Melanotan II Dosage, half-life & reference guide

Also known as MT-2 · MT2 · Melanotan 2

A broad-spectrum melanocortin agonist originally developed for sunless tanning. MT-2 stimulates melanocytes to produce melanin (it works without sun; UV exposure speeds and deepens the tan), increases libido through central nervous system pathways, and can reduce appetite. PT-141 is a close analog, developed for sexual function after MT-2 caused erections in trials.

Studied range
250–500 mcg
How often
Daily
Evidence
●●● Emerging
Route
SubQ injection

Studied in research — not a recommendation.

Melanotan II dose guide

How it works.

Melanocortin receptor agonist (MC1R, MC3R, MC4R, MC5R). Stimulates melanogenesis (skin tanning), increases libido via CNS pathways, and can reduce appetite (a side effect in one small trial; the MC4R appetite mechanism comes from rodent work). Structurally similar to alpha-MSH.

Commonly reported: Nausea and facial flushing after the first doses, easing with continued use; a fast, deep tan with freckles and moles visibly darkening; and spontaneous erections, frequent yawning and reduced appetite. Monitor moles carefully — it darkens all pigmented skin, and FDA cites melanoma reports.

Where Melanotan II works.

A body with Skin & hair and Sex & hormones lit

  • Skin & hair

    In people. MT-2 stimulates melanocytes to produce melanin (it works without sun; UV exposure speeds and deepens the tan).

  • Sex & hormones

    In people. PT-141 is a close analog, developed for sexual function after MT-2 caused erections in trials.

An area lights for what a peptide is used for and what people report, with the evidence beside it. It isn’t a promise that it works there.

Week by week.

What to expect in the first 8 weeks

Onset
1–3 days
Peak effect
2–4 weeks
Duration
Loading 1–2 weeks, then maintenance ongoing

  1. Day 1–3Community

    Start low — your body needs to adjust

    Commonly reported: nausea and flushing on the first few doses, easing as you continue. Many start low and dose in the evening to sleep through the worst of it. The tanning effect hasn't started yet; this is your body adapting to the melanocortin activation.

    The science

    MT-2 activates MC1R (melanogenesis), MC3R (energy/sexual), MC4R (appetite/arousal) and MC5R simultaneously. The nausea involves MC4R in the brainstem's nausea center, and starting low is the community's way to let tolerance build; neither has been studied. In the first human pilot, nausea occurred at most dose levels (Dorr 1996).

    Sources
    • Dorr et al. (1996)

    Updated Sep 2026

  2. Day 3–7Clinical

    Melanocytes are waking up

    After a few days of loading, your pigment cells are being switched on. Sun exposure speeds this up, but it isn't required: in the first human study, skin darkened even where the sun doesn't reach. Commonly reported: brief facial flushing after doses, which is a side effect of the drug itself, not the tan starting.

    The science

    MT-2 binding to MC1R upregulates tyrosinase and other melanogenic enzymes within melanocytes. In a normal suntan, UV damage triggers (via p53) the skin's own tanning hormone, alpha-MSH (Cui 2007); MT-2 mimics that hormone, so it can skip the UV step. Five low doses raised pigmentation in the face, upper body and buttock (Dorr 1996), and UV adds to the effect.

    Sources
    • Dorr et al. (1996)
    • Cui et al. (2007)

    Updated Sep 2026

  3. Day 7–14Community

    The tan is developing

    Commonly reported one to two weeks in: a noticeably developing tan (faster with sun), freckles and moles darkening, libido effects and reduced appetite. Monitor any existing moles and get a baseline skin check if you haven't.

    The science

    Cumulative MC1R stimulation, with or without UV, produces eumelanin deposition in the epidermis. Mole darkening occurs because nevus melanocytes are also MC1R-positive and respond to the same signal; case reports describe new and changing moles, and melanoma in users (Hjuler & Lorentzen 2014). Dermatological monitoring is recommended.

    Sources
    • Dorr et al. (1996)
    • Hjuler & Lorentzen (2014)

    Updated Sep 2026

  4. Day 14–28Community

    Transition to maintenance

    Most users achieve their desired tan level by week 2–3 and drop to maintenance dosing (250–500 mcg, 2–3x per week). The nausea should be long gone by now. Less UV is needed to maintain the tan than to build it.

    The science

    Once melanocyte priming is established, lower-frequency MC1R stimulation maintains melanin production. A drug-assisted tan lasts longer than a UV-only tan: with its close relative melanotan-I, the tan held at least 3 weeks longer than sun alone (Dorr 2004).

    Sources
    • Dorr et al. (2004)

    Updated Sep 2026

  5. With PT-141Community

    MT-2 is PT-141's parent compound

    PT-141 is a close analog of MT-2 that was developed specifically for sexual function. If you're already on MT-2, the libido boost is built in — adding PT-141 on top is redundant for that effect. MT-2 is the broader tool; PT-141 is the as-needed one.

    The science

    MT-2 activates MC1R/MC3R/MC4R broadly. PT-141 (bremelanotide) is MT-2's C-terminal acid analog (same ring structure); it is still a nonselective melanocortin agonist and still causes skin darkening with frequent use. Using both hits the same receptor population.

    Sources
    • Hadley & Dorr (2006)

    Updated Sep 2026

  6. Any dayCommunity

    What Melanotan II is built on

    MT-2 was developed at the University of Arizona in the 1980s as a potential skin cancer prevention drug. It has no FDA approval and only a few small completed trials, yet it's one of the most widely used peptides globally. Safety data comes mostly from community use and case reports, and FDA cites melanoma, a brain-swelling syndrome (PRES) and priapism — get regular skin checks.

    The science

    Cyclic lactam analog of alpha-MSH with broad melanocortin receptor affinity. A small University of Arizona pilot study showed MT-2 tans skin without UV (Dorr 1996); its later trials were in erectile dysfunction (Wessells 1998, 2000). Development moved to sexual dysfunction (it became the parent of PT-141), while the tanning work continued with its linear cousin melanotan-I (afamelanotide, approved as Scenesse for EPP).

    Sources
    • Dorr et al. (1996)
    • Wessells et al. (1998)
    • Hadley & Dorr (2006)

    Updated Sep 2026

Day 1 is the day you start it.

Developed in academic research. Only a few small completed trials (a tanning pilot and erectile-dysfunction studies). Extensive global community use with well-documented effects.

Preliminary research

Mixing and a typical run.

Example numbers

Reconstitution example

Reconstitute a 5 mg vial of Melanotan II with 2 mL of bacteriostatic water and a 375 mcg dose is 15 units on a U-100 syringe, about 13 doses per vial.

Vial
5 mg
Water
2 mL
Amount
375 mcg

Draw to15 units

0.3 mL insulin syringe · 30 units

Mix it in the Reconstitution LabOpen the calculator

Run notes

Cycle
Loading phase until desired tan achieved, then reduce to maintenance. Sun or UV exposure enhances tanning effect.Community practice — opinions vary. Not a clinical recommendation.
Timing
Evening dosing is common, to sleep through the nausea. Many start low (100-150mcg) to assess tolerance.
Route
SubQ injection
Stacks
PT-141

Safety.

Common side effects

  • Nausea
  • Facial flushing
  • Spontaneous erections
  • Fatigue
  • Darkening of moles/freckles
  • Yawning

Goes with.

Questions people ask.

What is Melanotan II?

A broad-spectrum melanocortin agonist originally developed for sunless tanning. MT-2 stimulates melanocytes to produce melanin (it works without sun; UV exposure speeds and deepens the tan), increases libido through central nervous system pathways, and can reduce appetite. PT-141 is a close analog, developed for sexual function after MT-2 caused erections in trials.

How is Melanotan II dosed in research?

The research range for Melanotan II is 250–500 mcg. Loading: 250mcg daily for 1-2 weeks. Maintenance: 250-500mcg 2-3x/week or as needed. Studied in research — not a recommendation.

How long does Melanotan II last?

The half-life of Melanotan II is unknown in humans.

What do people report on Melanotan II?

Commonly reported on Melanotan II: nausea and facial flushing after the first doses, easing with continued use; a fast, deep tan with freckles and moles visibly darkening; and spontaneous erections, frequent yawning and reduced appetite. Monitor moles carefully — it darkens all pigmented skin, and FDA cites melanoma reports.

Is Melanotan II safe?

The research basis for Melanotan II is emerging: primarily preclinical / limited human data. Common side effects in the library: nausea, facial flushing, spontaneous erections, fatigue, darkening of moles/freckles and yawning.

What does Melanotan II stack with?

Common stacks for Melanotan II: PT-141.

Research.

The literature

Search the latest research

PubMedGoogle Scholar

Reference.

Cadence

Daily

Loading: 250mcg daily for 1-2 weeks. Maintenance: 250-500mcg 2-3x/week or as needed.

Half-life

Unknown in humans

Research basis

●●● Emerging

Primarily preclinical / limited human data

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