Melanotan 2

Melanotan II (MT-II) is a synthetic melanocortin peptide analog studied for its activity at melanocortin receptors (notably MC1R for melanogenesis and MC3R/MC4R for appetite/sexual function signaling). It is researched for pigmentation/tanning effects and for central effects related to libido and appetite, but it is also associated with notable adverse effects and safety concerns.

— 10 mg Vial —

Reconstitute: Add 3.0 mL bacteriostatic water → 3.33 mg/mL concentration.
Typical daily range: 250–1000 mcg once daily (gradual titration over 8–12 weeks).
Easy measuring: At 3.33 mg/mL, 1 unit = 0.01 mL ≈ 33.3 mcg on a U-100 insulin syringe.
Storage: Lyophilized: freeze at −20 °C or below; reconstituted: refrigerate at 2–8 °C, use within 1–2 weeks.

Schedule: Daily subcutaneous injections for 6–8 weeks during loading phase, then maintenance dosing 1–2× weekly.
Cycle Length: 6–8 weeks for initial tanning, then switch to maintenance dosing.
Goal: Increase skin pigmentation (tanning) through melanocortin receptor activation.

Frequency: Inject once daily subcutaneously during the initial 8-week tanning phase; transition to 1–2 injections per week for maintenance dosing.

• Increases eumelanin production via MC1R activation (enhanced pigmentation in many subjects).
• May reduce UV-induced damage risk by increasing melanin (protective hypothesis; not a substitute for sunscreen).
• May suppress appetite in some individuals via central melanocortin pathways (MC4R-related).
• Reported increases in libido/sexual function in some research contexts (central melanocortin effects).

MT-II is a non-selective melanocortin receptor agonist. Activation of MC1R on melanocytes increases cAMP signaling and upregulates melanogenesis. Activation of MC3R/MC4R in the CNS influences energy balance and sexual-behavior pathways. Non-selectivity contributes to both desired effects and side effects.

Potential adverse effects reported in literature and/or anecdotally include:

• Nausea (very common).
• Flushing.
• Appetite suppression.
• Spontaneous erections/increased libido (can be unwanted).
• Fatigue.
• Darkening of moles/freckles; pigmentation changes.
• Possible increases in blood pressure in some individuals.
• Injection-site irritation.

• Use conservative dosing and slow titration to reduce nausea/flushing.
• Dose at night if fatigue occurs.
• Monitor skin/moles; discontinue and seek evaluation for concerning changes.
• Avoid combining with other agents that raise BP; monitor blood pressure.
• Rotate injection sites and use sterile technique.

• Pregnancy or breastfeeding.
• History of melanoma or dysplastic nevi; high skin-cancer risk (pigment changes can obscure monitoring).
• Uncontrolled hypertension or significant cardiovascular disease (use caution).
• Concurrent PDE5 inhibitors or priapism risk conditions.
• Age <18.

PubMed-linked citations for verification. Many studies are preclinical (animal/in-vitro).

1. Central melanocortin pathways in energy homeostasis and pharmacology of melanocortin agonists. Nat Rev Neurosci. 2006. PMID: 16855563 (doi: 10.1038/nrn2017)
2. Melanocortin receptor agonists and regulation of human pigmentation (review). Pigment Cell Res. PubMed
3. Case reports of melanotan use and adverse pigmentary changes. Br J Dermatol. PubMed