Melanotan is a synthetic chemical that mimics a hormone found within the body known as melanocyte-stimulating hormone. It was created originally to treat certain skin conditions, but now is available on the internet as a supplement. It is primarily used for skin tanning, however, it has also been used for conditions like erectile dysfunction, rosacea, and others (1).
Melanotan works by mimicking melanocyte-stimulating hormone. In particular, melanotan II is a non-selective melanocortin-receptor agonist and an alpha-melanocyte stimulating hormone (2). Melanocyte-stimulating hormone is responsible for increasing the skin’s production of darkening pigments. That is why melanotan is commonly used for the purposes of skin tanning.
Melanotan may also have activity in the brain, specifically with regards to stimulating penile erections, hence its use in erectile dysfunction (1).
There is some limited research showing that melanotan II may have effects in treating erectile dysfunction. In a double-blind, placebo controlled crossover study, ten men with erectile dysfunction were treated with melanotan II. Findings showed that eight out of the ten men that were treated with melanotan II experienced clinically apparent erections (3). Another study in 20 men with erectile dysfunction indicated that 17 who were treated with melanotan II were able to experience penile erection in the absence of sexual stimulation (4).
With regards to tanning effects, a human study in 1996 showed that subcutaneous injections of melanotain II for two weeks induced increased pigmentation with UV exposure. However, individuals experienced side effects even at low doses (5).
There is evidence that melanotan II can increase melanin production and induce erections by way of the melanocortin pathways. However, the safety of its long-term use is not well-characterized, and there may be significant safety concerns.
Melanotan II is not approve day the US Food and Drug Administration (FDA) and its use is considered illegal. Its development in humans has likely not continued due to the side effect profile as well as its widespread effects on hormone levels.
As it is not approved by the FDA, melanotan is not regulated for its quality. Therefore, any formulations obtained online carry concerns related to purity, contamination, and mislabeling.
In the clinical study in patients with erectile dysfunction, melanotan II induced side effects of lower appetite, nausea, yawning, and stretching after receipt of injections (3). Additionally, there have been case reports of individuals suffering from acute priapism after receiving abdominal injections of melanotan. Priapism is defined as a persistent and typically painful erection that continues for greater than four hours (6).
The research shows that melanotan II is a biologically active substance, as evidenced by studies in humans for indications such as tanning and sexual function. However, it is associated with several safety risks and side effects as well as concerns related to its unregulated use.
The information provided in this article is for educational purposes only and is not intended as medical advice. Many peptides are not FDA-approved for human use outside of limited clinical contexts. These compounds are often obtained through unregulated sources that lack quality control. Studies suggest 30–65% of products may be contaminated or mislabeled, with risks including endotoxins, heavy metals, and incorrect sequences. At Weight Loss & Vitality, we focus on evidence-based, medically supervised therapies.
As of April 21, 2026, regulatory status for many peptides remains under review and may change as additional data and guidance become available.
Peptides offer exciting potential, but they require a structured and cautious approach. Our personalized peptide therapy services focus on achieving optimal outcomes while minimizing unnecessary risk.
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