Melanotan II
(Ac-Nle4, Asp5, D-Phe7, Lys10)-MSH4-10-NH2
A synthetic melanocortin peptide studied for tanning and erections in small 1990s trials.
Melanotan II is a synthetic analog of the naturally occurring alpha-melanocyte-stimulating hormone (alpha-MSH). Originally developed at the University of Arizona as a possible sunless tanning agent, it stimulates the body's natural pigmentation process. Small 1990s trials also recorded erections and reduced appetite. As of October 2026, it isn't approved for any use.
Read the research profile for mechanisms, citations, and safety context before comparing vendors. View the Melanotan II research profile.
Key Benefits
Mechanism of Action
Melanotan II is a non-selective agonist at melanocortin receptors (MC1, MC3, MC4, MC5). Binding to the MC1 receptor on melanocytes stimulates melanin production, which darkens the skin. Activation of the MC4 receptor in the brain is thought to drive the erections and appetite changes seen in trials.
Dosing Guidelines
Typical Dose
100-500 mcg
Frequency
Daily or every other day
Duration
2-4 week loading phase, then as-needed maintenance
Note: These figures come from vendor and user guides, not trials. Users commonly report starting around 100 mcg by subcutaneous injection, often at night because of nausea. The 1990s trials used weight-based doses in men (0.01-0.03 mg/kg). Many users pair it with sun or sunbed exposure; a 2014 melanoma case report involved both. As of October 2026, it isn't lawfully compoundable in the US (FDA advisers review it by February 2027), and WADA's S0 category bans unapproved substances.
Research & Studies
An overview of Melanotan II's action on melanocortin receptors and what small human trials found on tanning, erections and appetite.
Read Full ResearchTrial data on erections and sexual desire in men with erectile dysfunction via MC4R activation.
Read Full ResearchExamines the idea that more eumelanin could protect skin from UV damage, which no human study has tested for Melanotan II.
Read Full ResearchPotential Side Effects
Reported side effects may include:
- - Nausea (trials; severe in about 13% of men at the 0.025 mg/kg trial dose)
- - Facial flushing after injection (user reports and vendor lists)
- - Spontaneous erections, yawning and stretching (trials)
- - Darkening of existing moles and new moles or freckles (case reports and user reports)
- - Decreased appetite (1998 trial) and fatigue (1996 pilot)
- - Melanoma, including a 2025 oral case after nasal spray use (case reports; cause not proven)
- - Priapism, PRES (a brain-swelling syndrome) and sympathomimetic toxidrome (case reports cited by FDA)
This information is for research purposes only. Always consult with a healthcare professional.
Popular Stacking Options
Melanotan II + Ipamorelin / CJC-1295
Some users pair MT-II with a GHRH/GHRP cycle for appearance and body-composition goals. The combination hasn't been studied.
Shop this stackMelanotan II + BPC-157
Users sometimes add BPC-157 for recovery and gut goals; its evidence is mostly rodent data, and the pairing hasn't been studied.
Shop this stackMelanotan II + GHK-Cu
Users describe a skin stack: MT-II for color, GHK-Cu for collagen. GHK-Cu's human data are small topical studies, and the combination hasn't been studied.
Shop this stackFrequently Asked Questions
How long does it take for Melanotan II to start working?
Users commonly report a visible change in skin tone after 1-3 weeks, often with some UV exposure. In the 1996 pilot, 2 of 3 men had measurably darker skin a week after dosing ended. In the trials, erections came on within hours of a dose.
Is the tan from Melanotan II permanent?
No. Users report that the tan fades over several weeks to months after stopping, as skin cells turn over. We found no study that measured how long it lasts.
How can I avoid the nausea from Melanotan II?
Nausea was the most common side effect in the trials. Users and vendor guides describe starting around 100 mcg and dosing right before bed; these are community practices, not tested methods. Persistent nausea is a reason to stop and talk to a healthcare professional.
Will Melanotan II really make my moles darker?
Very likely. Case reports and user reports describe darker existing moles and new ones, in one case within 24 hours of a single injection. A 2017 review counted four melanoma case reports linked in time to melanotan use, and more have followed. Case reports can't prove cause, but any changing mole is worth showing to a dermatologist.
What's the difference between Melanotan I and Melanotan II?
Melanotan I (afamelanotide) is more selective for the MC1 receptor, so its main effect is pigmentation. It's a prescription medicine (Scenesse, an implant FDA approved in 2019 for a rare light-sensitivity disorder), and research-use-only versions aren't equivalent. Melanotan II hits several receptors, which is why trials saw erections and appetite changes (MC4R) along with tanning (MC1R).
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