Or conditioner. Hair care products often contain harsh chemicals which can be absorbed and directed into the blood stream. A few years ago I stopped using all commercial hair care products and started using a variety of oils, like coconut and olive oil. The main treatment I use is an apple cider vinegar hair rinse.
Mix equal parts water and organic apple cider vinegar in a squirt bottle. Add 5-10 drops of rosemary essential oil (for dark hair) or chamomile essential oil (for light hair). Spray on dry hair, brush through and rinse. The acidity of the ACV helps balance your hairs pH levels and close the scale like cuticles that coat each hair follicle. Open cuticles promote tangles and frizzy hair, closed cuticles give that glossy look.
*side note if the smell of vinegar offends you, increase the amount of water.