Rosemary oil is known for its ability to improve circulation, particularly when applied topically to the scalp. This increased blood flow stimulates the hair follicles and can lead to faster and healthier hair growth. Clinical studies have shown rosemary oil to be as effective as minoxidil in promoting hair growth without the side effects. Its anti-inflammatory and antifungal properties make it effective in combating scalp issues like dandruff and irritation. Moreover, rosemary oil is known to prevent hair thinning and can even slow down the greying process when used consistently.