Melanotan II

Unverified protocol notes

Protocol logic check

Independent evidence

Regulatory status: unapproved or compounded peptide with FDA safety risk flag

Storage

No independently verified storage guidance found. Treat any unverified storage claim as unverified, and see the general storage guidance in the FAQ.

Contraindications (limited evidence)

• Personal or family history of melanoma: MT-II's cyclic structure produces higher-affinity MC1R/MC5R agonism than MT-I with greater theoretical oncogenic acceleration potential in cells carrying melanocytic mutations; absolute contraindication; the most critically enforced safety boundary in Category VII. Limited / unverified
• Dysplastic nevus syndrome or multiple atypical moles: highest-risk pre-malignant melanocytic context; absolute contraindication. Limited / unverified
• History of any skin cancer: indicates compromised photoprotective/DNA repair phenotype; contraindicated. Limited / unverified
• Cardiovascular disease (recent MI, unstable angina, severe hypertension): MT-II's substantial MC4R-mediated sympathetic activation produces significant transient blood pressure elevation and tachycardia; the magnitude is greater than PT-141 per mg due to MT-II's higher binding affinity. Limited / unverified
• Concurrent use with Melanotan I: additive MC1R agonism produces no proportional tanning benefit while stacking the full side effect profiles of both compounds; absolute contraindication. Limited / unverified
• Concurrent use with PDE5 inhibitors (sildenafil, tadalafil, vardenafil) in subjects with cardiovascular disease: the combination of MC4R-driven vasodilation from MT-II with PDE5 inhibitor vasodilation can produce severe hypotension in subjects with cardiovascular risk. Limited / unverified
• Known hypersensitivity to MT-II or cyclic alpha-MSH analogs. Limited / unverified
• Pregnancy: not established as safe; MC4R/HPT axis interactions during pregnancy are not characterized. Limited / unverified
• Breastfeeding: no safety data. Limited / unverified
• History of priapism or conditions predisposing to prolonged erection (sickle cell disease, leukemia, multiple myeloma): MT-II's potent MC4R-driven spontaneous erection activity is a direct risk in these populations. Limited / unverified
• Active psychiatric conditions on antipsychotics or mood stabilizers: MC4R dopaminergic overlap with antipsychotic targets. Limited / unverified

Side effects (limited evidence)

• Intense nausea: the most expected, consistent, and severe adverse effect; occurs in the majority of subjects at doses of 250mcg and above; caused by potent MC4R activation in the area postrema; onset 30-60 minutes post-injection; duration 1-4 hours; pre-bed dosing during loading phase is the primary management strategy; significantly more severe than MT-I or PT-141 per microgram due to MT-II's higher MC4R binding affinity. Limited / unverified
• Spontaneous erections: a consistent pharmacological consequence of MC4R hypothalamic activation at standard doses; present in the majority of male subjects; cannot be reliably avoided except through micro-dosing; a defining pharmacological property that distinguishes MT-II from MT-I. Limited / unverified
• Darkening of existing moles and nevi: predictable MC1R-driven eumelanogenesis in all existing melanocytic lesions; all moles must be documented and monitored; any atypical change warrants immediate dermatological evaluation. Limited / unverified
• Facial flushing: intense; MC4R/MC3R-driven cutaneous vasodilation; immediate onset with injection; lasts 1-3 hours; more pronounced than MT-I. Limited / unverified
• New nevus formation: documented in research populations with sustained MT-II use; direct consequence of MC1R-driven melanocyte proliferation. Limited / unverified
• Priapism (prolonged erection): rare but serious; requires emergency medical intervention if erection persists beyond 4 hours; higher risk with MT-II than PT-141 due to greater MC4R potency. Limited / unverified
• Increased libido and spontaneous sexual arousal: a pharmacological effect rather than an adverse event in the sexual health context; problematic in the wrong setting and in subjects not expecting this effect. Limited / unverified
• Transient blood pressure and heart rate elevation: MC4R sympathetic activation produces meaningful hemodynamic changes; more pronounced than PT-141; monitor in subjects with any cardiovascular risk factors. Limited / unverified
• Appetite suppression and weight loss: MC4R hypothalamic agonism suppresses appetite; a secondary effect that becomes clinically significant with prolonged high-dose use. Limited / unverified
• Yawning: a consistent and early signal of MC4R activation onset; typically precedes nausea and arousal effects by 15-30 minutes. Limited / unverified
• Injection site hyperpigmentation: localized darkening at repeated subcutaneous injection sites from local MC1R activation in underlying tissue. Limited / unverified
• Fatigue and post-injection lethargy: as acute MC4R activity resolves, a rebound fatigue phase is common; manageable with pre-bed dosing. Limited / unverified
• MC1R/MC4R receptor desensitization: with high-frequency dosing; the maintenance protocol (twice weekly) is the standard mitigation. Limited / unverified

Compatibility

The relationships below come from the source site's internal engine and were not verified independently. Treat them as a starting point for a conversation with a clinician. They carry no safety guarantee.

Reported synergistic:

Reported contraindicated combinations:

Sources

• https://www.fda.gov/drugs/guidance-compliance-regulatory-information/human-drug-compounding
• https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks?pg=3