Dry hair is hair that lacks some of the normal oil that is found in most hair. This oil, called sebum, comes from the sebaceous glands attached to the hair follicles. Dry hair is not very elastic and tends to break if it's stressed. Dry hair tends to be curly hair, since sebum has a hard time coating it. The best shampoos for dry hair have coconut, jojoba, almond and mineral oils, as well as amino acids and hydrolized proteins as their active ingredients. However, these sorts of shampoos shouldn't be used just before a perm, as they might form a barrier to the treatment.