-5347(01)62903-3[↩]
7. https://journals.lww.com/greenjournal/fulltext/2019/11000/long_term_safety_and_efficacy_of_bremelanotide_for.3.aspx[↩]
8. https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2019.00683/full[↩]
9. https://www.sciencedirect.com/science/article/abs/pii/S019697810500241X[↩]