My mom used to mix castor oil into whatever grease she used on me and my sister's hair when we were younger, and she swears that's what made our hair grow long, but I don't know for sure, obviously. Now, I mix it with my other essential oils (jojoba, olive, rosemary, coconut) to apply to my hair. It's too sticky to apply alone. I guess it works well; I've got no complaints. It's supposed to thicken the hair though.