Question: are you supposed to leave shampoo in your hair?
Answer: Overall, most shampoos don't need to be left on for a long period. Shampoos work on the surface of the hair and scalp, without soaking in. ... However, that doesn't mean you just slap shampoo on and then rinse it off. You need to rub the shampoo into the scalp to enable those molecules to do their job.