Melanotan II
Also known as: melanotan 2, mt-2, mt2, MT-II
Non-selective melanocortin receptor agonist studied for tanning, libido, and appetite suppression.
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Overview
Drug that never made it to the market
Melanotan II is a synthetic analogue of the peptide hormone α-melanocyte-stimulating hormone (α-MSH) that stimulates melanogenesis to facilitate tanning. It may also increase sexual arousal. Melanotan II was originally developed as a tanning agent based on an earlier drug called afamelanotide, which is now approved by the FDA for the treatment of a particular rare genetic form of sun sensitivity. Melanotan II was later investigated as a potential treatment for sexual dysfunction, but development was abandoned in 2000 in order to pursue development of bremelanotide, a chemically similar drug later approved by the FDA for treatment of sexual dysfunction in women. Unlicensed melanotan II is found on the internet, although health agencies advise against its use due to legality, case reports suggesting significant safety risks, and potential impurities.
Mechanism of Action
Non-selective melanocortin receptor agonist (MC1R–MC5R), stimulates skin pigmentation and activates sexual arousal pathways.
What is Melanotan II?
Melanotan II is a lab-made cyclic peptide that activates melanocortin receptors, the same receptor family involved in skin pigmentation and other signaling. In early clinical studies, researchers observed increased skin darkening, and separate human studies noted effects on sexual arousal pathways, which later led to an approved derivative drug. It is not FDA approved.
How It Works - Simply Explained
Melanotan II locks onto several melanocortin receptors (MC1R, MC3R, and MC4R). MC1R signaling is tied to melanin production in skin cells, which is why tanning effects were observed in studies. MC4R signaling connects to brain pathways involved in sexual function, which is why researchers studying those pathways took interest. A trimmed-down derivative of this molecule, bremelanotide, eventually earned FDA approval for a specific indication.
What Studies Have Found
Pilot human trial: tanning without the sun
In an early phase 1 pilot study, researchers reported that melanotan II induced measurable skin darkening in human volunteers. The study was small and exploratory, but it was the first human evidence that a melanocortin peptide could drive pigmentation directly. The authors also noted side effects including nausea and flushing.
Dorr et al., 1996, Life Sciences
Unexpected finding: effects on erectile function
During human studies, researchers observed that melanotan II produced erectile responses in male volunteers, an effect traced to MC4R signaling in the central nervous system rather than any vascular action. This surprise finding redirected an entire line of research and was published in urology literature.
Wessells et al., 2000, Journal of Urology
The pathway gets mapped: melanocortins and sexual function
A later review pulled the evidence together, detailing how melanocortin receptor activation influences sexual behavior pathways in animal and human studies. The review helped explain why the MC4R receptor became a drug target and set the stage for derivative compounds designed to keep the desired signaling while shedding side effects.
King et al., 2007, Current Topics in Medicinal Chemistry
From research peptide to approved drug: the bremelanotide story
Scientists re-engineered the melanotan II scaffold into bremelanotide, a more selective MC4R agonist. After clinical trials, bremelanotide was FDA approved for hypoactive sexual desire disorder. It is a rare example of a research peptide in this family completing the full journey from laboratory curiosity to approved medicine.
Bremelanotide clinical development literature, FDA approval records 2019
Last updated 2026-10-06. New findings are added as published research appears.
Frequently Asked Questions
What is Melanotan II?
Melanotan II is a synthetic cyclic peptide that activates melanocortin receptors. It was studied in early human trials for skin pigmentation, where researchers observed tanning effects, and separately for its effects on sexual function pathways. It is for laboratory research only and is not FDA approved.
Is Melanotan II FDA approved?
No. Melanotan II itself has never been FDA approved. However, a derivative compound called bremelanotide, developed from the same melanocortin research, did receive FDA approval for hypoactive sexual desire disorder.
What did the tanning studies find?
In a small phase 1 pilot study, researchers reported that melanotan II produced measurable skin darkening in volunteers. The study also documented side effects such as nausea and flushing. These were early exploratory findings, not proof of safety or efficacy.
What is the connection to bremelanotide?
Bremelanotide was engineered from the melanotan II scaffold to target the MC4R receptor more selectively. It went through full clinical trials and earned FDA approval, while melanotan II itself remained a research compound.
What side effects were reported in studies?
Published studies reported nausea, flushing, and appetite changes among the observed effects. Because the compound acts on multiple receptor types, researchers noted a broad side effect profile, which is one reason drug developers pursued more selective derivatives.
How is Melanotan II different from Melanotan I?
Both are melanocortin peptides studied for pigmentation, but Melanotan II is a shorter cyclic molecule that acts on a broader set of melanocortin receptors, including those linked to sexual function pathways. Melanotan I (afamelanotide) followed a different development path.
Can I use Melanotan II personally?
No. Melanotan II from research suppliers is for laboratory research only. It is not for human consumption, has not been evaluated by the FDA, and is not a medicine. This page describes published research only.
What Researchers Are Saying
Community Reports - Not Medical Advice
The following is aggregated from public forums, Reddit, and research communities. These are anecdotal reports from researchers only - not verified clinical data and not a recommendation of any kind.
Melanotan II (also known as melanotan 2, mt-2) is studied within the sexual health and hormonal research community. Non-selective melanocortin receptor agonist studied for tanning, libido, and appetite suppression.
Last updated October 28, 2026
Research status: active. Melanotan II appears across sexual health and hormonal research forums and academic literature. Researchers note this compound falls in the sexual health category.
Last updated October 28, 2026
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