Melanotan II
MT-II — synthetic alpha-MSH analogue
A synthetic melanocortin analogue that darkens skin, first studied for other indications. It has never been approved, and its effects on pigmented lesions are the central safety worry.
- Category
- Skin & Aesthetics
- Half-life
- Short — on the order of an hour or two in reported pharmacokinetic summaries
- Cycle length
- Not established; studies were short and dose-limited
- Level
- advanced
Overview
Melanotan II is a synthetic analogue of alpha-melanocyte-stimulating hormone that stimulates melanin production, producing tanning without ultraviolet exposure. It was originally investigated as a potential sun-protection and, separately, as a treatment for sexual dysfunction — work that led indirectly to the approved drug bremelanotide. It is one of the most widely used unapproved peptides, and one of the least defensible: it has no approval, its pigmentation effects extend to existing moles, and the dermatological consequences of chronic melanocortin stimulation are unquantified.
How it works
Melanotan II activates melanocortin receptors, principally MC1R on melanocytes, which increases melanin synthesis and transfers pigment to surrounding skin cells. Broad receptor activity also engages MC3R and MC4R, which is why it produces effects beyond the skin: nausea from MC4R activation, flushing, and increased sexual arousal in both men and women.
Reported benefits
- Increased melanin production and darker skin in clinical studies of the analogue
- Reduced ultraviolet-induced skin damage in some experimental work
- Effects on sexual arousal that led to a separate approved medicine
- No ultraviolet exposure required for the pigmentation effect
Reported benefits describe what the published literature and user reports suggest — not a promise of outcome for any individual.
Dosing reference
Early academic studies used approximately 0.025 mg/kg by subcutaneous injection, with further doses adjusted to response. No approved product or approved dose exists, and community protocols often escalate well beyond the studied range.
The studied dose range came from short, closely observed trials. Escalating beyond it increases the intensity of nausea and cardiovascular effects without any evidence of benefit, and it is usually the pattern in which problems arise.
Community-reported: 250–500 mcg daily during a loading phase, then a maintenance dose every few days. Amounts above 1 mg are widely described as producing severe nausea and prolonged erections.
These figures are what people report using in public communities. They have not been studied, verified or checked against certificates of analysis, and they are not a recommendation, a prescription or a target to aim for.
Where the reported amounts come from
Amounts are reproduced for education only. Doses from trials cannot be assumed to suit anyone else, and community-reported amounts are frequently wrong. Self-administering unapproved compounds carries serious risk.
The research picture
Clinical work on melanotan II dates to small studies in the 1990s that demonstrated melanin increase and, in a separate line of research, effects on sexual arousal. Neither indication led to approval for this compound. The related metabolite became bremelanotide, which is approved for a specific sexual-dysfunction indication and is given under medical supervision. Dermatological concerns dominate the risk discussion: users report darkening of existing moles and new pigmented lesions, and there is no long-term study examining whether chronic melanocortin-driven pigmentation alters melanoma risk. Regulators have repeatedly warned about unapproved tanning peptides sold online, which are also frequently mislabelled or contaminated.
Preclinical & non-clinical data
A melanocortin receptor agonist; the tanning effect follows directly from the pharmacology and has been shown in animal and small human studies. Regulators including the US FDA have issued warnings, and there is no approved human product.
Non-clinical data comes from cells and animals unless stated otherwise. It answers whether a compound is worth studying in people — not whether it is safe or effective in them.
What users report
The reporting is candid in a way that rarely helps the compound's case. Users describe nausea, flushing and appetite loss in the hours after a dose, darkened moles and new freckles appearing over a course, and the tanning effect they were after. Priapism — a medical emergency — is described both in the published literature and in forum accounts, and the mood and libido effects users chase are the same pathway that produces it. Several accounts also describe stopping because their moles kept changing.
Where these reports come from
These are unverified personal accounts collected from public sources. They are not evidence of effectiveness or safety, they have not been independently checked, and they are not a recommendation to use anything described.
Possible side effects
- Nausea, often severe shortly after dosing
- Facial flushing and warmth
- Spontaneous erections
- Darkening of existing moles and new pigmented lesions
- Fatigue and yawning
- Blood-pressure changes
Safety notes
Not approved anywhere. The main documented concern is pigmented lesion change, which means anyone with a personal or family history of melanoma, atypical moles, or significant sun damage should avoid it outright. Nausea and cardiovascular effects occur even at studied doses. Unregulated supply has been repeatedly found to contain the wrong compound or the wrong amount, which for a peptide with a narrow tolerated range is a serious problem.
Stacking
Sometimes combined with tanning-bed use, which adds ultraviolet exposure to a compound already driving pigmentation — the opposite of risk reduction. There is no evidence for combining it with anything.
Related compounds
GHK-Cu
Copper tripeptide-1
Skin & Aesthetics
A copper-binding tripeptide with a long cosmetic history.