Imagine just wanting to be jacked and tan and you end up like this? Melanotan II is a peptide that increases the melanin in your skin and can give men a boner that Melanotan II is a synthetic peptide that mimics the bodys natural melanocortin hormones, primarily activating receptors involved in skin pigmentation, appetite, and central nervous system signaling. MELANOTAN 2 (10ml 20mg) peptide to stimulate melanin synthesis. Melanotan 2 Dosage Calculator and Chart A Z Guide