Carrier oils are plant-based oils used to dilute essential oils before applying them to the skin or hair. The "best carrier oil for hair" is one that is rich in nutrients and has properties that benefit hair health. For example, coconut oil is a popular carrier oil for hair because it is high in lauric acid, which has been shown to penetrate the hair shaft and provide moisture.
Carrier oils have been used for centuries to care for hair. The ancient Egyptians used castor oil to promote hair growth, while the Romans used olive oil to condition their hair. Today, carrier oils are still widely used for a variety of hair care purposes, including moisturizing, conditioning, and promoting growth.