Why should I choose Nytol Original ? If you’re a bit tired of sleepless nights and looking for a temporary solution that helps you get to sleep, then Nytol Original 25mg could be right for you. How does Nytol Original work? Let’s get a little sciencey for a second. Nytol Original contains a commonly used antihistamine called diphenhydramine hydrochloride (trust us it’s easier to use than to say!) It works by blocking the normal actions of histamine, the chemical that stimulates arousal-promoting areas of the brain. This helps reduce alertness and promote that first drowsy stage of sleep, helping you to then drift off into a restful, deeper sleep.