Melanotan II (MT-2)

Synthetic melanocortin agonist. Tanning (MC1R) and libido/erection (MC4R). NOT FDA-approved. Significantly more side effects than PT-141. Spontaneous erections are a documented side effect.

Educational reference only. This page does not diagnose, prescribe, or replace care from a licensed professional. Laws, availability, and clinical appropriateness vary by location.

Reference doseLoading: 0.25–0.5 mg SubQ daily until desired tan. Maintenance: 0.5–1 mg 2–3x/week

Half-life24 hours

Risk flaghigh

Regulatory noteResearch-only flag

Side effects and watch-outs

Nausea (very common — often severe on initiation)
Facial flushing
⚠️ Spontaneous and prolonged erections — priapism risk (medical emergency if >4 hours)
Increased blood pressure
Yawning and stretching (distinctive neurological effect)
Fatigue
⚠️ Mole darkening — MONITOR ALL MOLES — discontinue if any change in size/colour/shape
⚠️ MELANOMA RISK — DO NOT USE with existing atypical moles or melanoma family history
Freckle formation
Appetite suppression