I'd still encourage others to try since bodies react differently to the active ingredients in these over-the-counter sleep aids. It has magnesium, L-theanine, glycine (amino acid), and inositol (B vitamin that helps with regulating body function). It stays in your system longer than other sleep medications, so it’s more likely to cause that next morning “hangover” feeling of lingering drowsiness. It stays in your system longer than other sleep medications, so it’s more likely to cause that next morning “hangover” feeling of lingering drowsiness. , used in OTC medications like Benadryl and ZzzQuil, is also one of the most common OTC sleep medications and can be used for allergies too.