I have consistent problems with sleep & I average 5 to 6 hours of sleep/night...wake up at 3 am and stay awake for 2+ hours...I occasionally take melatonin and each time I find I have severe vertigo the next morning. Sadly, the melatonin DOES help me sleep through the night better than any other remedy (benedryl=restless legs & 5 mg of Zolpidem Tartrate leaves me "hung over" for a day).