My General rule of thumb for my DIY hair and body products follows the Ayurvedic tradition: never put anything on your body that you couldn’t also eat.
I made a hair mask consisting of organic coconut oil, organic raw neem honey, and cinnamon. For the length of my hair I used about four tablespoons of coconut oil, one teaspoon of honey and one teaspoon of cinnamon. Once mixed, apply to hair, from scalp to ends, massaging in well as you go. Wrap hair in towel or shower cap and let sit for 2 or more hours.
It may take two shampoos to get the mask out, and I find using a conditioner after shampooing also removes any residual hair mask. My hair is conditioned, as well as shiny and thicker after this hair mask.