Melanotan II was developed by researchers at the University of Arizona. Melanotan II is an analog of the peptide hormone that provides a therapeutic tan with ability to lower the risk of skin cancer. Melanocyte stimulating peptide also plays an important role in regulating desire in men and women by antagonizing melanocortin receptors in the brain. Melanotan II also decreases body fat and is known to suppress the appetite. Melanotan II is a cyclic lactyam analog of alpha-MSH with the amino acid sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2.

Melanotan II is in a class of peptide hormones known as Melanocortins (MCs). Melanocortins (MCs) are multifunctional peptide hormones that regulate a diversity of physiological functions. The University of Arizona improved the peptide even further and developed Melanotan II an effective sunless tanning agent. Both Melanotan I and II are synthetic hormones of melanocyte stimulating hormone that are responsible for darkening skin pigment when exposed to sunlight. Melanotan I is a linear, full length peptide [containing 13 amino acids]. Melanotan II is a shortened, circular version of melanocyte stimulating peptide.

Melanotan is a synthetic hormone that mimics the action of MSH, or melanocyte-stimulating hormone which is responsible for darkening the pigments of the skin. Typically when skin is exposed to UltaViolet radiation (the sun or tanning beds) skin will release melanin from melanocytes as a natural defense from absorbing an excess amount of solar radiation. This natural defense to is what leads to tanning or a darkening of your skin. Melanotan is a peptide hormone which similuates melanocyte response with less damage from the sun.

Naturally occurring alpha-melanocyte stimulating hormone (α-MSH) causes melanogenesis, a process by tanning cells (melanocytes) produce pigment (melanin/eumelanin). Melanotan synthetic peptide administation has been proven to be an effective method to tan particular skin types. Natural alpha-MSH had too short a half life in the body to be practical as a therapeutic peptide. More potent and stable alternative, Melanotan II, would be more practical.

After synthesizing and screening hundreds of molecules, the researchers found a peptide that after trials and testing seemed to not only be safe but also approximately 1,000 times more potent than natural α-MSH. They dubbed this new peptide Melanotan. Since discovery, numerous studies show no toxic effect. Skin cancer (melanoma) is a major health concern, tanning peptides are expected to be used to provide phototherapy. Melanotan will do this by stimulating the body’s natural tanning mechanism to create a tan without first needing exposure to harmful levels of UV radiation. This in turn may reduce the potential for skin damage that can eventually lead to skin cancer.

The Arizona Cancer Center is working with Melanotan not only as a drug with cosmetic applications but in order to reduce the risk of skin cancer. They feel that if fair skinned people take Melanotan it will offer them the protective benefit of a tan without the harm of sun exposure. In essence, it could protect people by providing them with a slight sunless tan that would make them less prone to burn with their day-to-day exposure to the sun.

While testing peptide Melanotan II an unexpected side effect of spontaneous erections in men occured. The American Association of Urologists tested this peptide extensive and found that it did not change the bloodflow or selectively expand or restrict capilaries in the same manner PDE5 treat erectile dysfunction. Melanocortin peptides work by sending a signal to the brain which causes the body to naturally secrete the hormone which enhances aphrodisiac. Further testing found women also increased sexual desire and genital arousal. Evaluation is currently being done with this peptide in hopes of developing a new type of erectile dysfunction drug, however the Arizona Cancer Center suspended all development of Melanotan II as a tanning agent.

Melanotan II can enhance sexual function in human males and females (increased levels of sexual desire and genital arousal). Unlike other sexual-enhancement drugs, Melanotan works at the brain, thus eliciting a rather natural sexual response with minimal undesirable side effects. Actions of the peptide were discovered accidentally while studying the effects of the related analogs on tan research.

The Arizona Cancer Center’s research has found Melanotan to be effective in promoting skin pigmentation with little or no risk, however it’s role in actually preventing skin cancer has not yet been determined. No long term study or instruction exists for Melanotan tanning peptide analogs.

This peptide has been going through extensive testing and research over the past ten years, however it is still not approved for use by any regulatory agency.
Researchers at the University of Arizona are no longer conducting research with Melanotan, although research continues for Bremelanotide (PT-141).

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