The short version.
If you read nothing else, read this. The whole guide in a handful of bullets.
- What it is: Melanotan II is a synthetic copy of alpha-MSH, a natural hormone that controls skin pigment. It is the lab-made version that switches on the same melanocortin receptors.
- What people run it for: deeper, longer-lasting tanning with much less sun, and a strong boost in libido and arousal that many notice as a side effect.
- Typical dose: about 250mcg once daily during a short loading phase, then 250mcg to 500mcg once or twice a week to maintain.
- Routes: subcutaneous injection is the standard. It is not a meaningful oral peptide.
- Cycle: a loading phase of two to three weeks to build the tan, then a lower weekly maintenance dose, run in cycles rather than continuously.
- Honest caveat: the human evidence is thin and mostly from small early trials and community reports. It is sold for research use only, carries real safety concerns like darkening moles, and this is not medical advice.
Quick reference.
| Typical dose | 250mcg daily loading, then 250-500mcg 1-2x/week |
|---|---|
| Routes | Subcutaneous injection (standard only) |
| Frequency | Daily during loading, then once or twice a week |
| Cycle length | 2-3 week loading phase, then maintenance, in cycles |
| Best for | Tanning with less sun, plus a noticeable libido boost |
What is Melanotan II?
Melanotan II is a short peptide, which simply means a small chain of amino acids, the same building blocks that make up the proteins in your body. It is a synthetic copy of a natural hormone called alpha-melanocyte-stimulating hormone, or alpha-MSH, which your body already produces.
Alpha-MSH tells the pigment cells in your skin to make more melanin, the brown pigment that gives you a tan. Researchers built Melanotan II to be a stronger, longer-lasting version of that signal, originally hoping it could protect fair-skinned people from sun damage by letting them tan with far less UV exposure.
The version sold by vendors arrives as a freeze-dried white powder in a small sealed vial. It is not a steroid, not a stimulant. What surprised the original researchers is that it does two things at once: it tans the skin, and it acts on arousal pathways in the brain. That second effect was strong enough that scientists spun off a separate peptide, PT-141, to chase it on purpose.
Worth saying plainly: Melanotan II is not an approved medicine anywhere. It is sold strictly for research use only, the human evidence is thin, and it carries real safety concerns, including darkening moles and new ones. We get into what that means further down.
How it works in the body.
You do not need a biology degree to follow this. Here is the simple picture, then a little more for the curious.
The core idea is that Melanotan II copies a natural hormone and switches on a family of receptors called the melanocortin receptors. These sit in different places in the body, which is why one peptide produces effects as different as a tan and a libido boost.
- Pigment (MC1 receptor). In the skin, Melanotan II activates the MC1 receptor on your melanocytes, the pigment cells. That pushes them to make more melanin, so you tan faster and darker with less sun.
- Arousal (MC3 and MC4 receptors). In the brain, it acts on the MC3 and MC4 receptors, which are tied to sexual arousal. This is the libido effect people notice, and the reason PT-141 was later built to target these receptors more cleanly.
- Appetite and other effects (MC4 and beyond). The same MC4 receptor is involved in appetite, which is why some people report eating less. Because Melanotan II hits all five melanocortin receptors, its effects are broad rather than targeted.
How to take it: routes of administration.
Melanotan II is an injectable peptide. It is not a meaningful oral or nasal option, so in practice the only route is subcutaneous injection. Here is the honest comparison.
| Route | Typical dose | Absorption | Best for | Difficulty |
|---|---|---|---|---|
| Subcutaneous | 250mcg | Reliable, systemic | Tanning and libido | Tiny needle, easy to learn |
| Intramuscular | 250mcg | High | Not necessary | More invasive, rarely used |
| Oral | Not practical | Very low | Not recommended | Poorly absorbed |
Subcutaneous injection
The standard route by far. A tiny insulin needle goes into the fat just under the skin, not into muscle. Because Melanotan II acts body-wide through the bloodstream, a simple subcutaneous shot into the belly works well, and it is far less intimidating than it sounds.
Intramuscular
There is no real reason to inject Melanotan II into muscle. The doses are tiny and it works fine subcutaneously, so an intramuscular shot just adds discomfort for no benefit. Almost nobody runs it this way.
Oral
Melanotan II is not a practical oral peptide. It does not survive digestion well, so capsule versions are not worth chasing. Stick to the injectable form.
Where to inject.
If you go this route, these are the sites people use. Rotate so no single area gets sore.
The easiest spots are the belly (about 2 inches either side of the navel), the love handles, the front of the thigh, and the back of the upper arms. Rotate every injection.
So which should a beginner pick? For everyone, subcutaneous is the answer: absorption is reliable, the needle is tiny, and the doses are so small that a single shot a day during loading is all it takes. There is no real case for intramuscular or oral here.
Reconstitution: mixing it.
Melanotan II arrives as a dry powder, so before you can inject it you reconstitute it, which just means adding liquid to turn the powder into something you can draw into a syringe. It sounds technical but takes about a minute.
Once it is mixed, the only real question is how many units to draw. The doses are small, micrograms rather than milligrams, so it is easy to get wrong by hand. The calculator is worth using.
- Use bacteriostatic water, often called BAC water. The small amount of preservative keeps the mixed vial usable for weeks.
- Add the water slowly, down the inside wall of the vial. A common mix is a 10 mg vial plus 2 mL of BAC water, which gives a concentration of 5 mg/mL.
- Swirl, do not shake. Gently roll the vial until the powder dissolves. Shaking can damage the peptide.
- Store it in the fridge once mixed, and keep it out of direct light.
Open the dosage calculator to turn your vial and dose into an exact number of units. As a worked example: a 10 mg vial mixed with 2 mL of BAC water gives 5 mg/mL, so a 250mcg dose is 0.05 mL, which is just 5 units on a U-100 insulin syringe, and that vial holds about 40 doses.
Dosing by goal.
There is no single official dose for Melanotan II, because it is not an approved medicine. What follows is the range people commonly run, organized by phase. The defining feature of Melanotan II dosing is the loading-then-maintenance pattern, plus starting low to manage nausea.
Loading phase
The most common starting pattern is about 250mcg once daily for two to three weeks, until you reach the tan you want. Many people inject before bed on an empty stomach to sleep through the early nausea. Starting low and going slow is the whole point here.
Maintenance phase
Once you have the tan, people drop to about 250mcg to 500mcg once or twice a week to hold it, rather than continuing daily. The tan fades slowly, so a small weekly top-up is usually enough.
Keeping the total in check
A widely followed guardrail is to keep total daily intake at or below 1mg, and most people stay well under that. Bigger doses mostly mean more nausea and flushing, not a meaningfully better tan.
Once-daily dosing while you build the tan. Start at the low end and dose before bed to ride out the nausea. This is the higher-frequency phase.
Drop to a weekly or twice-weekly top-up to hold the tan, or stop and let it fade. Melanotan II is run in cycles, not indefinitely.
Cycling and timing.
A cycle just means a defined run of time on the peptide, followed by a break. For Melanotan II the common pattern is a loading phase of two to three weeks to build the tan, then a light weekly maintenance dose, then time off once you stop wanting the tan, rather than running it indefinitely.
Why not just run it forever? Mostly because the long-term human safety data does not exist, and there are real concerns around moles and pigment changes. The cautious approach is to run a focused block, watch your skin, then stop.
- Start low at around 250mcg and only build up once you know how the nausea hits you.
- Step down to maintenance once you have the tan, moving to once or twice weekly rather than staying daily.
- Take a real break after a cycle, and keep an eye on your moles. Any changing, growing, or odd-looking spot is a reason to see a dermatologist, not to keep dosing.
Stacking Melanotan II.
Melanotan II is usually run on its own, because it already covers both tanning and libido through the same receptors. A couple of related peptides come up, but stacking is rarely the point.
Tan and libido in one
Most people run Melanotan II by itself. Because it activates all five melanocortin receptors, a single peptide handles both the tan and the libido effect, so there is usually nothing to add.
View stack →Sexual focus, cleaner
If the goal is purely sexual and you do not want the tan or the moles, PT-141 was engineered from Melanotan II to target arousal more selectively. Running both together is redundant rather than synergistic, so people pick one, not both.
View stack →See full recipes, dosing, and how people run them on the stacks page.
Side effects and safety.
Melanotan II has more noticeable side effects than most peptides people run, especially early on. Most are mild and fade as your body adjusts, but a couple are worth taking seriously. The ones people mention most often are:
- Nausea, very common in the first week or two, often peaking a few hours after a dose. Dosing before bed on an empty stomach helps a lot.
- Facial flushing and a warm feeling shortly after injecting.
- Darkening of moles and freckles, and sometimes new ones, because it drives pigment everywhere. This is the one to watch closely.
- Appetite drop, fatigue, and spontaneous yawning or arousal, all tied to the broad melanocortin activity.
Who should be cautious.
Some people have clear reasons to be extra careful, or to avoid Melanotan II entirely until they have spoken with a licensed provider.
- Lots of moles, atypical moles, or a family history of skin cancer. Because Melanotan II darkens and can multiply moles, this is a hard conversation for a dermatologist, not a forum.
- Pregnant or breastfeeding. There is no safety data here, so this is a hard avoid.
- Competing athletes. Melanotan II is prohibited in sport and should be avoided.
- Anyone on other medications or with a chronic condition. Talk to your provider first, especially given the cardiovascular and arousal effects.
And the universal one: whoever you are, talk to a licensed healthcare provider before starting Melanotan II, and get any existing moles checked first. This guide is educational, not a substitute for personalized medical advice.
Where to buy it safely.
This is where a lot of beginners get burned, because peptide quality varies wildly between vendors and the cheapest vial is not always the real deal. Our honest take: do not shop on price alone, shop on price plus independent lab data.
- Compare vendors side by side. Price ranges are wide, and the difference between the lowest and highest listing can be large for the exact same compound.
- Look for recent third-party lab tests. The gold standard the community looks for is a recent Janoshik certificate of analysis showing purity for the batch you are actually buying.
- Favor recent COAs. An old lab result on a different batch tells you little. The fresher the test, the more it means.
- Be skeptical of suspiciously cheap listings with no testing behind them.
That is exactly the comparison we put together. On our Melanotan II product page you can compare vendor prices, see which batches have public lab data, and view the grades we assign from that data. From there you can head to the buy page to line up your options.
Questions, answered straight.
Is Melanotan II legal?
Melanotan II is not an approved drug and is not sold for human use. The FDA has acted against companies marketing it as an injectable tanning product. The vendors we compare offer it strictly for research use only, and it is prohibited in competitive sport. Rules vary by country, so check what applies where you are.
How long until I see a tan?
Most people start to notice deeper color over one to two weeks of daily loading, often with a little sun exposure to bring it out. It builds gradually rather than overnight, which is why the loading phase runs a couple of weeks before dropping to maintenance.
Why does it make me so nauseous?
The nausea comes from activating melanocortin receptors and is very common in the first week or two, often peaking a few hours after a dose. Most people manage it by starting low at around 250mcg and dosing before bed on an empty stomach so they sleep through the worst of it.
Does it really darken moles?
Yes, and this is the main reason to be careful. Melanotan II drives pigment everywhere, so existing moles and freckles darken and new ones can appear. Anyone with lots of moles or a family history of skin cancer should see a dermatologist first and is widely advised to avoid it.
How is it different from PT-141?
PT-141 (bremelanotide) was engineered from Melanotan II to target the arousal receptors more selectively, with little tanning effect, and it is FDA-approved for low sexual desire in women. Melanotan II hits all five melanocortin receptors, so it tans and boosts libido but brings more side effects. Running both is redundant, so people pick one.
Does it need refrigeration?
Keep the sealed, freeze-dried vial in the fridge and out of light. Once you mix it with bacteriostatic water, store it refrigerated and use it within a few weeks. Do not freeze a reconstituted vial.