Hi
NyQuil contains analgesic, anti-histaminics and sedatives. It may provide relief in mild insomnia, but should be used only occasionally. It induces sleepiness due to the side effect of anti-histamines component.
However, on long term use it has abuse potential and chance of physical dependence. The analgesic component may be harmful for the liver and other organs.
Instead, natural hormonal supplements like melatonin may be tried, which also allow to have a good sleep.
Do write in if you need any other information.
Regards
Follow the instruction for using the Activity Calculator to determine how many calories you burn during sleep while taking NyQuil. The URL to the AC is: http://www.caloriesperhour.com/index_burn.php