Hair oils and curly hair: hydrating without promising growth

Hair that breaks less may appear to grow faster, even if the follicles are not working harder. This is the nuance to keep in mind regarding castor, coconut, argan, or olive oils, which are often touted as growth accelerators in hair care routines.

A systematic review published in the Journal of Drugs in Dermatology on coconut, castor, and argan oils found the strongest evidence for coconut oil regarding fiber quality, particularly for brittle hair. However, it concluded that there is limited evidence for hair growth and did not find strong support for castor oil as a means to promote hair growth.

Research on hair fiber primarily highlights a protective effect. Coconut oil can penetrate the hair and reduce some porosity and damage associated with washing, helping lengths to withstand better. Preserving inches that would have broken can create a clearer impression of progress, but this is not the same as accelerating growth at the root.

For curly, coily, or frizzy hair, which is often more prone to dryness and breakage, oil works better as a care supplement than as a growth product. The American Academy of Dermatology first recommends using a conditioner on the lengths and gentle detangling, followed by a small amount of oil on areas that are still dry or frizzy.

Quantity matters. A very thick oil or one applied in excess can leave residues, weigh down the hair, and complicate washing. The AAD advises focusing shampoo on the scalp to remove excess sebum, dead skin, and product buildup without unnecessarily drying the lengths.

On the ends or still damp lengths, oils are primarily used in small amounts to provide slip and shine. According to the AAD, a small amount of oil like argan can complement a leave-in treatment when hair remains dry or frizzy, avoiding overload on the scalp.