I was told recently that there are certain shampoos that may make a man not have much endurance during sex. Some doctors claim that if most of the ingredients in shampoos are unnatural, then they could have an effect on a man's sexual performance, which will lead him to experience premature ejaculation.
It was stated that herbal shampoos are better and safer to use than the other ones simply because they don't have a lot of unnatural ingredients, which means that they will provide better nutrients to the hair and scalp--and apparently, to the sex organs.