Melanocortin Peptides Anti-aging Weight Loss Not approved

Melanotan II

Also known as: MT-II, MT2, Melanotan 2

Melanotan II (MT-II) is a cyclic synthetic analogue of alpha-melanocyte-stimulating hormone (α-MSH). It acts as a non-selective agonist on multiple melanocortin receptors (MC1R, MC3R, MC4R, MC5R), producing tanning, appetite reduction, and sexual response stimulation. It should not be confused with Melanotan I (afamelanotide), which has medical approval.

Mechanism of action

MC1R: Stimulates melanogenesis (melanin production) → tanning without UV exposure
MC3R/MC4R: Appetite reduction, central sexual stimulation
MC4R: Spontaneous erection (priapism in some cases)

Uses & indications

Cosmetic tanning without sun exposure (most common use)
Erectile dysfunction (off-label; research)

Effects

Effects: Significant tanning (2–4 weeks), appetite suppression, increased sexual desire.

Adverse effects (frequent and significant): Intense nausea, facial flushing, priapism (involuntary spontaneous erections), changes in nevi (moles) → risk of malignant transformation, irregular hyperpigmentation, fatigue. Melanoma risk not ruled out.

Considerations & contraindications

WARNING: Changes in moles may indicate malignant transformation; strictly monitor
Not approved in any country for these indications
Risk of priapism requiring urgent medical attention
Do not use in persons with history of melanoma or dysplastic nevi

Regulatory approval

Not approved in any country. Illegal for public sale in the EU, UK, and Australia. In the USA, it can only be sold as a research peptide, not for human consumption.

Dosage

Loading protocol: 0.25 mg/day sc (low initial dose to tolerate nausea) → up to 0.5–1 mg/day. Solar/UVB exposure enhances the effect.

Storage

Lyophilized: −20°C. Reconstituted: 4°C, use within 4 weeks. VERY light sensitive.

Technical data

Regulatory status Not approved

Molecular weight 1024.19 Da

Half-life ~1–2 h

Administration routes Subcutánea