i literally grew up on melatonin because from the age of like 9 i was an insomniac. i stopped using it for about the past 2 years bc i was getting like.. an immunity to it. however, now i don't need to take it as often, but when i do, it works just as well as it did in the beginning. i love it. and it's not scary cus' it's not chemical, it's a natural thing.