Melanotan-2
Also known as: MT-2
The unregulated tanning peptide. Cheaper and more effective on libido than MT-1, but the side effect profile and mole-change risk make this the riskier of the two.
Overview
Melanotan-2 is a non-selective melanocortin agonist. It hits MC1R for pigmentation, MC4R for libido and appetite suppression, and MC3R for thermal regulation. The broader receptor profile is why MT-2 has a busier side-effect column than MT-1, and the off-label reputation as a 'tan plus libido' peptide. It also produces the side effect MT-1 doesn't: spontaneous erections in men, and a real if uncommon priapism risk that has put people in the ER. The melanoma concern is the larger long-term issue. MT-2 is not approved anywhere; everything comes from twenty years of European recreational use and a small number of case reports, mostly about adverse events.[1]
Evidence quality
No completed Phase 3 trials. Melanotan-2 was studied in the 1990s as an erectile dysfunction candidate before being abandoned in favour of bremelanotide (PT-141), which has cleaner pharmacology. All current use is grey-market and unregulated. Case reports in dermatology journals document melanoma in MT-2 users; the relationship is concerning but not formally proven.
Benefits & timeline
Benefits
- Reliable tanning, often faster onset than MT-1 because the dose schedule is more aggressive
- Libido increase in both sexes — a centrally mediated effect, similar mechanism to PT-141
- Appetite suppression — modest, but consistent
- Cheap and widely available on the grey market
Timeline
Week 1
Pigment darkening starts; libido increase often noticeable within the first few doses.
Week 2
Visible tan; nausea usually settles.
Week 4
Pigmentation plateau; loading dose ends.
Week 6+
Maintenance at lower frequency holds the colour.
After stopping
Pigment fades over 1–3 months; moles often remain darker.
Dosage protocols
Advanced
1 mg
every other day, then weekly maintenance
Beginner
250 mcg
daily for 7 days
Standard
500 mcg
daily for 10 days
Titration & adjustment
Loading: start at 250 mcg daily for the first week (lower than MT-1 because of the broader receptor profile). Escalate to 500 mcg daily for week 2 only if nausea is tolerable. Drop to maintenance of 500–1000 mcg twice weekly once your target tan is reached. Do NOT dose daily long-term — the spontaneous-erection side effect persists.
Injection timing
Same as MT-1 timing for tanning. For the libido side effect, dose 1–2 hours before desired activity. Avoid bedtime dosing — the spontaneous-erection side effect can disrupt sleep.
Side effects & contraindications
- moderateNausea, sometimes severe, especially in the first week. Worse than MT-1.
- moderateSpontaneous erections — uncomfortable, predictable, and at the higher end can become priapism (sustained erection over 4 hours), which is a urological emergency.
- moderateMole darkening and new naevi formation, with case reports of melanoma emerging in pre-existing moles during MT-2 use. Causation is debated; the temporal correlation is documented.
- mildAppetite suppression — usually welcome, occasionally to a worrying degree.
- moderateNo long-term human safety data; the grey-market track record is long but not systematically monitored.
Contraindications
- Any history of melanoma or many atypical naevi — the mole signal is too high a risk against a cosmetic benefit
- Sickle cell disease or other conditions predisposing to priapism
- Pregnancy or breastfeeding
- Concurrent use of erectogenic drugs (sildenafil, tadalafil) — additive priapism risk
- Children, adolescents, and anyone whose skin hasn't been surveyed by a dermatologist recently
Reconstitution & injection
A 10 mg vial reconstituted with 2 ml bacteriostatic water gives 5 mg/ml. A 500 mcg dose is 0.1 ml, which is 10 units on a U-100 insulin syringe. Subcutaneous in the abdomen. Start at 250 mcg to gauge nausea; 500 mcg is the standard loading dose only when the lower dose has been tolerated. Avoid bedtime dosing — the erection side effect can wake you up.
Open calculator pre-filledStorage after reconstitution
Refrigerate at 2–8 °C after reconstitution. Do not freeze. Light-protected. 30 days of stability at fridge temperature. Same photosensitivity caution as MT-1 — wrap the vial or store in an opaque bag. A vial left on a sunny windowsill for even one afternoon will degrade noticeably.
Cost & sourcing red flags
Typical price range: 10 mg vials from research-grade peptide vendors: $15–40 per vial. A full tan-induction protocol (5–10 mg total over 3–4 weeks) costs under $50 in raw peptide. This is one of the cheapest peptides on the grey market, which is itself a sourcing problem.
Red flags
- 10 mg vials under $10. MT-2 is so cheap that the floor for genuine product is around $12–15; bargain-bin pricing reliably correlates with underdosed or contaminated vials.
- Vendors selling MT-2 in bulk powder by the gram for buyer-reconstitution. Without bacteriostatic-quality control and weighing precision better than 1 mg, home-reconstituted MT-2 routinely overdoses by 2–4x the intended amount, which is the leading cause of severe-nausea reports.
- No mention of impurities or batch testing for related peptides. Crude MT-2 synthesis can leave residual MT-1 and truncated sequences; cheap vendors do not separate them.
- Tanning-salon resellers handing out pre-reconstituted MT-2 syringes. Once mixed in bacteriostatic water, MT-2 has a 30–60 day cold-chain shelf life, and salon storage conditions rarely meet that.
- Vendors marketing MT-2 with claims of 'safe for women' or 'no mole darkening at low dose'. Mole darkening is a melanocortin-1 receptor effect and happens at any dose that produces visible tan; the claim is false.
Pricing rots fast and varies by region and supplier. We list no vendors.
Common mistakes
Treating it as a 'better MT-1'.
Better approach: It isn't better; it's broader. The extra receptor activation buys you libido and appetite effects, but it also buys you the priapism, nausea, and mole-change risk. If pigment is your only goal, MT-1 is the cleaner pick.
Skipping the dermatology baseline.
Better approach: Get every mole photographed before you start. The peptide will darken them; you need a reference set so that when one changes shape or grows asymmetrically, the dermatologist has something to compare against.
Running it long-term as a chronic libido aid.
Better approach: The libido effect tolerates with chronic dosing and the priapism risk doesn't. PT-141 on demand is the cleaner tool for libido; MT-2 is for cosmetic tanning with libido as a side perk, not the other way around.
Doubling the dose to hit a darker tan faster.
Better approach: Pigmentation has a ceiling; nausea and side effects don't. Higher doses just produce more side effects without measurably more colour. Stay at 500 mcg per dose; if the tan isn't deep enough, extend the loading window, not the per-dose amount.
Real-world tips
- Inject in the morning, never close to bedtime. Erections at 2 AM are exactly as unpleasant as they sound, especially after the third one.
- Have a urology number on hand — priapism over 4 hours is an emergency, and treating it within the first 6 hours preserves erectile function long-term.
- Photographic mole tracking, monthly. Any mole that grows, changes border, changes colour, or itches gets reviewed by a dermatologist.
- Refrigerate the reconstituted vial. Stability beyond 4–6 weeks is dubious.
- Be honest with yourself about the cosmetic-versus-risk math. Self-tanner reaches the same end state visually with none of the systemic risk.
What users report
Aggregated from r/Tanning, r/Melanotan, and r/Peptides threads. Not clinical data.
Onset: Subcutaneous 0.25–0.5 mg daily titration: first faint pigmentation change at 7–10 days, visible tan at 2–3 weeks with UV exposure, full bronze at 5–8 weeks.
Common reports
- Nausea in the 30–90 minute window after dosing is near-universal at 1 mg and above; the standing protocol on forums is 'start at 0.25 mg, hold there for a week, then move up by 0.1 mg at a time'.
- Spontaneous erections in men within 2–4 hours of dose, often more frequent than the user wants, particularly in the first 2 weeks before tolerance builds.
- Appetite suppression is the other commonly mentioned secondary effect; users report eating noticeably less for the first 2 weeks of a cycle.
- Existing moles darken substantially and new freckles appear within 3–6 weeks; this is the most cited reason users stop and the source of the persistent 'get a dermatology baseline first' advice.
- Dose-stop pattern: a large fraction of forum users complete only one tanning-induction cycle (2–4 weeks) and never restart, citing nausea, mole anxiety, or 'tan held for months anyway'.
Where reports diverge from theory: Mechanistic literature treats MT-2 as a melanocortin-1/4 agonist with predictable tanning. The forum reality has two divergences. First, the pigment effect on existing moles is more dramatic than the published literature implies, because the literature is dominated by short trials in light-skinned EPP cohorts, not 6-month recreational use. Second, the cardiovascular effects (elevated resting BP, tachycardia) reported in research doses are largely absent or unnoticed in self-reports, which probably reflects that home users rarely measure either and not that the effect is absent.
When something else is the better tool
Melanotan-1
Use instead when: Tanning alone is the goal and you want the cleaner side-effect profile. Same pigment effect, no libido side effects, no priapism risk.
PT-141
Use instead when: Libido is what you actually want and tanning is incidental. PT-141 is the more refined libido tool, with a real regulatory approval behind it.
DHA self-tanner
Use instead when: You're talking yourself into this peptide purely for the look. The cosmetic outcome is similar at a distance, with zero systemic exposure and no mole concern.
Based on 1 peer-reviewed study
- Why does it cause erections?
- MT-2 activates MC4R in the central nervous system, which drives sexual desire and erection. Same mechanism PT-141 uses, but MT-2 isn't selective so you also get MC1R (tanning) and MC3R effects.
- Is the melanoma risk real?
- Case reports document melanoma developing in pre-existing moles during MT-2 use. Biological plausibility (melanocyte stimulation) exists. Formal causation hasn't been established and won't be — no large prospective trials. Treat as a risk the absence of proof doesn't disprove.
- Will the pigment last?
- Months, but fades. Melanin-laden cells turn over with normal skin renewal. Most people see noticeable fade by 8–12 weeks off.
- Can women use it?
- Yes. Libido effect is present in both sexes. Mole concern is the same. Pigment effect works identically.
- How is this different from PT-141?
- PT-141 is selective for the libido side of the melanocortin family and is approved for HSDD. MT-2 hits the libido receptors plus tanning plus appetite, with a much broader side-effect signature.
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