The melanocortin peptide used for sunless tanning and libido enhancement — powerful results, but a side-effect profile that demands careful titration.
Melanotan II (MT-II) is a synthetic analog of alpha-melanocyte-stimulating hormone (α-MSH) that non-selectively activates multiple melanocortin receptors — MC1R (pigmentation), MC3R/MC4R (appetite, libido), and MC5R (exocrine).
Originally developed at the University of Arizona to help reduce skin cancer risk by inducing protective pigmentation without UV exposure. It never completed clinical development but became popular as a tanning peptide, with PT-141 (bremelanotide) being a selective MC4R derivative that was eventually approved as Vyleesi.
Not FDA approved. Not WADA prohibited. Banned in several countries; available as research chemical elsewhere.
Activates melanocytes to produce eumelanin (brown/black pigment), darkening skin over 2–4 weeks of regular dosing. Important: UV exposure is still required to trigger the pigmentation response — MT-II amplifies your tan, it doesn’t replace sun/UV entirely.
Same mechanism as PT-141 — suppresses appetite and increases sexual desire/arousal via central nervous system pathways.
Non-selective activation of these receptors accounts for most of the side effect profile (nausea, flushing, darkening of moles and freckles).
| Benefit | Evidence |
|---|---|
| Skin pigmentation | Arizona studies: reliable induction of eumelanin production; dramatic darkening with continued use + UV exposure |
| Libido / sexual arousal | Same MC4R mechanism as PT-141; both male and female effects |
| Appetite suppression | Noticeable reduction in hunger; sometimes used adjunctively for weight loss |
| UV damage reduction | Induced pigmentation offers some photoprotection (but doesn’t replace sunscreen) |
MT-II is the less-selective parent of PT-141. If you want the libido effect without pigmentation changes, PT-141 is the cleaner option.
Build your protocol, log every dose, monitor your body's response, and get reminders so you never miss a dose.
Start Tracking FreeDo not skip the starter dose. First-time nausea can be intense.
10 mg vial + 2 mL BAC water = 5 mg/mL = 5000 mcg/mL
| Dose | Volume | Syringe Units |
|---|---|---|
| 250 mcg (starter) | 0.05 mL | 5 units |
| 500 mcg | 0.10 mL | 10 units |
| 1 mg | 0.20 mL | 20 units |
10 mg vial at 1 mg/day = 10 days; at 1 mg 2×/week maintenance = 5 weeks
Pre-filled with a typical Melanotan II setup. Edit any field — the draw updates live.
Insulin syringe — 100 units = 1 mL
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MT-II has a notable side-effect profile — often the reason users switch to the more selective PT-141 for libido-only goals.
Case reports document rhabdomyolysis, acute kidney injury, and renal infarction following MT-II use — particularly at high doses. One case (PMID 23121206) reported a single 6 mg SubQ dose producing BP 151/85, HR 146, and rhabdomyolysis. A separate case series (PMID 31953620) documented thrombotic/renal complications.
Doses above the recommended range can trigger severe sympathomimetic toxicity — tachycardia, hypertension, and muscle breakdown. Do not chase faster results with larger doses. If you experience dark urine, severe muscle pain, chest pain, or a racing heart, seek emergency care.
Any new mole, changing mole, or mole with irregular borders while on MT-II warrants immediate dermatologist evaluation. Several case reports link MT-II use to melanoma progression.
MT-II is unregulated and almost exclusively purchased through grey-market online channels (PMID 30142729). Counterfeit and falsified biotechnology peptide drugs are a documented global safety threat (PMID 30165334) — contamination, incorrect potency, and substitution with other compounds are all real risks. Product purity cannot be verified without third-party testing; buy only from suppliers that publish current certificates of analysis, and accept that all use is at your own risk.
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Build your protocol, log every dose, monitor your body's response, and get reminders so you never miss a dose.
Start Tracking FreeNo. Melanotan II (MT-II) has never been approved by the FDA or any Western regulatory authority and is sold by underground vendors as a research chemical. Important distinction: a related molecule, Melanotan I (afamelanotide, brand name Scenesse), IS FDA and EMA approved — but for erythropoietic protoporphyria, a rare blood disorder, NOT for cosmetic tanning. The UK MHRA, Australian TGA, and other regulators have issued explicit consumer warnings against MT-II.
No. They are chemically related but different agents with different regulatory status, receptor selectivity, and evidence bases. MT-II is non-selective across MC1R/MC3R/MC4R/MC5R receptors. PT-141 (bremelanotide, Vyleesi) is a MC4R-preferring derivative of MT-II that is FDA approved for HSDD in premenopausal women. MT-II is not bremelanotide, and the "PT-141 was developed from MT-II research" framing should not be misread as "they are the same drug."
Community-practice dosing: a loading phase of 250–500 mcg per day subcutaneously for the first 1–2 weeks (until visible pigmentation), then a maintenance phase of 250–500 mcg 2–3 times per week. There is no controlled dose-finding data — these figures come from community convention. Doses sit far below afamelanotide (Scenesse) which is implanted at 16 mg per implant every 2 months in EPP patients.
A typical reconstitution is 10 mg of MT-II + 2 mL of bacteriostatic water, yielding 5 mg/mL. A 250 mcg dose draws to 0.05 mL (5 units on a 100-unit insulin syringe), 500 mcg = 0.10 mL (10 units). Most users inject in the abdomen 30–60 minutes before brief sun or red-light exposure.
Common: nausea (especially with the first few doses, often pronounced — sometimes requiring antiemetic), flushing, spontaneous erections in men (Dorr 1996 PMID 8637402 documented this), appetite suppression, and yawning. Important cosmetic concern: MT-II also stimulates EXISTING melanocytic lesions — moles can darken, grow, or even appear. Schulze 2014 (PMID 24334249) documented eruptive nevi and pre-existing nevus darkening within 24 hours of a single MT-II dose. People with a personal or family history of melanoma should not use MT-II.
Eumelanin upregulation provides some photoprotective benefit in principle, but the magnitude at community MT-II doses has not been formally quantified in peer-reviewed literature. Photoprotection data at regulatory-grade quality exists for afamelanotide (Scenesse, MT-1) in EPP patients — NOT for MT-II in cosmetic users. Treat any "photoprotective" claim about MT-II as inference from mechanism, not from data.
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