Recently, the unregulated use of untested synthetic alpha-melanocyte-stimulating hormone (α-MSH) analogues, commonly known as melanotan I and II, appears to have increased. These analogues are primarily used for their tan-stimulating effects. Dermatologists see many patients in their clinic who tan. This review provides an overview of the risks of the unregulated use of these substances. Other topics discussed here include the history and safety of afamelanotide, which is the only α-MSH analogue that is approved for use in a limited number of medical indications. Although afamelanotide has been thoroughly tested and deemed safe, illegal melanotans are likely risky for several reasons. There are questions regarding the preparation, administration, and dosage of these substances. In addition to these general risks, increasing numbers of case reports indicate that the unregulated use of both melanotan I and II is associated with cutaneous complications, particularly melanocytic changes in existing moles and newly emerging (dysplastic) nevi. Four case reports have described melanomas emerging from existing moles either during or shortly after the use of melanotan. Although conclusive evidence linking these phenomena is lacking, publications have stressed the importance of awareness that melanotan is a part of a 'tanning culture' in certain subpopulations. Multiple national health organizations have issued safety warnings regarding the use of melanotan I and II.