Eases Pain, Disgusts Moths

摘要

Originally derived from a type of laurel tree (Cinnamomum camphora), this waxy aromatic substance has been used as a drug since the Middle Ages, it's absorbed quickly through the skin, where it activates the TRPV3 and TRPV1 nerve receptors, creating a cooling sensation followed by an analgesic-local anesthetic-effect. Camphoris also the active ingredient in Vicks VapoRub and some pest repellents -insects detest the smell. Nowadays, it's synthesized from turpentine oil. An extract of peppermint oil, menthol is often called peppermint camphor because the effects of the two are so similar (menthol triggers the TRPM8 nerve receptors). It adds a bracing, albeit fake, freshness to thousands of products, from cigarettes to mouthwashes to sunburn ointments.