Rosemary oil: For the skin: It’s mixed with grapeseed oil or jojoba oil in the proportion 1:10 for oily skin, especially acne-prone skin to absorb excess sebum and to reduce the formation of pimples. For the hair: One of the best essential oils to stimulate hair growth and also to get rid of dandruff. Put 20 drops of the oil on your shampoo to reduce dandruff or mix it with castor oil, eruca sativa oil, or black seed oil in the proportion 1:10 and use it as an oil bath on your scalp to stimulate hair growth.