Melanotan is a synthetic hormone that can be used to tan the skin without sun exposure. It works by stimulating melanocytes to produce more melanin, resulting in a darker skin tone within 8-12 weeks. Potential benefits include a natural-looking tan and good UV protection, but it may also cause side effects by affecting other cells and hormones. Overall, while melanotan provides tanning effects like sun exposure, it remains an experimental product with uncertain long term safety.