Background

Melanotan II was first developed at the University of Arizona. Various studies conducted at the institution confirmed that the best defence against skin cancer was melanin activated in the skin, a tan. The researchers assumed that an effective procedure to reduce the rates of skin cancer in individuals would be by inducing the body’s natural pigmentary system to produce a tan that would be protective before exposure to UV. Melanogenesis is a process by which the skin’s pigment cells (melanocytes) produce the hormone α-MSH naturally causes the skin's pigment (melanin).

After numerous clinical trials by administration of the endogenous hormone to the body, the scientists found that though it appeared to work, α-MSH had a very short half-life in the body to be practical as a therapeutic drug. Therefore, they opted to look for a more stable and potent alternative that would be more practical. Subsequently, after numerous trials, they developed Melanotan I and after that Melanotan II.

Mechanism of action

Melanotan II acts as a non-selective agonist of the melanocortin receptors MC1, MC3, MC4, and MC5.

Melanotan II produces melanogenesis by activation of the MC1 receptor, whereas its clinically documented sexual effects are thought to be related to its ability to activate the MC4 receptor (though the MC3 is thought to also possibly be involved).

Other effects of melanotan II, mostly regarded as adverse effects,  include flushing, nausea, vomiting, stretching, yawning, and loss of appetite (the last via activation of MC4).

Melanotan is a lab-made chemical. It is similar to a hormone found in the body. It was originally made as a drug to help treat certain skin conditions. It is also sold over the internet as a supplement.

Melanotan is commonly used for skin tanning. It is also used to produce erections in men with erectile dysfunction (ED), for rosacea, for fibromyalgia, and other conditions, but there is no good scientific evidence to support most of these uses. There is also concern that melanotan might not be safe when used as a shot under the skin. 

Malanotan II is used for tanning of the skin and producing of erections in men with erectile dysfunction when administered as a shot under the skin. Malanotan II is safe when used under strict medical supervision for treating erectile dysfunction. However, it may cause stomach cramps, tiredness, nausea, spontaneous erections of the penis, and darkened skin.    

Side effects

Short term side effects after administration include:

Facial flushing

Reduced appetite, nausea and vomiting

In males, spontaneous erections 1-5 hours after administration (priapism), associated with yawning and stretching complex

Long term, there is concern that melanotan II may increase the risk of:

Melanoma – a potentially serious form of skin cancer

Deepening of the color of moles, new moles and atypical melanocytic naevi

Melanonychia – brown to black discoloration of one or more nails

Suggested usage: daily for 1 - 2 weeks then one to two times weekly for maintenance.

Clinical Use

Melanotan II has been a new treatment for rosacea discussed in the various rosacea support groups on the internet.

Melanotan I and Melanotan II are both analogs of the peptide hormone alpha-melanocyte stimulating hormone (a-MSH) that tend to induce skin tanning. Melanotan II has the additional effect of increasing libido.

Melanotan II is an α-MSH analog which underwent clinical trials for the treatment of erectile dysfunction. Preliminary double-blind, placebo-controlled studies demonstrated the efficacy of melanotan in inducing penile erection in men with erectile dysfunction, although in a very restricted population.Unfortunately, there are no experimental data on the mode of action of melanotan II, as melanotan II is the first α-MSH agonist inducing penile erection when injected peripherally.

Illustration of the proerectile effect of melanotan II (MT-II) in humans. Placebo (A) or MT-II (B, 25 ug/kg and C, 133 ug/kg) was injected subcutaneously in patients and RigiScan recording was performed from 6 h. Apparent erections developed in 8 of 10 men treated with MT-II. (Reproduced with permission from Wessells H et al. Effect of an alphamelanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction. Urology 2000; 56:641–646.)