Based on animal studies and experimental research, this article will detail the primary properties of Melanotan 1 (MT-I) and Melanotan 2 (MT-II), as they have been hypothesized.

Below, you will also find detailed information on Melanotan's structure, processes, potential effects, and research findings. Read on to find out who we recommend as the best sources for research on Melanotan 1 and Melanotan 2.
 
Melanotan Peptides: Mechanism of Action
 
Melanotans, namely MT-I and MT-II, are synthetic peptides that have been hypothesized to mimic the effects of the natural alpha-melanocyte stimulating hormone (α-MSH). Research suggests that the connection between α-MSH and melanocortin receptors may allow it to play an inherent function in several physiological pathways. Melanin production, libido enhancement, and food intake control are all theorized examples of such processes. Investigations purport that MT-I may be a structural and functional mimic of α-MSH. It is also called [Nle4, D-Phe7]-α-MSH or afamelanotide (CUV1647). The most important things to remember with this peptide are:
 

  • The peptide has thirteen amino acids, with norleucine and D-phenylalanine replacing methionine and L phenylalanine at positions four and seven in the linear arrangement.
  • The primary regulator of melanogenesis, the melanocortin receptor 1 (MC1R), is amplified in its affinity and half-life by structural modifications to MT-I.

 
The MT-I molecule has nine amino acids, whereas MT-II is a seven-amino-acid cyclic peptide that only retains the His-D-Phe-Arg-Trp sequence (positions three to six). Researchers need to be aware of the following:
 

  • Aspartic acid's side-chain carboxyl group at position 2 and lysine's side-chain amino group at position 7 join to create a lactam bridge, which causes six of MT-seven II's amino acids to form a ring, making the peptide cyclic.
  • This arrangement may improve MT-II's binding affinity to MC1R, MC3R, and MC4R, among others.
  • Research on MT-II is ongoing for several possible indications, such as pigmentation and melanin production and libido management. 
  • Developing these peptides mainly aimed to investigate and use their melanogenic (tanner) properties. However, their complex interactions with melanocortin receptors have sparked debates about their possible uses and consequences in various fields of study.

 
Melanotan Peptides: Research
 
Investigations purport that MT-I and MT-II may interact with melanocortin receptors (MCRs), which are important signaling channels in many biological processes, and they may exercise their many physiological effects in this manner. Melanocortin receptors (MC1R–MC5R) are believed to be involved in several physiological processes:
 

  • MC1R: Melanocyte-specific, promotes melanin production.
  • MC2R: Cortisol is produced by this receptor, mostly in the adrenal cortex.
  • MC3R is a gene that regulates energy balance and hunger. 
  • MC4R: A region of the central nervous system that regulates energy balance and sexual behavior; it is located in the hypothalamus.
  • MC5R: Although it is thought to be involved in exocrine function, its precise physiological function is still largely unknown despite its expression in numerous tissues.

 
Findings imply that increased pigmentation may result from melanin production, which Melanotan 1 might mainly accomplish via binding to the MC1R receptor. The peptide has been hypothesized to promote enhanced melanin formation even in the absence of UV radiation and light, and its affinity for the MC1R is speculated to be stronger than that of α-MSH.
 
Scientists also speculate that the increased melanin absorbs UV light and has been deemed helpful in photosensitive circumstances. Melanotan 2's receptor specificity is more generalized; however, it has been theorized to interact most prominently with the MC1, MC3, and MC4 receptors.
 
MT-II binding to MC4R has suggested promising results in regulating sexual behaviors in female animal research models and erections in males, whereas its interaction with MC1R might promote melanogenesis. Additionally, changes in hunger and metabolic processes have been linked to the interaction of MT-II with MC3R and MC4R. The involvement of MT-multi-receptor II has been asserted to cause various physiological consequences. 
 
By uniquely acting on the melanocortin receptors, MT-I and MT-II have suggested several promising properties. The most significant properties of both substances are detailed below.
 
Melanotan Peptides and Skin Cells
 
It has been speculated that both MT-I and MT-II may enhance pigmentation by stimulating the MC1R. Investigations purport that while MT-I may cause pigmentation even in the absence of UV rays, studies have indicated that it may reduce the number of burnt skin cells by 47% after exposure to UV/sunlight. This is because MT-I has been hypothesized to enhance skin melanin production, which absorbs UV rays and reduces its oxidative and harmful effects. The photoprotective properties of MT-I have prompted extensive study into its possible uses:
 

  • Three phase-3 clinical studies with 244 research models with the disease were the basis for its testing. Protoporphyrin IX accumulates in the blood and skin of EPP research models due to an enzyme shortage. Exposure to sunlight or ultraviolet radiation causes this chemical to absorb light, producing reactive oxygen species that harm the skin. This may lead to short-term discomfort and longer-term consequences, such as scarring. Melanin production in the skin is theorized to be enhanced by MT-I, which may boost UV absorption and alleviate the symptoms above.
  • An itchy rash may develop due to an aberrant immunological response to ultraviolet radiation in research models with polymorphic light eruption (PLE), particularly after periods of infrequent sun exposure. In a 2010 phase-3 study of research models with PLE, MT-I was given as an implant for four months and was speculated to lessen the intensity of the rash.
  • For acne vulgaris, MT-I indicated promise in a 2012 pilot study including three research subjects in reducing inflammation in acne lesions. Nevertheless, the precise way the peptide may decrease skin irritation remains a mystery. Researchers need further experiments to validate this possible impact.

 
Click here to be redirected to the Biotech Peptides website for more educational articles. Researchers interested in further studying Melanotan peptides may find them on the website at the highest quality and best prices.
 
References
 
[i] Habbema, L., Halk, A. B., Neumann, M., & Bergman, W. (2017). Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review. International journal of dermatology, 56(10), 975–980. https://doi.org/10.1111/ijd.13585
 
[ii] Yeo, G. S. H., Chao, D. H. M., Siegert, A. M., Koerperich, Z. M., Ericson, M. D., Simonds, S. E., Larson, C. M., Luquet, S., Clarke, I., Sharma, S., Clément, K., Cowley, M. A., Haskell-Luevano, C., Van Der Ploeg, L., & Adan, R. A. H. (2021). The melanocortin pathway and energy homeostasis: From discovery to obesity therapy. Molecular metabolism, 48, 101206. 
 
[iii] Minder, E. I., & Schneider-Yin, X. (2015). Afamelanotide (CUV1647) in dermal phototoxicity of erythropoietic protoporphyria. Expert review of clinical pharmacology, 8(1), 43–53. https://doi.org/10.1586/17512433.2014.956089
 
[iv] Modi, M. E., Inoue, K., Barrett, C. E., Kittelberger, K. A., Smith, D. G., Landgraf, R., & Young, L. J. (2015). Melanocortin Receptor Agonists Facilitate Oxytocin[1]Dependent Partner Preference Formation in the Prairie Vole. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 40(8), 1856–1865. 
 
[v] Côté, I., Sakarya, Y., Kirichenko, N., Morgan, D., Carter, C. S., Tümer, N., & Scarpace, P. J. (2017). Activation of the central melanocortin system chronically reduces body mass without the necessity of long-term caloric restriction. Canadian journal of physiology and pharmacology, 95(2), 206–214
 
[vi] Ji, L. Q., Hong, Y., & Tao, Y. X. (2022). Melanocortin-5 Receptor: Pharmacology and Its Regulation of Energy Metabolism. International journal of molecular sciences, 23(15), 8727. 
 
[vii] Mun, Y., Kim, W., & Shin, D. (2023). Melanocortin 1 Receptor (MC1R): Pharmacological and Therapeutic Aspects. International journal of molecular sciences, 24(15), 12152. 
 
[viii] Lane, A. M., McKay, J. T., & Bonkovsky, H. L. (2016). Advances in the management of erythropoietic protoporphyria – role of afamelanotide. The application of clinical genetics, 9, 179–189. 
 
[ix] Ückert, S., Bannowsky, A., Albrecht, K., & Kuczyk, M. A. (2014). Melanocortin receptor agonists in the treatment of male and female sexual dysfunctions: results from basic research and clinical studies. Expert opinion on investigational drugs, 23(11), 1477– 1483. 

 
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