Melanotan II
Non-selective melanocortin receptor agonist (MT-II)
Mechanism of Action
Cyclic heptapeptide analog of alpha-MSH. Non-selectively activates MC1R (pigmentation), MC3R/MC4R (appetite, energy homeostasis) and MC4R-mediated central pathways implicated in sexual arousal — explaining its broader effect profile relative to the MC1R-selective Melanotan I.
Key Benefits
- Potent UV-independent tanning, including in poor-tanning skin phototypes
- Increased sexual desire/erectile response reported in controlled human trials (MC4R-mediated)
- Appetite suppression via MC3R/MC4R activation
- Historical basis for development of bremelanotide (PT-141), now FDA-approved as Vyleesi
Dosing Protocol
Human data exists (Wessells/Hadley/Dorr group, University of Arizona) but from a small controlled ED trial — not a safety-established consumer product. Never approved by FDA; its selective descendant PT-141/bremelanotide is.
Ideal Candidates
Research contexts studying non-selective melanocortin pharmacology, MC4R-linked appetite/sexual arousal pathways, or as historical/comparative reference for PT-141 development.
Side Effects & Safety
Nausea and yawning are the most frequently reported effects in human trials (severe nausea in 12.9% of subjects at 0.025 mg/kg); flushing, spontaneous erections, darkening of nevi, and appetite suppression. Nausea is more prominent and frequent than with Melanotan I.
Regulatory Status
RestrictedNot FDA-approved in any form; FDA has issued warning letters against MT-II marketing. Its truncated/modified analog bremelanotide (PT-141) is FDA-approved as Vyleesi (2019) for HSDD — MT-II itself remains an unapproved research compound.
Evidence & Citations
- Wessells H, Levine N, Hadley ME, Dorr R, Hruby V. Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II. Int J Impot Res. 2000;12(Suppl 4):S74-9.
- Levine N, et al. Induction of skin tanning by subcutaneous administration of a potent synthetic melanotropin. JAMA. 1991;266(19):2730-6.
Frequently asked
What is Melanotan II?+
Melanotan II (Non-selective melanocortin receptor agonist (MT-II)) is a peptide studied for non-selective mc receptor agonism and tanning + libido effects. Cyclic heptapeptide analog of alpha-MSH. Non-selectively activates MC1R (pigmentation), MC3R/MC4R (appetite, energy homeostasis) and MC4R-mediated central pathways implicated in sexual arousal — explaining its broader effect profile relative to the MC1R-selective Melanotan I.
What is the dosing protocol for Melanotan II?+
Literature commonly references 0.25 mg/day (loading) (low) to 1 mg 2–3x/wk (maintenance) (maintenance) via SubQ, on a 10–20 day loading phase, then ongoing maintenance cycle. Educational reference only — a licensed Stackhaus Health provider sets any personalized protocol.
What is the regulatory status of Melanotan II?+
Not FDA-approved in any form; FDA has issued warning letters against MT-II marketing. Its truncated/modified analog bremelanotide (PT-141) is FDA-approved as Vyleesi (2019) for HSDD — MT-II itself remains an unapproved research compound.
Where can I access Melanotan II?+
Research-grade Melanotan II is available through Stackhaus Research. For a personalized, provider-reviewed protocol, consult a licensed clinician through Stackhaus Health.