Castor oil can help moisturise the scalp and may reduce hair breakage, but there is no strong evidence that it significantly increases hair growth. Applying it to the scalp will not increase hair growth elsewhere on the body.

Castor oil can help moisturise dry hair and may reduce further splitting by making the hair shaft more flexible. However, it cannot repair split ends once they have formed because the hair shaft is physically damaged. The only effective treatment for split ends is trimming the damaged hair, while oils can help protect the hair and prevent further damage.