Make your own, for mere pennies: Baking soda reduces oily hair and cleans up product build up, though the smell is thoroughly utilitarian. Mix 1/4 to 1/2 cup (more for longer hair) of baking soda with water to make a thick paste. Put the paste on wet hair and scrub into roots/focusing on the more greasy areas. Scrub in and leave in for 5 minutes, then rinse.