First of all, let's back up. What is melatonin? It's the hormone your brain produces naturally as part of its circadian rhythm, or the internal clock your body has to keep you on a natural, daily sleep schedule. Your pineal gland is in charge of making it, and sunlight signals it to slow down production so you can wake up and go about your day. Though your brain is already producing melatonin, the idea of taking a supplement is that it jump-starts your sleep cycle.
The product, advertised as a natural sleep aid for children, has raised serious safety concerns because it allegedly contains significant levels of melatonin, a prescription-only drug.