Overview
Melanotan II is a synthetic melanocortin-receptor agonist marketed online for skin tanning (and, secondarily, effects on libido). It is one of the more safety-scrutinized peptides sold to consumers.
How It's Thought to Work
It stimulates melanocortin receptors, increasing melanin production (darker skin) and also affecting appetite and sexual arousal pathways.
What the Research Says
Human data is limited and regulators have repeatedly warned against it. It is related to approved melanocortin drugs but is itself unapproved for consumer use.
Regulatory & Legal Status
Not approved by the FDA. Multiple health agencies (including the UK's MHRA and FDA) have issued warnings against buying or using it.
Safety Considerations
Reported concerns include nausea, blood-pressure changes, and changes to moles/pigmentation. Regulators advise against use. Consult a qualified clinician.