The Melanotan Peptides: A Product Comparison


Melanotan 2, Melanotan 1, and PT-141 are all melanocortinergic peptides. That is, they are analogues of the natural hormone alpha-MSH, exerting their effects in the body through binding to specific melanocortin receptors. Certainly, all three peptides share various commonalities, the most prominent of which is the aforementioned mechanism of action. Additionally, each peptide has been shown to have similar side effects in study subjects, particularly when taken in high doses. Though the prevalence of these side effects varies between the three (Melanotan 1 is considered to have the least prominent side effects, for example), flushing, dizziness, lethargy, and nausea are all possible negative effects that may arise from high dosages of any of these alpha-MSH analogues.

However, perhaps more important than the similarities between these peptides are the differences between them. Certainly, in terms of the effects achieved through the use of melanotan peptides, these differences will dictate which peptide is most suitable for use to attain specific results. For example, both Melanotan 2 and PT-141 have been studied in clinical trials for development as a possible future treatment for Female Sexual Arousal Disorder due to their libido enhancing effects observed in clinical study. However, Melanotan 1 does not exhibit any effects on libido or sexual arousal, making it unsuitable for development towards this particular purpose. Still, both Melanotan 1 and Melanotan 2 elicit powerful skin tanning effects in study subjects, while PT-141 does not exhibit any skin pigmentation or tanning activity. Clearly, it is vital to become fully versed in these differentiating factors.



Melanotan 2 Vs. Melanotan 1

First, both melanotan peptides exhibit similarly substantial skin pigmentation and tanning results. This is due to their identical mechanisms of action in regards to this effect. MT-I and MT-II both enhance the body’s natural production of eumelanin, the most common type of melanin in the skin, through their affinity for binding to the melanocortin 1 receptor (MC1R). As melanin is the pigment responsible for natural skin color and the deep bronze character of a tan, the more eumelanin (and thus melanin) there is in the skin, the darker the skin becomes in color. As a result, Melanotan 1 and Melanotan 2 exhibit near identical skin tanning effects and have been studied extensively in clinical trials for the purpose of eliciting a suntan in subjects.

On the other hand, the differences between Melanotan 1 and Melanotan 2 are commonly less known. However, they can ultimately be linked to their differing binding characteristics in regards to the body’s numerous melanocortin receptors. Essentially, Melanotan 1 only has the previously mentioned tanning effects. This is because it only binds to the melanocortin 1 receptor, which subsequently affects melanin production and skin pigmentation. Conversely, Melanotan 2 exhibits powerful effects on sexual arousal, libido, and fat loss in addition to enhancing skin tanning. This is due to the fact that, unlike Melanotan 1, MT-II has high affinity for melanocortin receptors 3 and 4 in addition to melanocortin receptor 1. Though the exact mechanisms of action by which the affinity for receptor 3 and receptor 4 causes these effects are still being revealed, Melanotan 2’s impact on enhanced erectile function, increased sexual desire, and enhanced sexual response can all be traced back to its binding affinity for these key receptors. Likewise, its impact on fat loss and appetite suppression can be linked to these receptors as well, particularly melanocortin receptor 4 (MC4R). Ultimately, it is because Melanotan 2 binds to more melanocortin receptors in addition to MC1R that it is able to exhibit more effects in addition to skin tanning.

As previously mentioned, both melanotan peptides have been observed to cause similar side effects in clinical studies, particularly lightheadedness, flushing, and nausea of a transient nature. Importantly, however, Melanotan 1 has been reported to have significantly less occurrences of these side effects, and, when they do occur, they are often reported to be less intense and persistent than with Melanotan 2. Though it has not been definitively proven in clinical study, it can be hypothesized that this reduction in side effects can again be traced to the fewer number of melanocortin receptors activated. It is important to note that all melanocortinergic peptides have been reported to be very well tolerated in clinical study, however, and that side effects typically only become bothersome at very high dosages above recommended maximums.



Melanotan 2 Vs. PT-141

As previously mentioned, Melanotan 2 and PT-141 share essentially identical facilitative effects on sexual function. Both peptides have been shown in clinical study to enhance erectile function in men while increasing sexual desire and response in both men and women. Importantly, these peptides not only enhance the physical sexual response, i.e. sexual arousal, but they have also been observed to increase the desire for sex, also referred to as sex drive or libido. Perhaps most critically, each has been shown to elicit these effects in both men and women.

PT-141 and Melanotan 2 have both been extensively researched for their ability to initiate penile erections in men. This effect is linked again to their binding affinity for specific melanocortin receptors in the body, particularly MC3R and MC4R. After administration, an increase in nitric oxide production in penile erectile tissue has been shown to occur, facilitating vasodilation and increased blood flow, resulting in enhanced and increased erectile function.

Further, both peptides have been shown to increase sexual desire in both sexes, independent from physical arousal or stimulation. Studies have shown women to be subjectively more satisfied with their level of sexual arousal and more likely to desire sex after administration compared to a placebo. Indeed, studies have shown similar libido enhancing effects to occur in men as well.

The difference between Melanotan 2 and PT-141 is that the latter is a metabolite of the former with only its sexual function enhancing properties. That is, PT-141 is a structurally altered version of Melanotan 2 designed to have the aforementioned sexual effects without any skin pigmentation or tanning activity. This is due to the shared affinity of both peptides for the MC3R and MC4R, and, on the other hand, the distinct affinity of Melanotan 2 for the MC1R, the receptor to which tanning effects can be traced. PT-141 has been intentionally designed to have no affinity for the melanocortin 1 receptor, giving it no effect on melanin production.

Clinical research has indicated that side effects are quite similar between the two peptides. The common side effects of temporary lightheadedness, nausea, and flushing may occur with either peptide, with the likelihood increasing as the dose goes up. At comparable dosage levels, the incidence and intensity of these effects has been reported to be essentially the same when averaging out the research data. However, occurrence of side effects is often highly subjective and can vary greatly among individual subjects. This is why a small initial dose is often recommended.



PT-141 Vs. Melanotan 1

Melanotan 1 and PT-141 are the most different of the melanocortinergic peptides. Their similarities extend mainly to their structure and derivation. For instance, both peptides are alpha-MSH analogues that are metabolites of Melanotan 2, meaning that they are variations of the MT-II peptide with certain alterations. Further, both peptides bind to specific melanocortin receptors; however, they each have affinity for different receptors. Finally, like all alpha-MSH analogues, side effects of fleeting nausea or flushing may occur following the administration of each. Still, as mentioned previously, Melanotan 1 is often reported to be less severe in this regard.

The differences between PT-141 and Melanotan 1 are all in their respective effects. PT-141 has been shown to exert its effects on sexual arousal and motivation, whereas Melanotan 1 has been shown to stimulate melanin production and skin tanning. This is due to the fact that PT-141 has binding affinity for the melanocortin receptors 3 and 4 while Melanotan 1 binds only to melanocortin receptor 1. Though an overly simplified perspective, Melanotan 1 can essentially be thought of as Melanotan 2 without any sexual effects. Likewise, PT-141 can be thought of as Melanotan 2 without any effects on tanning or skin pigmentation. As Melanotan 2 binds to the combined melanocortin receptors of MT-I and PT-141, its effects are essentially an amalgam of the two.