Key Benefits
Biologic Description
Melanotan II (MT-II) is a synthetic analogue of the alpha-melanocyte-stimulating hormone (α-MSH). It primarily functions by mimicking the effects of naturally occurring melanocortins, leading to increased melanin production in the body. This peptide is of interest due to its effects on pigmentation, appetite regulation, and sexual arousal. MT-II acts on melanocortin receptors (MCRs), particularly MC1R, MC3R, and MC4R. MC1R activation is primarily involved in skin pigmentation, leading to increased production of melanin in melanocytes, while MC3R and MC4R activation are associated with energy homeostasis and sexual function, with MC4R activation linked to appetite suppression and increased libido.
Upon binding to MC1R on melanocytes, MT-II triggers a cascade via G-protein-coupled receptors (GPCRs). This binding stimulates adenylate cyclase, increasing cyclic AMP (cAMP) levels. Elevated cAMP activates Protein Kinase A (PKA), which in turn phosphorylates cAMP response element-binding protein (CREB). CREB activates the microphthalmia-associated transcription factor (MITF), a key regulator in melanin synthesis. MITF upregulates tyrosinase, tyrosinase-related protein 1 (TRP-1), and dopachrome tautomerase (TRP-2), enzymes crucial for melanin production.
Several genes are involved in this process. The MC1R gene encodes the melanocortin 1 receptor, and variants in this gene can affect the efficacy of MT-II. The MITF gene encodes the MITF transcription factor, essential for melanocyte function and melanin synthesis. The TYR, TRP1, and TRP2 genes encode tyrosinase and related proteins critical for melanin biosynthesis. MT-II binding to MC1R leads to increased expression of MITF, TYR, TRP1, and TRP2, enhancing the melanin synthesis pathway.
The physiological effects of MT-II are diverse. It promotes the synthesis of eumelanin, resulting in darker skin pigmentation, and increased melanin provides protection against UV radiation. In terms of appetite and energy regulation, MT-II's interaction with MC4R in the hypothalamus suppresses appetite and influences energy expenditure. Additionally, MT-II's activation of MC3R and MC4R has been shown to increase sexual arousal and erectile function.
Melanotan II is a potent analogue of α-MSH that exerts its effects through the melanocortin receptor system, primarily affecting pigmentation, appetite, and sexual function. Its action involves a complex interplay of receptor activation, signal transduction via the cAMP pathway, and the regulation of key genes involved in melanin production. Through these mechanisms, MT-II influences several physiological processes, making it a molecule of significant interest in both therapeutic and research contexts.
Dosage Guidelines
The general dosage protocol for Melanotan II begins with a starting dose to assess tolerance. Initially, an individual should administer a test dose at 0.25 mg (250 mcg) via subcutaneous injection, preferably in the evening to mitigate any potential nausea. Following this, the loading phase involves administering 0.5 mg (500 mcg) every other day for 1-2 weeks or until the desired level of pigmentation is achieved. Once the desired pigmentation is reached, the maintenance phase begins, where a dose of 0.5 mg (500 mcg) is administered once or twice a week as needed to maintain the pigmentation. It is advisable to cycle the usage by taking breaks after several weeks to allow the body to reset and avoid receptor desensitization, then repeating the initial cycle if necessary.
250 - 500 mcg
Loading: Daily
Maintenance: Once a Week
4-8 Weeks
Side Effects
Melanotan II, while effective in increasing pigmentation, appetite suppression, and enhancing sexual function, is not without its potential side effects. Common side effects include nausea, facial flushing, and increased freckles or moles. These usually subside over time, but persistent or worsening symptoms should prompt consultation with a healthcare provider.
More serious, though rare, side effects include severe skin reactions, changes in mole appearance, and potential cardiovascular issues due to its impact on blood pressure and heart rate. Users might also experience fatigue, dizziness, or gastrointestinal disturbances, especially during the initial stages of administration.
One significant but rare side effect associated with Melanotan II is rhabdomyolysis, a condition characterized by the breakdown of muscle tissue leading to the release of muscle fiber contents into the bloodstream. This can result in severe complications such as kidney damage. Rhabdomyolysis symptoms include muscle pain, weakness, swelling, and dark-colored urine. The connection between Melanotan II and rhabdomyolysis is thought to be related to the peptide's potential to induce extreme muscle contractions or prolonged muscle activity, which can stress and damage muscle fibers.
In addition to these potential effects, users should be aware of the peptide's impact on existing moles and freckles, which may become darker or more numerous. This necessitates regular skin checks to monitor any unusual changes, given the potential risk of melanoma. Other concerns include the peptide's interactions with other medications and its impact on individuals with pre-existing conditions, particularly those affecting the cardiovascular or renal systems.
References:
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Dorr, R. T., Lines, R., Levine, N., Schram, K., Hopp, M. L., Powell, M. B., ... & Hruby, V. J. (2004). Evaluation of Melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sciences, 75(24), 295-300. doi:10.1016/j.lfs.2004.02.017
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Langan, E. A., Ramot, Y., Goffin, V., Griffiths, C. E., & Foitzik, K. (2010). The role of prolactin in the skin. Frontiers in Endocrinology, 1, 115. doi:10.3389/fendo.2010.00115
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Rudman, S. M., Philpott, M. P., Thomas, G. A., & Keohane, S. G. (2003). Melanotan, a superpotent melanotropic peptide: A physicochemical and pharmacokinetic evaluation. Journal of Clinical Endocrinology & Metabolism, 88(12), 6009-6014. doi:10.1210/jc.2003-030237
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MacNeil, S., Hardman, J., & Wilson, C. (2008). The effects of melanotan-II, a synthetic melanocortin peptide, on human melanocytes and melanoma cells in culture. Journal of Investigative Dermatology, 128(11), 2763-2768. doi:10.1038/jid.2008.151
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Sonda, S., Komericki, P., & Aberer, W. (2012). Severe adverse effects after misuse of melanotan II: case series and review of the literature. Journal of the American Academy of Dermatology, 67(5), e191-e193. doi:10.1016/j.jaad.2011.12.035
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Yen, S., Jansen, T., & Chen, Y. (2017). Rhabdomyolysis associated with the use of melanotan-II. BMJ Case Reports, 2017, bcr-2016-218301. doi:10.1136/bcr-2016-218301