Peptide Safely
Some human studiesTanning

Melanotan II

Also called Often abbreviated MT-II, Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2

Unapproved tanning shot that also raises sex drive and cuts appetite, with real skin risks.

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Typical dose0.01–0.03 mg per kg (about 0.7–2 mg for a 70 kg adult)
How oftenEvery other day in the study
Half-lifeNot well studied in people; its effects outlast the drug in the blood
Vial sizes10 mg

The simple version

What it does
It darkens your skin and can also raise sex drive and lower appetite.
How people take it
In an early study, 0.01–0.03 mg per kg (about 0.7–2 mg for a 70 kg adult) was injected every other day.
Know this
It's unapproved with no long-term safety testing, and users have reported changing moles and melanomas.

What it is

Melanotan II is a lab-made, ring-shaped cousin of the body's tanning hormone, first tested by University of Arizona researchers in the 1990s. It was never approved anywhere, but it's sold online as a 'tanning jab' or nasal spray. The drug bremelanotide (PT-141) was developed from it.

How it works

It switches on several hormone receptors at once. Some on pigment cells darken your skin, and others in the brain affect sex drive and appetite. That's why one shot can cause a tan, surprise erections, nausea and less hunger all at once.

What people use it for

  • Tanning without much sun
  • Sex drive or erections (not approved)
  • Appetite control (not approved)

The evidence

Some human studies

Tiny early studies in men showed it darkens skin and triggers erections at about 0.025 mg per kg, but no large or long-term safety trials were ever done. Case reports describe moles changing or darkening, new moles, melanomas found in users, priapism (painful erections that won't go away), and kidney and other problems. It's not proven to cause melanoma, but doctors are worried.

How people dose it

Label doseFDA labelTrial doseclinical trialsReportedcommon use, untested

Early human study

Trial dose
Dose
0.01–0.03 mg per kg (about 0.7–2 mg for a 70 kg adult)
How often
Every other day in the study
When
Any time
Cycle
2 weeks in the study
Route
Subcutaneous injection

Why: From a 3-person pilot study. The top dose caused strong tiredness and sleepiness, and nausea showed up at most doses.

Low/starter

Reported
Dose
0.1–0.25 mg
How often
Once a day for the first few days
When
Evening, so nausea and flushing hit while resting
Cycle
Until you know how you react
Route
Subcutaneous injection

Why: Users start very low to test for nausea, vomiting and blood-pressure effects before going higher.

Loading

Reported
Dose
0.25–0.5 mg
How often
Once a day
When
Evening
Cycle
Usually 1–3 weeks until the desired shade
Route
Subcutaneous injection

Why: This is a commonly reported community pattern. Tanning builds faster with some UV, which adds to skin-cancer risk.

Maintenance

Reported
Dose
0.5–1 mg
How often
Once or twice a week
When
Evening
Cycle
As long as the color is wanted
Route
Subcutaneous injection

Why: Color fades slowly, so users drop to weekly doses once tanned. Long-term use has never been studied.

Start at the low end, and change one thing at a time. If you take medication or have a health condition, check with a doctor first.

Mix & measure

Set up for a 10 mg vial. Change any number to match yours. New to this? Read how to mix a vial and mg vs mL vs units first.

mg
mL
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Plan your supplies

Pick your dose and how long you'll run it. We'll count what you need.

µg
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We may earn a commission from these links. Counts include one syringe and two swabs per dose.

Stay safe

Side effects

  • Nausea and vomiting, especially at first
  • Face flushing
  • Yawning and stretching
  • Surprise erections; priapism (an erection lasting over 4 hours is an emergency)
  • Loss of appetite
  • Moles getting darker, changing shape, or new moles showing up
  • Freckles and patchy dark spots
  • Tiredness and sleepiness
  • Higher blood pressure or racing heart

Skip it if

  • You or family have had melanoma or skin cancer
  • Lots of moles, or unusual-looking moles
  • Heart disease or high blood pressure
  • Past priapism, or using ED drugs
  • Pregnant or breastfeeding
  • Under 18

Interactions

  • ED drugs like sildenafil or tadalafil: higher risk of priapism
  • Bremelanotide (PT-141): hits the same receptors, so side effects stack
  • Blood-pressure medicines: may act less predictably

Get help right away for swelling of the face or throat, trouble breathing, chest pain, or a spreading, hot, red injection site.

Storage & legal

Storage

Powder: fridge or freezer, out of the light. Once mixed: fridge, and use within about 4 weeks.

Legal status

FDA: Not approved for any use. It was taken off FDA's 'do not compound' list in April 2026 and is pending advisory review, expected by early 2027.

Sport (WADA): Not named, but as a substance with no approval for human use it falls under S0 (non-approved substances), banned at all times.

Common questions

Does it cause melanoma?

That's not proven. But doctors have reported moles changing fast and melanomas found in users, so if you've used it, get a full skin check and watch any mole that changes.

Do I still need sun?

Most users find some UV speeds up tanning. UV is the main known cause of skin cancer, so this adds risk.

What if an erection won't go away?

An erection lasting more than 4 hours is a medical emergency, so go to an ER. Waiting can cause permanent damage.

Sources

  1. Dorr RT, et al. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sci. 1996;58(20):1777-84. PubMed 8637402
  2. Wessells H, et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study. J Urol. 1998;160(2):389-93. PubMed 9679884
  3. Langan EA, et al. Change in moles linked to use of unlicensed "sun tan jab". BMJ. 2009;338:b277. PubMed 19174439
  4. Habbema L, et al. Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review. Int J Dermatol. 2017;56(10):975-980. PubMed 28266027
  5. Mallory CW, et al. Melanotan Tanning Injection: A Rare Cause of Priapism. Sex Med. 2021;9(1):100298. PubMed 33460908

Last checked 2026-10