123 Farm Organic Rosemary Essential Oil is a very versatile and warming oil that has stimulating effects. Rosemary primarily works on the circulatory system by improving blood circulation, in particular, increased blood circulation to the brain. This is why rosemary has been connected with improved memory, concentration and alertness. Rosemary is often used to treat headaches. It also has stimulating effects on the scalp and hair, possibly treating against hair loss.