I've found that it works to counteract my insomnia, at least in the sublingual form. The slow-dissolving melatonin is a nice contrast to other sleep aids because it doesn't try to knock me out; it's more like a massage than a blow to the head. However, the crappy/crabby feeling the next morning is serious enough to make me avoid melatonin most of the time. Generally speaking, I'd rather have insomnia than take some of the unpleasant medication designed to attack my brain. It bothers my wife more than it bothers me. If worst comes to worst, a prescription anti-anxiety pill does the trick.

This didn't work for me at all and made me feel very groggy and parched in the morning.  Although, I should add that I have a pretty obscure sleep disorder (Delayed Sleep Phase Syndrome) and most sleeping pills do not work for me.  If you have reoccurring sleep issues, I strongly recommend seeing a doctor about it.  I wish I had sooner.

On top of helping me fall and stay asleep, melatonin has great anti-oxidant properties and is even believed to slow down the aging process somewhat. The only reason I gave it a 4 instead of a 5 is because it can put me in a depressed mood sometimes.