Diane, I suppose if you "google" it so to speak, you'll find out HOW it works...I can only say that as a shiftworker (and overseas traveller!), I use melatonin quite a bit - probably 7 times a month. It's hard to go to bed at 0700 and sleep until 1300 hrs...I have to do that regularly, and melatonin helps. I remember reading years ago about it, and "how" it works...not I forget the "how" - sorry! But I do use it, as do several of my flight attendant friends, and for me, it does work! Good luck.

Charlene

P.S. Never use over 3mg, the 5mg was proven dangerous