if u die your hair with kool aid it won't come out until u wash it *edit*That is totally unrelated to the topic.Basically most shampoo formula's are the same, whether you pay £1.99 or £21.99 a...
You can do this by purchasing pH strips or a pH kit to test the balance of each shampoo.Normally you would want your hair to be the same pH as your skin.4 to 5.If you are unable to do that you can...