Melanotan-2

The Melanotan-2 evidence base cited here is 7 sources — 3 clinical, 1 review, 2 regulatory. Its strongest evidence is human — 3 clinical studies, most recently 2009 ("Melanoma Associated with the Use of Melanotan-II"). Regulatory status: Not FDA-approved.

• Melanotan II (MT-II) is a synthetic analog of α-melanocyte-stimulating hormone, developed at the University of Arizona in the 1980s to trigger the body's own tanning response with minimal UV exposure.
• Unlike Melanotan I (which mainly hits MC1R for pigment), MT-II is broad-spectrum — MC1R, MC3R, MC4R, MC5R — which is why it also affects libido and appetite, not just tanning.
• It carries serious, documented safety signals: case reports of melanoma and darkening/eruptive moles during use (with formal MHRA and TGA warnings), plus priapism (erection >4 hrs) as a recognized urological emergency.

Melanotan II is a synthetic cyclic peptide analog of α-MSH that darkens skin, raises libido, and mildly suppresses appetite. It came out of 1980s University of Arizona skin-cancer-prevention research, the idea being to stimulate protective melanin (melanogenesis) without heavy UV exposure.

This is the one monograph where the risks deserve top billing rather than a footnote. MT-II directly stimulates the melanocytes implicated in melanoma, and there are real published case reports — plus formal government warnings — of melanoma and changing moles during use. It also causes priapism, a genuine medical emergency. Its underlying science is legitimate (it spawned an FDA-approved drug), but MT-II itself is unapproved, banned in sport, and unregulated. Everything below is research context, not medical advice — and the safety section matters more here than usual.

MT-II is a small cyclic 7-amino-acid α-MSH analog (~1,024 Da) designed to drive the natural tanning cascade as a photoprotective mechanism against UV-induced DNA damage.

Its key distinction from Melanotan I (afamelanotide): receptor breadth. Melanotan I acts mainly at MC1R (pigmentation), while MT-II binds MC1R, MC3R, MC4R, and MC5R. That wider profile is exactly why its effects spill beyond tanning into sexual function and appetite. (The 'Barbie drug' tabloid nickname is media coinage, not a scientific or regulatory term.)

No FDA-approved dosing exists. The loading/maintenance figures below come from community use, not clinical trials — the only human studies (Dorr 1996, Wessells 1998) used weight-based dosing in small groups. Included for research context only.

• Loading: start ~0.1 mg to assess tolerance, escalate toward ~0.25 mg daily for 2–4 weeks.
• For reference, the Phase I trial tested up to 0.025 mg/kg (~0.2 mg for an 80 kg person).
• Maintenance: ~0.5–1 mg once or twice weekly once desired pigmentation is reached.
• Cycling: some take 4–8 week breaks after 3–6 months for receptor sensitivity (no clinical basis).

MT-II does NOT replace sunscreen or provide full UV protection. Users still need some UV exposure (~10–20 min) for it to tan — it amplifies the response, it doesn't substitute for it.

Subcutaneous injection into abdominal fat, thigh, or deltoid; supplied as lyophilized powder for reconstitution.

• Alcohol-clean the site, pinch a skin fold, insert at 45–90°, inject slowly, withdraw, apply gentle pressure.
• Fine insulin syringes (29–31 g) are standard; rotate sites to avoid lipodystrophy.
• Nasal-spray formulations exist but have lower, less predictable bioavailability and aren't favored by experienced users.

• Week 1: facial flushing, mild nausea, increased libido possible; little visible tan yet; side effects most pronounced now.
• Weeks 2–3: tanning becomes visible with UV exposure; existing freckles/moles may darken quickly; sexual effects well established.
• Weeks 4–6: significant, more even 'golden/bronze' pigmentation; appetite suppression more noticeable.
• Maintenance: tan held with weekly dosing + periodic UV; fades over 1–3 months without maintenance as skin renews.

Response varies with Fitzpatrick skin type, UV frequency, and genetic differences in melanocortin-receptor sensitivity. Rapid mole darkening is also a warning sign — see Side Effects.

MT-II has real but thin human evidence — small early trials and a strong translational legacy, but no modern Phase II/III data for tanning or any indication.

• Phase I (Life Sciences, 1996, Dorr et al.): significant pigmentation increase with minimal UV; dose-dependent tanning, basic safety in a small pilot.
• Erectile function (J Urology, 1998, Wessells et al.): MT-II produced erections in men with psychogenic ED in a double-blind, placebo-controlled crossover — supporting the central mechanism and seeding PT-141's development.
• Receptor pharmacology (Hruby et al.): mapped MT-II's binding across MC receptor subtypes.
• A 2019 Dermatology Online Journal review (Brennan et al.) underscored the gap between preclinical promise and absent Phase II/III data.

The clearest proof its science is real: MT-II research produced bremelanotide (PT-141), which IS FDA-approved. MT-II itself never completed that path.

Combinations aren't validated in research. Research context, not protocol advice.

• MT-II + PT-141 — some alternate MT-II (tanning) with PT-141 (sexual function); do NOT use simultaneously, given overlapping receptor activity. PT-141 has its own FDA-approved, distinct legal/safety profile.
• MT-II + GH secretagogues (Ipamorelin / CJC-1295) — combined for cosmetic/body-comp goals; no established synergy.
• MT-II in cutting phases — used for mild appetite suppression, but its standalone fat-loss contribution is modest and unsupported by dedicated human trials.

• Supplied as sterile lyophilized powder, typically 10 mg vials. Reconstitute with bacteriostatic water added slowly down the vial wall; swirl gently, never shake; solution should be clear and colorless.
• Common ratio: 10 mL BAC water into a 10 mg vial = 1 mg/mL (100 mcg per 0.1 mL / 10 units on an insulin syringe).
• Unreconstituted: refrigerate or freeze, stable 12+ months. Reconstituted: 2–8°C, use within ~4–6 weeks; protect from light; avoid freeze-thaw; discard if cloudy.

MT-II has the most serious risk profile of the cosmetic peptides — two of its concerns are genuinely dangerous, not cosmetic nuisances.

Unregulated sourcing adds purity/sterility risk on top of the compound's own. Given the melanoma signal, anyone using MT-II should have moles monitored by a dermatologist.

• Not FDA-approved for any indication; the FDA has warned about MT-II products sold online over safety, purity, and unsubstantiated claims.
• US: not a controlled substance, but selling it for human consumption violates FDA rules; sold as a 'research chemical' (a label that guarantees nothing about safety/quality).
• Australia: Schedule 4 in theory, but the TGA states it's not approved for any therapeutic use and is a prohibited import.
• UK: not approved; sale for human consumption is illegal under medicines regulations. EU: not authorized, varies by member state.

MT-II is on the WADA Prohibited List under S2 (peptide hormones and releasing factors), banned in- and out-of-competition. It and its metabolites are detectable by standard anti-doping methods, with a window of several days to weeks depending on dosing. Athletes have been sanctioned for it — treat it as a high-risk substance under any WADA-affiliated body.

All citations link to the original source (PubMed, journal site, or regulatory filing). Independent research database — no vendor influence on what's cited.