Also known as eucalyptol, it’s a cyclic ether and a monoterpenoid found in a variety of essential oils, including eucalyptus, camphor, peppermint, and more. It’s considered a thermoreceptor agonist – in other words, it makes our skin feel hot or cold even though there’s been no change in temperature. It reacts with a temperature transient receptor (TRPM8) that we find on our skin and in the nasal vestibule (aka our nose) to make it feel colder.