Melanotan II
Also called MT-2, MT2, melanotan 2
Melanotan II is the "tan without the sun" peptide.
Studied in people, in small numbers. The ranges below lean mostly on community-reported dosing and results — what people run, and what they say happened.
- Sexual health
- Skin & hair
- Tanning
The quick answer
Melanotan II is the "tan without the sun" peptide. It switches on the cells that make melanin, so your skin develops real colour with far less UV exposure than natural tanning would need - and because it also touches a second receptor, most people notice a libido bump along the way.
Colour usually starts showing after about five doses and holds for weeks after you stop, which is what the lighter maintenance schedule keeps up. Early on, expect some day-one nausea, flushing, and yawning that fade as your body adjusts. Be honest with yourself here: it's unregulated, and because it can darken moles, keep a close eye on your skin and start at the low end.
Why people use it
☀️ A deep tan with barely any sun; ⏳ Colour that lasts; 🔥 Libido and arousal boost; 🍽️ Mild appetite reduction; 🎨 Works on all skin types
What people report using
These are ranges other people have reported running. They are here so you can see what has actually been done — they are not medical advice and not a recommendation for you.
- How often
- Every evening
- Route
- subcutaneous
- Evidence for this
- Small human studies
Colour develops over a couple of weeks and keeps developing after you stop, which is why people overshoot.
10mg vial + 2ml BAC water = 5mg/ml. Start 0.25mg (5u) for 3-5 days, then 0.5mg (10u). Evening.
Work out your own units on the reconstitution calculator — the most common serious mistake in this area is arithmetic, not chemistry.
What to expect, and when
- First thing people notice
- Days 3–5 (libido, appetite)
- When it gets real
- Weeks 1–3 (tanning begins)
- Where it peaks
- Weeks 3–6 (full tan)
- Patience needed
- Low - fast on libido/tan
- Days 1–3Nausea window (start at 0.25mg - not 0.5mg)
The first 3–5 days are about tolerance. Start at 0.25mg (0.05ml · 5 units), evening injection. Nausea is common and fades as the body adapts. Evening injection lets you sleep through it. Do not rush to the full 0.5mg loading dose - the tolerance build matters here.
- Days 3–7Libido & appetite changes noticeable (MC4R activation)
MC4R receptor activation in the brain produces libido changes and appetite suppression relatively quickly - often felt within the first week. Food becomes less appealing. Spontaneous desire increases. These effects often precede the visible tanning by 1–2 weeks.
- Weeks 1–3Tanning begins with UV exposure (MC1R activation)
Melanin production increases via MC1R. The tan develops significantly faster than normal with sun exposure - even 15–20 minutes produces noticeable colour. Without any UV exposure the colour won't develop, but the melanocytes are primed and ready. Some get "facial flushing" freckle darkening first.
- Weeks 3–6Full tan & body composition effects peak
Tanning reaches full depth. Body composition changes become visible as appetite suppression compounds - users commonly report unintentional fat loss without conscious restriction. Muscle definition often improves alongside the tan. Maintenance dose (2–3×/week) can sustain these effects ongoing.
Monitor all moles throughout the MT-2 cycle. Increased melanin production applies to all melanocytes - including those in existing moles. Photograph moles at the start of the protocol and check for changes monthly. Any new moles or changes in existing ones warrant dermatology consultation.
Side effects, and what people do about them
Most people tan well on this without much fuss. Some nausea or a flushed feeling in the first hour is common early on and usually fades, and starting low makes the whole thing smoother.
The one thing to take seriously is your skin. This deepens pigment everywhere, including in moles - new moles and darkening of existing ones have been reported, in one case within a day of a single injection, and there are a small number of published melanoma cases in people who used it. Get a skin check before you start and keep an eye on anything that changes.
Please do not use this at all if you have a personal or family history of melanoma, a lot of moles or atypical ones, very fair skin that never tans, or any mole that has changed recently. And do not stack it with sunbeds.
If what you are actually after is the libido effect rather than the tan, PT-141 is the better answer - it is the same mechanism, it went through full approval, and it does not build pigment.
Go deeper
Open these only if you want them.
How it actually works
Cyclic analogue of alpha-MSH and a non-selective melanocortin agonist - it binds MC1R, which controls pigment, along with MC3R and MC4R, which sit in appetite and sexual-arousal pathways, and MC5R. The non-selectivity is not a flaw in manufacture; it is what the molecule is, and it explains why the effects people are not looking for arrive alongside the ones they are.
For stacking, the specific thing to know is that PT-141 is a metabolite of this compound and is MC4R-selective. Running both is stacking the same receptor by two routes - you get more of the same effect and more of the same cost, not a broader one.
What people report, in full
For tanning, Melanotan II is one of the most reliable peptides out there - around nine in ten report real, deep colour, usually visible within 5–7 days and fully developed by weeks two to four. Many also mention a libido and arousal boost as a side effect. The trade-off, which is nearly universal in the first few weeks, is loading-phase nausea, flushing and yawning - uncomfortable but temporary. The community's standing advice is to stay disciplined with daily dosing during loading, start low, and keep a close watch on your skin and moles.
Sources and review
https://pubmed.ncbi.nlm.nih.gov/9679884/
https://pubmed.ncbi.nlm.nih.gov/19575725/
Last reviewed 2026-09-06.
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