Although there is no evidence that castor oil can stimulate hair growth, you can apply it to your hair by massaging the oil directly into your scalp, suggests Healthline. This process requires castor oil, rubber gloves, an applicator brush, an old T-shirt and a shower cap.
Apply castor oil to your hair by first wearing old clothes that you don't mind getting soiled, advises Healthline. Next, prepare your hair by dividing it into sections so that the scalp is exposed. Don rubber gloves, and apply the oil to the scalp using a small brush. Work the oil evenly over your head, and brush it through your hair with a comb. Tuck your hair up into a shower cap, and leave it on for up to two hours. Wash out the oil, and shampoo and condition the hair.
Castor oil is often used to treat hair loss or grow longer hair faster, but its main purpose is as a laxative, says Healthline. It can also moisturize dry skin or treat dermatosis. Because it is a natural antiviral and antimicrobial, it also works when clearing up fungal infections. Some people claim that castor oil can make hair grow up to five times the average rate of almost 1/2 inch per month, but no hard proof exists.