Class of Compound:
Mechanism of Action:
Melanotan II is an agonist of melanocortin receptors 1 and 4 (MC-1R and MC-4R), which respectively regulate melanin production and male erectile function. It is also believed to stimulate MC-3R, which affects appetite and energy levels.
Also Known As
Melanotan-II, MT II, MT-II, Melanotan (MT)-II, 121062-08-6.
- Skin tanning
- Sexual arousal
- Appetite control
- Compulsive/addictive behavior
- Cognitive disorders
- No long-term safety studies
- Uneven skin pigmentation
- Development of new moles or darkening of preexisting moles
What is Melanotan 2?
Melanotan 2 is a synthetic analogue of alpha-melanocyte-stimulating hormone (α-MSH). The molecule was first developed in the 1980s by University of Arizona researchers, who were looking to clarify the nature and role of the melanocortin receptors in physiological functions. Namely, the peptide was intended to be used as a sunless tanning agent, but was subsequently found to strongly affect sexual function and appetite .
Melanotan 2 (MT-II) should not be confused with another α-MSH analogue, melanotan I (MT-I), which is a linear peptide of 13 amino acids in length. MT-I is identical to α-MSH except that it features norleucine instead of methionine in the fourth position, and D-phenylalanine instead of L-phenylalanine in the seventh position.
In contrast, MT II is a cyclic truncated peptide of just seven amino acids and features a lactam ring .
What Does Melanotan 2 Do?
While the bulk of research on both melanotan molecules has focused on their role as a tanning agent and corresponding potential to lower the risk of skin cancer , clinical studies involving MT-II have investigated its abilities to decrease appetite, increase libido, and diagnose and treat male erectile dysfunction [1, 3].
Melanotan II is up to 1000 times more potent than endogenous α-MSH, binding to the body’s melanocortin receptors in varying degrees, exerting varied effects. MT-II binds primarily to the MC1 and MC4 receptors, and to a lesser extent to MC3. Here is a rundown of the receptors in play:
- MC1triggers the darkening of the skin and hair.
- MC3 is involved in the regulation of appetite and energy.
- MC4 affects sexual behavior and male erectile function.
According to studies, MT-II increases pigmentation at a lower cumulative dose than MT-I but has been associated with increased side effects, namely as regards satiety and sexual behavor .
As noted by Mahiques-Santos, the higher incidence of side effects associated with MT-II is due to its being less receptor-specific than MT-I . Palatin Technologies has developed a variation of MT-II called bremelanotide (PT-141), which exhibits MT-II’s specific benefits related to sexual stimulation .
Melanotan 2 Benefits | Clinical Trials
Melanotan II is well-studied and its benefits well-documented:
Increased rate of skin tanning: Melanotan II is known to stimulate the production of melanin, the substance in the skin that determines the rate of tanning and helps prevent sunburn. A 2015 review of melanotan use and associated clinical outcomes identified eighteen clinical trials and twenty-one clinical case presentations demonstrating melanotan II’s action as a synthetic tanning agent .
For instance, in a pilot phase-I clinical study by Dorr et al., three subjects were subcutaneously administered a starting dose of 0.01 mg/kg of MT-II, followed by daily injections of MT-II or placebo for two consecutive weeks. The observed effects included increased tanning, supporting the effectiveness of MT-II as a sunless tanning agent, administered at low doses every other day .
Potential treatment of erectile dysfunction (ED): In a seminal study on the effects of MT-II on sexual function by Wessells H et al., the peptide was administered to 20 men with erectile dysfunction. The study measured penile rigidity and levels of sexual desire, while side effects were self-reported. According to the authors, 17 out of 20 men experienced the desired outcome of penile erection .
A 2006 study by Giuliano et al. found that injections of melanotan 2 (0.1, 0.3, and 1 mg/kg) elicited erectile events in anesthetized rats. Researchers noted that MT-2 also shortened the latency of the first erectile event to occur, concluding that the peptide recruited the central and peripheral melanocortin pathways to achieve this effect .
However, as noted by Mahiques-Santos, while melanotan II has been investigated as a potential ED treatment, it has been largely superseded by a nasally administered molecule (PT-141, Palatin Technologies), an active metabolite of the molecule . There is nonetheless strong research interest in MT-2 as a potential treatment of erectile dysfunction.
Potential autism treatment: A 2019 study by Minakova et al. found that melanotan II reversed autistic features in a maternal immune activation (MIA) mouse model of autism. Researchers continuously administered melanotan II to male MIA mice for seven days and observed a “rescue of social behavioral metrics.'' The authors concluded that MT-II was an effective agent for improving autism-like behavioral deficits in the MIA mouse model of autism, suggesting that further research in this area is warranted .
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Melanotan 2 Side Effects
Melanotan II side effects have been documented in a number of clinical studies and case presentations, as summarized below.
In the Dorr study, three healthy male subjects were subcutaneously administered 0.01 mg/kg of MT-II daily for two consecutive weeks, with one, two, or all three experiencing :
- Spontaneous penile erections
According to the Wessells et al. study (2000), in which MT-II side effects were self-reported, frequent side effects included nausea and yawning, with a low percentage of the men experiencing severe nausea .
Development of new nevi (moles) and changes to pre-existing ones
Several researchers have documented cases where MT-II administration caused the development of new pigmented nevi or pre-existing nevi to grow and darken in color.
For example, Brennan et al. (2015) summarized key findings from a number of clinical case presentations where MT-II caused the darkening of existing nevi. In one such case presentation, Cardones, A.R. and Grichnik, J.M. (2009) documented the case of a 40-year-old male bodybuilder with a medical history of melanoma and multiple dysplastic nevi who reported using melanotan II for bodybuilding competition tan. This male presented with new pigmented nevi and pre-existing nevi also grew and darkened in color; however, these issues subsided once MT-II injections were discontinued .
One case of eruptive melanocytic nevi was summarized by Cousin et al. (2009) , while Langan et al. (2010) noted that MT-II may produce rapidly pigmenting nevi .
Evans-Brown et al. and Langan et al. both described changes to skin moles as one of the potentially harmful effects of melanotan II [11, 12].
In one case study, Dreyer et al. described a single case of melanotan-induced priapism resulting from MT-2 use. The patient presented with acute priapism following abdominal subcutaneous injection of MT-II. According to the authors, the priapism was “low-flow” and managed with cavernosal aspiration and irrigation, followed by intracavernosal injection of phenylephrine. While the patient did not require surgical shunting, he did not recover erectile function when a four-week follow-up was conducted .
Is Melanotan 2 Safe?
Melanotan II has not been approved for use in humans by the United States Food and Drug Administration (FDA) nor by any of its international regulatory counterparts. Additionally, there is a clear lack of studies into the long-term safety of melanotan II administration.
That said, in published research to date, melanotan II administration has produced minor side effects such as fatigue, nausea, and yawning, and has not been associated with serious adverse events when administered to healthy subjects.
In any event, due caution is required when administering melanotan-II, and it should only be handled by qualified researchers or laboratory professionals.
Melanotan 2 Dosage Calculator
To achieve tanning of the skin, research suggests a melanotan 2 dosage range of 250mcg to 500mcg per day, injected subcutaneously. For testing on a first-time melanotan II subject, it is important to start with the lowest dose possible, before increasing as needed to achieve the desired outcome.
Melanotan II should not be administered indefinitely or continuously, regardless of the research application.
The peptide is commonly administered in conjunction with supplementary tanning sessions. Some researchers suggest that it should only be administered on supplementary tanning session days, and that the melanotan II injection should precede supplementary tanning sessions by about one hour at most.
Where to Buy Melanotan 2 Online
Given the proliferation of contaminated, adulterated, and/or mislabeled peptides, researchers should conduct due diligence before purchasing melanotan II online.
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In our team’s experience, Peptide Sciences sells 99% pure melanotan II and can reliably deliver internationally. This makes them a fantastic choice for researchers looking to work with MT-2.
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Melanotan 2. Just. Works
Melanotan II is known to increase rates of tanning while reducing UV-related skin damage. It has shown promise as a treatment of erectile dysfunction and autism, among other conditions.
Researchers interested in further exploring melanotan II will note that this peptide does not have as favorable a safety profile as melanotan I, as the former has been linked to a greater incidence of side effects in test subjects.
Given the small sample sizes and short durations of the studies on MT-II date, further research into its benefits and side effects is warranted.
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- Mahiques-Santos L. Melanotan [Melanotan]. Actas Dermosifiliogr. 2012 May;103(4):257-9. Spanish. doi: 10.1016/j.ad.2011.08.002. Epub 2011 Nov 1. PMID: 22051769.
- Hadley ME, Dorr RT. Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization. Peptides. 2006 Apr;27(4):921-30. doi: 10.1016/j.peptides.2005.01.029. Epub 2006 Jan 18. PMID: 16412534.
- Dorr RT, Ertl G, Levine N, Brooks C, Bangert JL, Powell MB, Humphrey S, Alberts DS. Effects of a superpotent melanotropic peptide in combination with solar UV radiation on tanning of the skin in human volunteers. Arch Dermatol. 2004 Jul;140(7):827-35. doi: 10.1001/archderm.140.7.827. PMID: 15262693.
- Brennan, R., Wells, J. G., & Van Hout, M. C. (2014). An unhealthy glow? A review of melanotan use and associated clinical outcomes. Performance Enhancement & Health, 3(2), 78–92.
- Dorr RT, Lines R, Levine N, Brooks C, Xiang L, Hruby VJ, Hadley ME. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sci. 1996;58(20):1777-84. doi: 10.1016/0024-3205(96)00160-9. PMID: 8637402.
- Wessells H, Levine N, Hadley ME, Dorr R, Hruby V. Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II. Int J Impot Res. 2000 Oct;12 Suppl 4:S74-9. doi: 10.1038/sj.ijir.3900582. PMID: 11035391.
- Giuliano F, Clément P, Droupy S, Alexandre L, Bernabé J. Melanotan-II: Investigation of the inducer and facilitator effects on penile erection in anaesthetized rat. Neuroscience. 2006;138(1):293-301. doi: 10.1016/j.neuroscience.2005.11.008. Epub 2005 Dec 19. PMID: 16360286.
- Minakova E, Lang J, Medel-Matus JS, Gould GG, Reynolds A, Shin D, Mazarati A, Sankar R. Melanotan-II reverses autistic features in a maternal immune activation mouse model of autism. PLoS One. 2019 Jan 10;14(1):e0210389. doi: 10.1371/journal.pone.0210389. PMID: 30629642; PMCID: PMC6328175.
- Cousen P, Colver G, Helbling I. Eruptive melanocytic naevi following melanotan injection. Br J Dermatol. 2009 Sep;161(3):707-8. doi: 10.1111/j.1365-2133.2009.09362.x. Epub 2009 Jul 2. PMID: 19575725.
- Langan EA, Nie Z, Rhodes LE. Melanotropic peptides: more than just 'Barbie drugs' and 'sun-tan jabs'? Br J Dermatol. 2010 Sep;163(3):451-5. doi: 10.1111/j.1365-2133.2010.09891.x. Epub 2010 Jun 9. PMID: 20545686.
- Evans-Brown M, Dawson RT, Chandler M, McVeigh J. Use of melanotan I and II in the general population. BMJ. 2009 Feb 17;338:b566. doi: 10.1136/bmj.b566. PMID: 19224885.
- Langan EA, Ramlogan D, Jamieson LA, Rhodes LE. Change in moles linked to use of unlicensed "sun tan jab". BMJ. 2009 Jan 27;338:b277. doi: 10.1136/bmj.b277. PMID: 19174439.
- Dreyer BA, Amer T, Fraser M. Melanotan-induced priapism: a hard-earned tan. BMJ Case Rep. 2019 Feb 21;12(2):e227644. doi: 10.1136/bcr-2018-227644. PMID: 30796078; PMCID: PMC6388891.