Melanotan II

• Week 1-2: Nausea and flushing at first; yawning, erections in men
• Week 2-4: Users report the tan building; doses drop after week 3
• Week 4-8: 1-2 shots a week to hold colour; check moles monthly
• Week 8-12: Moles may stay darker; get a skin check; keep sunscreen
• Side effects: ER: 4-hour erection, severe belly/side/muscle pain; see Side effects

More on each stage

Week 1-2

Nausea and facial flushing are most common in the first doses, which is why many start at 250 mcg. You may notice yawning and stretching, less appetite, and (in men) erections that come and go for a few hours after a shot.

Week 2-4

Community users report the tan building over these weeks, faster with sun. In the 1996 pilot study, 2 of 3 men had measurably darker skin 1 week after a 2-week course of 5 doses, so around week 3. Community reports say most side effects fade after the loading phase. The loading phase ends after week 3; from week 4, drop to 500 mcg once or twice a week.

Week 4-8

Maintenance: 1-2 shots a week to hold the colour. Check your moles every month. A new mole, or one that changes shape, colour, or size, needs a dermatologist, not more doses.

Week 8-12

Keep maintenance only as long as you want the colour. Darker moles and freckles may not fully fade after you stop. Book a full skin check if you have not had one. Sunscreen is still needed: a darker tan does not prevent melanoma.

Side effects

Usually nausea, flushing, yawning, less appetite, and spontaneous erections, worst in the first week. Stop and get help for an erection lasting over 4 hours, a changing mole, or severe belly, side, or muscle pain.

Based on what people report in the community sources below. Results vary, and many responses are anecdotal.

• Darker skin with fewer doses

  Human study

  In a 1996 pilot study, 3 healthy men got 5 shots under the skin over 2 weeks. Two had darker skin on the face, upper body, and buttocks 1 week after the last shot, measured with a skin reflectance meter and by eye.1

• A deeper tan when paired with sun

  Community report

  Community guides say almost all users combine it with sun or sunbeds to speed up and deepen the tan. A forum study found many users take it before sun holidays and keep using sunbeds, which adds its own skin-cancer risk.1511

• Erections in men with erectile dysfunction

  Clinical trial

  In a placebo-controlled crossover study, 8 of 10 men with psychogenic erectile dysfunction developed clinically apparent erections during 6 hours of monitoring after a Melanotan II shot (0.025 mg per kg). In a combined group of 20 men, 17 of 20 got erections without sexual stimulation.23

• Higher sexual desire

  Clinical trial

  Men reported more sexual desire after 68% of Melanotan II doses versus 19% of placebo doses (13 of 19 vs 4 of 21).3

• Less appetite

  Clinical trial

  In a placebo-controlled erection trial in 10 men, lower appetite was reported more often after Melanotan II than after placebo, as a side effect. In mice, Melanotan II injected into the brain's reward area cut how much they ate. Users also often report it during loading. It is not a tested weight-loss treatment.21512

What it has been studied for

• Skin tanning (pigmentation) in healthy men1Human study
• Erectile dysfunction in men (psychogenic and organic causes)23Clinical trial
• Low sexual desire in premenopausal women: approved for its spin-off bremelanotide (Vyleesi), not for Melanotan II4FDA-labeled
• Appetite and food intake12Animal/lab study

Melanotan II is a lab-made, ring-shaped copy of the hormone your body releases to tan your skin. Your skin's pigment cells have a lock on the outside, and this hormone is the key. Melanotan II turns that lock, so the cells make more dark pigment (melanin). It is not picky, though. It also gets into the brain and turns similar locks there. That is why the same shot also changes sex drive, erections, and appetite, and causes nausea and yawning.

Peak

Not established in humans for Melanotan II. Its close cousin bremelanotide peaks in the blood about 1 hour after a shot under the skin (range 0.5 to 1 hour). In the 1996 pilot study, erections came and went for 1 to 5 hours after a Melanotan II dose.

Half-life

Not established in humans for Melanotan II. Bremelanotide's half-life is about 2.7 hours (range 1.9 to 4.0 hours).

Cleared

Not established in humans. How long Melanotan II stays in the body has not been measured. The tan lasts much longer than the drug, because the melanin stays in your skin: darker skin was still measured 1 week after the last dose in the pilot study, and dark patches from bremelanotide were not confirmed to fade in every patient after stopping.

Half-life is how long it takes the body to remove half of a dose.418

Once a day for 3 weeks (loading), then once or twice a week to keep the colour. Evening, at bedtime, so you sleep through the worst of the nausea and flushing. Every day during weeks 1-3; from week 4, 1 or 2 days a week (for example Monday and Thursday). Units are for a 10 mg vial mixed with 2 mL water (5 mg per mL).

Step-up plan

When	Dose	Units
Days 1-3 (test dose) Start here	250 mcg	5 units
Day 4 to end of week 3 (loading, every night) Store dose	500 mcg	10 units
Week 4 onward (maintenance, 1-2 times a week)	500 mcg	10 units

• Lower end · test dose; gauges nausea

  0.1-0.25 mg daily for the first few days

  A small test dose many start with for the first 2-3 days to see how bad the nausea and flushing get before moving up. Often injected at bedtime to sleep through the worst of it.1615

• Most common · load daily, then maintain

  0.5 mg daily to load, then 0.5 mg 1-2x weekly

  The most-reported community pattern: 500 mcg daily for about 2-3 weeks until the desired color shows, then the same dose once or twice a week to hold it. Not a trial dose; no study has tested this schedule.1615

• Community dosing guide (The Peptide Catalog; not a study)

  Start at 250 mcg for 2-3 days to test tolerance, then 500 mcg a day at bedtime for 2-3 weeks of loading, then 500 mcg twice a week. Returning users report needing about 2 weeks of loading.16

Research protocols

• 1996 tanning pilot study (3 healthy men)

  Shots under the skin on alternate weekdays for 2 weeks (Melanotan II one day, salt water the next), so 5 Melanotan II doses. Started at 0.01 mg per kg of body weight and rose to 0.025-0.03 mg/kg. The researchers recommended 0.025 mg/kg for future studies. For a 70 kg (154 lb) adult that is 1.75 mg, about 3.5 times the store dose.1

• Erection study (10 men with psychogenic erectile dysfunction, placebo-controlled crossover)

  Shots of 0.025 mg per kg under the skin, compared with placebo shots, with erections monitored for 6 hours after each.2

• Combined erection studies (20 men, placebo-controlled crossover)

  Shots under the skin compared with placebo. At 0.025 mg per kg, 12.9% of men had severe nausea.3

• FDA-approved cousin: bremelanotide (Vyleesi)

  1.75 mg under the skin as needed, no more than once in 24 hours and no more than 8 doses a month. Not the same drug, but the closest approved reference point.4

• Biohacking community (Peptide Protocol Wiki, 500 reports; not a study)

  Loading at 0.25-0.5 mg once a day for 2-4 weeks (first-timers often 0.1-0.25 mg for 3-4 weeks), then 0.25-0.5 mg once or twice a week during sun season. The store plan (500 mcg nightly for 3 weeks, then 1-2 times a week) matches the common pattern.15

Melanotan II is not approved anywhere. The FDA treats it as an unapproved drug, and regulators in Australia and the UK have warned against tanning injections. It darkens moles and freckles, which can hide changes that signal melanoma; dermatologists advise skin checks. Products are unregulated, so purity and dose are uncertain.

Dosing guidance built from the cited research and community reports. It is not a prescription.

On

3 weeks loading, then 1-2 times a week

Break

Stop maintenance when the sunny season ends

A full course at the store pace takes 2 vials. A mixed vial keeps for up to 90 days.

Why the break helps

Stopping when the sunny season ends keeps your total exposure down. Its FDA-approved cousin bremelanotide is limited to 8 doses a month because more frequent dosing caused more dark skin patches (38% of people after 8 daily doses) and more hours of raised blood pressure. Melanomas have been reported during or after Melanotan II use, so the break is a good time for a full skin check by a dermatologist. When people restart, they report needing a shorter loading phase (about 2 weeks instead of 3).

Common

• Nausea, sometimes vomiting, worst in the first few doses

  What to do Start with the 250 mcg test dose, inject at bedtime, and eat lightly before. It usually eases after the first week. If it is severe or does not ease, stop; do not push the dose up.

• Facial flushing, feeling warm

  What to do Usually passes within a couple of hours. If it comes with a racing heart, chest pain, or a pounding headache, see the serious list below.

• Yawning, stretching, tiredness, or sleepiness

  What to do Bedtime dosing helps. In the 1996 pilot study, 1 of 2 men at the highest dose (0.03 mg per kg, about 2.1 mg for a 70 kg adult, roughly 4 times the store dose) had marked sleepiness and tiredness. Do not raise your dose above 500 mcg.

• Spontaneous erections and stronger libido

  What to do Expected; they come and go for a few hours after a shot. An erection lasting more than 4 hours is an emergency (see below).

• Less appetite

  What to do Keep eating regular meals and drinking water. Stop if you are losing weight you did not want to lose.

• Darker freckles and moles, and sometimes new moles

  What to do Photograph your moles before you start and check them every month. Any mole that changes shape, colour, or size, bleeds, or looks different from the others needs a dermatologist.

Stop and get help

• An erection lasting more than 4 hours, especially if painful (priapism)

  What to do Go to the emergency room now. Waiting can cause permanent damage: one man who injected 2 mg had a 30-hour erection that needed surgery, and lasting erection problems afterwards.

• A new mole, or a mole that changes, itches, or bleeds

  What to do Stop Melanotan II and see a dermatologist promptly. A 2025 review lists at least 5 people who got melanoma during or after Melanotan II use. Four had used it for 1 to 7 weeks; three of them were diagnosed 3 to 4 months after their course. All had other risk factors too.

• Severe belly, side, or back pain, dark (cola-coloured) urine, severe muscle pain, or vomiting that will not stop

  What to do Stop and get emergency care. Case reports describe muscle breakdown (rhabdomyolysis), kidney failure, and a kidney infarct (lost blood supply) after Melanotan II.

• Chest pain, a pounding headache, or very high blood pressure

  What to do Stop and get medical help. Melanocortin drugs can raise blood pressure.

• Allergic reaction: hives, swelling of the face, lips, or throat, or trouble breathing

  What to do Call 911 (or your local emergency number) right away.

Do not use if

• You have had melanoma, have a family history of it, or have many or unusual moles.
• You have very fair skin that burns easily, or red hair: these carry a higher melanoma risk. In a 2025 review of 5 melanoma cases after Melanotan II, 4 people had fair skin or red hair.
• You have high blood pressure that is not well controlled, or heart disease: the approved cousin bremelanotide is not allowed for these people.
• You are pregnant, trying to get pregnant, or breastfeeding: there is no safety data.
• You have kidney disease, or have ever had muscle breakdown (rhabdomyolysis): case reports describe kidney failure, a kidney infarct, and muscle breakdown after Melanotan II.
• You have ever had priapism (an erection lasting over 4 hours): Melanotan II has caused priapism that needed surgery.
• You are under 18.

Sources5

Storage

Keep it

Keep the mixed vial in the fridge (2-8 °C / 36-46 °F), in its box, away from heat and light; do not freeze it or leave it in a hot car. Do not use it if it turns cloudy or has bits floating in it.

How long

Use within 90 days of mixing. A mixed vial kept in the fridge holds its strength for 60-90 days, then slowly starts to lose potency. Wipe the rubber top with an alcohol swab before every draw.

Drawing your dose

Syringe: a 0.5 mL (50-unit) U-100 insulin syringe.

1. With this mix, every 1 unit line on a U-100 insulin syringe holds 50 mcg. Draw to the 10-unit line for 500 mcg, or to 5 units for the 250 mcg test dose.
2. Hold the syringe at eye level, flick out air bubbles, and push the plunger back to the exact line. An extra unit here is an extra 50 mcg.
3. Pinch a fold of skin on your belly or thigh, insert the needle at 45 to 90 degrees, push slowly, and wait a few seconds before pulling out.
4. Inject at bedtime on an empty or light stomach. Many users say this makes the nausea easier.
5. Never double a dose to speed up the tan. A man who injected 2 mg (4 times the store dose) had a painful erection lasting 30 hours that needed surgery.
6. Use a new sterile syringe every time and never share one.

• GHK-Cu

  Melanotan II works on skin colour through the pigment cells. GHK-Cu works on skin structure: it raised collagen and elastin and supported skin repair in lab and skin studies. That makes them a skin-care pair with different jobs.141

Interactions

• Erection drugs (sildenafil/Viagra, tadalafil/Cialis)

  Melanotan II causes erections on its own and has caused priapism. No study has tested the combination, so the added risk is unknown.

  What to do Avoid combining. If you do, go to the emergency room for any erection lasting more than 4 hours.

• Naltrexone tablets (for alcohol or opioid addiction)

  Bremelanotide sharply lowered naltrexone levels, which could make it stop working. Not tested with Melanotan II, but bremelanotide is a close cousin made from it.

  What to do Do not use Melanotan II while taking naltrexone tablets without your prescriber's approval.

• Oral medicines that must work fast or keep steady levels (antibiotics, pain relievers)

  Bremelanotide slows stomach emptying and can delay or lower how much of a pill you absorb. Not tested with Melanotan II.

  What to do Avoid Melanotan II while you take a course of antibiotics, and tell your doctor you use it.

• Blood-pressure medicines, or heart disease

  Melanocortin drugs can raise blood pressure; bremelanotide raised it after every dose. One healthy man developed lasting high blood pressure after a kidney infarct linked to Melanotan II.

  What to do Ask your doctor before using it. Do not stop your blood-pressure medicine.

• Sunbeds and heavy sun exposure

  In a 2025 review of 5 melanoma cases after Melanotan II, 3 people had also used sunbeds. A darker tan does not prevent melanoma.

  What to do Skip sunbeds, keep using sunscreen, and get regular skin checks.

Videos

• Melanotan II: The Truth About the Viral "Barbie Drug" | Dermatologist ExplainsDr Dray · 2026
• Stop Taking Melanotan II... Dermatologist Breaks It DownDr. Dustin Portela · 2026
• Unregulated peptide melanotan-II seen to increase risk of abnormal moles | ABC NEWSABC News (Australia) · 2026

Sources

1. 1Dorr et al., Life Sci 1996 (Melanotan II pilot phase I tanning study, 3 men)Clinical trial
2. 2Wessells et al., J Urol 1998 (erections in 10 men, placebo-controlled crossover)Clinical trial
3. 3Wessells et al., Int J Impot Res 2000 (human studies with Melanotan II, 20 men)Clinical trial
4. 4FDA label: Vyleesi (bremelanotide) injection, 2019Drug label
5. 5FDA: Notice of opportunity for hearing (Melanotan II sold as an unapproved new drug)Reference
6. 6Böhm et al., J Eur Acad Dermatol Venereol 2025 (benefits and risks of MC1R activation, incl. melanoma cases after Melanotan II)Review
7. 7Habbema et al., Int J Dermatol 2017 (risks of unregulated melanotan use)Review
8. 8Mun et al., Int J Mol Sci 2023 (MC1R review; bremelanotide is an acid derivative of Melanotan II)Review
9. 9Mallory et al., Sex Med 2021 (priapism after 2 mg Melanotan II)Study
10. 10Peters et al., CEN Case Rep 2020 (kidney infarct after Melanotan II, with literature review)Study
11. 11Gilhooley et al., Dermatology 2021 (Melanotan II user experience on online forums, 205 users)Study
12. 12Eliason et al., Neuropeptides 2022 (Melanotan II in the brain's reward area cut food intake in mice)Study
13. 13Renke & Chinellato, Int J Mol Sci 2026 (therapeutic peptides review: Melanotan II acts on MC1R, MC3R, and MC4R)Review
14. 14Pickart & Margolina, Int J Mol Sci 2018 (GHK-Cu review)Review
15. 15Peptide Protocol Wiki: Melanotan-2 community protocols (500 reports)Community
16. 16The Peptide Catalog: Melanotan-2 dosing guide (community convention)Community

Where people discuss it

• r/Peptides (subreddit)
• Peptide Protocol Wiki — Melanotan-2 community (500 reports)
• The Peptide Catalog — Melanotan-2 dosing

Some peptides, like semaglutide (Ozempic and Wegovy), are FDA-approved medicines. Most of the peptides people research are not. That label sounds like the FDA tested something and turned it down. Usually it means something else: nobody has paid for the studies the FDA needs to see. Here is why.

The FDA doesn’t test drugs. Companies do.

The FDA does not run its own drug tests. A company that wants to sell a new medicine has to test it first, and pay for it. It studies the drug in animals, then in people: first 20 to 100 volunteers, then a few hundred, then up to 3,000. Then it sends all the results to the FDA. FDA scientists review them and decide whether the benefits outweigh the risks.

So approval always starts with a company asking for it. If no company applies, the FDA has nothing to review, however promising the research looks.

Those studies cost about a billion dollars

A study in the medical journal JAMA estimated that bringing one new drug to market costs a typical company about $1.1 billion. That figure includes the money spent on drug ideas that failed along the way, because many drugs that start human testing never make it.

A patent is how a company earns that money back

A patent is a right the government gives an inventor. For up to 20 years from the day the inventor applies, nobody else may make or sell the invention without permission.

For a drug company, that right is what makes the billion-dollar bet worth it. While the patent lasts, the company is the only seller, so it can charge enough to pay back the studies and the failures. When the patent runs out, other companies can sell cheap copies, called generics, and the price drops.

The FDA adds a shorter shield of its own. For 5 years after a brand-new drug is approved, no copycat version can apply for approval. That helps, but it is much shorter than a patent can last.

Why most peptides can’t be patented

To get a patent, an invention has to be new, and it has to be something people made, not something found in nature. Most popular peptides fail one test or both.

They come from nature. Many are copies or small pieces of molecules your body already makes. KPV is a 3-building-block piece of the hormone that tans your skin. BPC-157 is copied from a protein in stomach juice. In 2013 the US Supreme Court ruled that something that exists in nature, like a human gene, cannot be patented just because someone found it and pulled it out.

They aren’t new anymore. Many were first described in research papers decades ago. Scientists were already testing KPV in the 1980s. Once something has been published, it no longer counts as new, so nobody can patent it now, and any patents from back then have long since run out.

Without a patent, a company that paid for the studies would soon face rivals selling the same peptide without having paid for any research. Few companies will spend a billion dollars on a product anyone can copy. So nobody goes first, and the large human studies never happen.

The workaround: change the molecule

Drug companies do make peptide medicines, but they change the peptide first. A changed molecule is a new invention, so it can be patented. Semaglutide is a lab-made version of GLP-1, a gut hormone your body releases after meals, changed so one shot lasts a week. Tesamorelin (Egrifta) is the body’s own growth-hormone signal with a small fatty chain added. Both went through the full studies, and both are FDA-approved.

The natural versions, and the many peptides nobody has changed and patented, stay where they are: studied in labs and animals, used by the biohacking community, and never put through large human trials.

What this means for you

When a peptide is “not FDA-approved,” it usually means no company has paid for the large human studies. It does not mean the FDA tested it and found it harmful.

It also does not mean it is proven safe or proven to work. Without those studies, nobody knows the best dose for sure, or what rare or long-term side effects it may have. And the FDA does not check research peptides for purity or strength the way it checks approved medicines. That is why this page labels every finding by the kind of study behind it, and lists who should not use it.

Sources for this section

1. 1FDA: How drugs are developed and approved (the FDA does not test drugs; companies submit the evidence)
2. 2FDA: The drug development process, step 3: clinical research (study sizes for each phase)
3. 3Wouters, McKee & Luyten, JAMA 2020, corrected 2022: median cost to bring a new drug to market, $1.14 billion
4. 4US patent law, 35 U.S.C. § 154: a patent lasts 20 years from the filing date
5. 5FDA: Frequently asked questions on patents and exclusivity (5-year new chemical entity exclusivity)
6. 6US Supreme Court, Association for Molecular Pathology v. Myriad Genetics (2013): naturally occurring genes cannot be patented