Herbal Henna Powder Black Mehndi For Hair Conditioner this is the best henna for hair conditioner. The color of the hair is black, but not too dark. It also provides softness and shine to your hair, which makes it look beautiful. It works by depositing a layer of pigment on your hair that locks in moisture and helps prevent frizz. It also promotes healthy-looking hair by adding hydration and nourishment without weighing it down.