Melanotan-2
Also known as MT-2, MT-II, Melanotan II, Cyclic alpha-MSH analog
Melanotan-2 is a cyclic alpha-MSH analog that darkens skin quickly and also boosts libido and suppresses appetite because it hits several melanocortin receptors at once. It is the most widely used tanning peptide and the one with the most side effects.
Reviewed by the amino101 editorial team. , first published .
Quick start
What people commonly do. Not a prescription.- Typical dose
- 0.25 to 1 mg
- How often
- daily during loading, then 1 to 2 times weekly
- Where
- Subcutaneous, belly or thigh; intranasal is used by some but absorption is unreliable
- Timing
- evening on a light stomach so nausea passes during sleep; some UV exposure a few times a week
- Effects timeline
- nausea and flushing within an hour of the first doses, visible darkening within 1 to 2 weeks, full tan in 2 to 3 weeks
- Storage
- fridge 2 to 8 C once mixed, use within 4 weeks; lyophilized in freezer or fridge away from light
- Cycle length
- 2 to 3 week loading phase, then maintenance as desired
- Break between
- stop daily dosing once the shade is reached and maintain weekly; the tan fades over 1 to 2 months if stopped fully
Overview
Melanotan-2 came out of the same University of Arizona program that produced melanotan-1. Researchers shortened the peptide to seven amino acids and cyclized it with a lactam bridge, which made it smaller, more stable, and more potent. Unlike melanotan-1, which is selective for the MC1R receptor on skin, melanotan-2 is a broad agonist across MC1R, MC3R, MC4R, and MC5R. That broad activity is why early human studies reported not only tanning but also spontaneous erections, yawning, stretching, and reduced appetite. The erection finding directly led to the development of PT-141.
Human data comes from a handful of small studies in the 1990s. Volunteers given melanotan-2 subcutaneously for a week or two developed noticeable darkening, especially on the face, arms, and neck, with the effect greatest in fair skinned people. Men with erectile dysfunction had improved erections in a small placebo controlled trial. Nausea and vomiting were common, along with flushing, fatigue, and appetite loss. Development as a drug was abandoned in favor of melanotan-1 for pigmentation and PT-141 for sexual function, and melanotan-2 has existed since as a grey market product.
It is popular because it works fast, is cheap, and the extra effects on libido and appetite are often welcome. The concerns are real though. Nausea at the start is nearly universal. Darkening of moles and the appearance of new ones is reliably reported and has prompted case reports of melanoma diagnosed in users, though causation has not been established. Regulators in the UK, Australia, and elsewhere have warned against it. There is no long term safety data of any kind, and product quality is a lottery. Melanotan-1 is the better choice for anyone who wants the tan without the rest.
How it works
Melanotan-2 activates melanocortin receptors throughout the body. At MC1R on melanocytes it raises cAMP and drives tyrosinase to produce eumelanin, darkening the skin. At MC4R in the hypothalamus it increases sexual motivation and produces erections through central pathways, the same mechanism as PT-141, and it suppresses appetite through the same receptor, which is the pathway that anti-obesity melanocortin drugs like setmelanotide target. MC3R activation contributes to energy balance effects. The cyclic structure protects the peptide from breakdown and improves receptor binding, so effects last several hours from a single dose. The nausea and yawning appear to come from central melanocortin signaling in the brainstem.
Where the research stands
Tanning and skin darkeningModerate evidence
- Skin darkening in healthy volunteers. Small human pilot studies from the 1990s showed significant darkening after about 2 weeks of daily injections, most on the face and neck.
- Protection for fair skin. Effect was largest in fair skinned volunteers, but no study has followed users long enough to show reduced sunburn or skin cancer.
Erectile dysfunction and libidoModerate evidence
- Psychogenic erectile dysfunction. A small placebo controlled crossover trial in men showed improved erections; this finding led directly to PT-141.
- Increased sexual desire. Reported consistently in volunteers and by users, but never measured as a primary outcome in a controlled trial.
Appetite suppressionEmerging
- Reduced food intake. MC4R agonism lowers food intake and body weight in rodents, and reduced appetite was reported in human pilot studies, but it is not a studied or reliable weight loss use.
- human pilotSubcutaneous melanotan-2 for 2 weeks produced significant skin darkening in healthy men, most pronounced on the face and neck.
- human RCTMelanotan-2 improved erectile function in men with psychogenic erectile dysfunction in a small placebo controlled crossover trial.
- human pilotNausea, stretching, yawning, and reduced appetite were reported at doses effective for tanning.
- rodentMC4R agonism reduces food intake and body weight in rodent models of obesity.
- human pilotCase reports describe new or changing melanocytic lesions, including melanoma, in melanotan-2 users, without established causation.
Rodent and in vitro mean no human data for that finding. Human pilot means small, often uncontrolled. Human RCT means randomized and controlled. Clinical means an approved drug with regulatory data.
Levels over time
Modeled from the half-life. Illustrative, not measured.A half-life of 1 h against dosing every 24 h means each dose has cleared before the next. Nothing stacks; you start from zero every time, and the tissue effect is what carries over.
The peptide clears within hours, which is why nausea, flushing, and erections cluster right after dosing, while the tan builds from repeated daily doses over weeks.
Melanotan-2 dosage and protocols
Start at 0.25 mg and hold there until the nausea fades, then step up to 0.5 mg daily for a 2 to 3 week loading phase. Once the shade is reached, drop to 0.5 to 1 mg once or twice a week. Many people switch to melanotan-1 for maintenance to avoid the side effects.
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| Nausea test, first days | 0.25 mg | once daily | Subcutaneous, evening |
| Loading, typical | 0.5 mg | once daily | Subcutaneous, evening |
| Loading, high tolerance | 1 mg | once daily | Subcutaneous, evening |
| Maintenance | 0.5 to 1 mg | 1 to 2 times weekly | Subcutaneous |
Evening on a light stomach, not empty and not full. Two or three short UV sessions a week during loading. Keep it away from alcohol, and do not dose on the same day as stimulants or a PDE5 inhibitor because of the blood pressure and nausea overlap.
start at 0.25 mg to test nausea response; 0.5 mg daily is a typical loading dose
Dose calculator
U-100 insulin syringeUnits are a volume on the syringe, not an amount of peptide. Concentration changes every time you change the water volume. The standalone calculator explains the math.
| Vial | Suggested water | Concentration | Low dose draw |
|---|---|---|---|
| 10 mg | 2 mL | 5 mg/mL | 5 units |
How to reconstitute Melanotan-2
- 1
Wash your hands and wipe the work surface. Swab both vial stoppers with alcohol and let them dry.
- 2
Pick the water volume with the calculator above and write it on the vial. The concentration means nothing without it.
- 3
Draw the bacteriostatic water into a mixing syringe.
- 4
Insert at an angle and let the water run down the inside wall. Never squirt it straight onto the powder.
- 5
Swirl gently or leave it to dissolve. Do not shake.
- 6
Label with the date and water volume. Store in the fridge at 2 to 8 C and use within about 4 weeks.
- 7
Unmixed vials keep for months in the fridge and longer in the freezer, sealed and out of light.
- Full walkthrough with syringe reading and site rotation: reconstitution guide.
- ✓White, fluffy cake
Lyophilized powder should look like a small white puck or fluffy cake at the bottom of the vial. That is a proper freeze-dry.
- ✓Clear after mixing
Once dissolved the solution should be water-clear with nothing floating in it.
- !Slight clumping
Small clumps that dissolve with gentle swirling are fine. Shipping compacts powder.
- ✕Collapsed or melted
Powder stuck to the sides, glassy, or shrunken means it got hot in transit. Contact the vendor.
- ✕Cloudy or particles
Persistent cloudiness or visible particles after mixing means degraded or contaminated product. Do not use it.
- First 3 to 5 days
Nausea, flushing, yawning, and stretching after each dose; men often get spontaneous erections; appetite drops. Little visible change yet.
- Week 1 to 2
Darkening begins, first on the face, neck, and arms; moles and freckles get darker; nausea usually fading.
- Week 2 to 3
Full tan with regular UV exposure; time to drop to maintenance.
- Maintenance and after
Weekly doses hold the shade; if stopped, the tan fades over 1 to 2 months while moles may stay darker longer.
Interactions and stacking
Melanotan-1compatible
Commonly alternated, MT-2 to load and MT-1 to maintain; using both the same day just adds nausea.
PT-141avoid
PT-141 is essentially the sexual metabolite of MT-2, so combining them doubles the MC4R load, the nausea, and the blood pressure rise for no gain.
Semaglutide and other GLP-1 drugscaution
Both suppress appetite and cause nausea; together people can end up eating very little and feeling ill.
PDE5 inhibitors (sildenafil, tadalafil)caution
Used together by some men, but flushing, headache, and blood pressure swings add up.
Stimulants (amphetamines, high dose caffeine)caution
MT-2 can nudge blood pressure up; stimulants add to that.
Alcoholcaution
Makes the nausea and flushing worse, especially during loading.
History of melanoma or many atypical molesavoid
Case reports link new and changing moles, including melanoma, to MT-2 use; causation is unproven but the risk is not worth it in this group.
Safety
- ▲Nausea and sometimes vomiting, nearly universal for the first several doses
- ▲Flushing and facial redness
- ▲Darkening of moles and freckles, and new moles appearing
- ▲Spontaneous erections and increased libido
- ▲Reduced appetite
- ▲Fatigue, yawning, and stretching after dosing
- ▲Nausea and sometimes vomiting, especially for the first several doses; start very low and dose at night.
- ▲Darkens existing moles and freckles and can produce new ones; melanoma has been reported in users, so document your skin and get any changing mole checked.
- ▲Spontaneous erections, increased libido, and reduced appetite are expected and can be unwelcome.
- ▲Flushing, fatigue, yawning, and stretching are common; a small blood pressure rise is possible.
- ▲Unregulated product; several health authorities have issued warnings, and contamination and mislabeling are documented.
- ■A mole changes size, shape, color, or border, or a new dark lesion appears
- ■Nausea does not settle after a week at the lowest dose
- ■Blood pressure runs high or you get headaches with dosing
- ■Sexual side effects or appetite loss are interfering with daily life
- ■A new vial behaves very differently from the last, which points to mislabeling or contamination
Community poll
Self-reported by visitors. Not clinical evidence.Melanotan-2: frequently asked
How do I minimize the nausea?
Start at 0.25 mg or less, inject in the evening on a light stomach, and stay at that dose until the nausea fades before increasing. Most people adapt within a week. Antihistamines or ondansetron help if it is bad. If it never settles, switch to melanotan-1.
Why are my moles getting darker?
Because the peptide stimulates every melanocyte in your body, and moles are clusters of melanocytes. This is expected and usually reverses after stopping, but it makes monitoring for melanoma harder. Take photos before starting and see a dermatologist about anything that changes shape, size, or has irregular borders.
Will it make me lose weight?
It reduces appetite through the same brain receptor that obesity drugs like setmelanotide target, so many people eat less, especially early on. It is not a reliable weight loss tool and the effect fades, but it is noticeable enough that some people use it partly for that reason.
Is it legal?
In most countries it is not approved for sale as a medicine and is sold as a research chemical. The UK, Australia, and several EU countries have issued specific warnings. Possession is generally not a crime but selling it as a tanning product is.
References
- Melanotan-II, a cyclic alpha-MSH analog, induces tanning in human volunteers. Journal of Clinical Endocrinology and Metabolism, 1996
- Double blind, placebo controlled evaluation of melanotan-II in men with psychogenic erectile dysfunction. Journal of Urology, 1998
- Melanotan-associated melanoma and changing melanocytic naevi: case reports and review. British Journal of Dermatology, 2009