TRPM8 doesn’t just respond to cold temperatures, though. It also activates in the presence of menthol, a waxy, crystalline organic compound found in peppermint and other mint oils. (It responds to other “cooling agents,” too, like eucalyptol and icilin. Why, exactly, is unknown; menthol just happens to fit the cellular “lock.”)
Read about how this works at mental_floss. Link