Rosemary essential oil is distilled from the leaves of the Rosemary bush and is part of the mint family. It is a fresh woodsy middle note with a hint of camphor. It is most well known for its ability to stimulate hair follicles and is therefore often used in shampoos and alopecia blends. It is quite a stimulating oil and helps increase consentration so is a good oil to diffuse during late night studying sessions. It has been proven to decrease the levels of Cortisol in the blood which causes stress and send the body into "fight or flight" response.