jet lag
"Hi , just wanted to share my melatonin experience after my travel to thailand. 
My jetlag has been really bad for days and of my friends had melatonin pills with him. 
The effect is fast and stronger then a sleeping pill. How can that be possible ? It could be a dangerous thing and becoming a addiction on people. 
I did it 3 times. And I felt super depressed the next mornings.  So I guess something is not right when people are saying.... OH NO WORRIES MELATONIN IS IN YOUR BODY ALREADY. IT IS NOT DANGEROUS."