Over-the-counter options include diphenhydramine as in Benadryl and doxylamine succinate as in Unisom SleepTabs. Both are thought to have effects on the brain that make it easier for you to fall asleep. During this time, researchers found that participants had fewer symptoms of sleep disorders and improved sleep patterns. When taken in the morning, melatonin can disrupt your normal sleep cycle.
How it works is not well understood. Other results show that insomniacs who only exercise for thirty minutes three or four times a week sleep almost an hour longer than sedentary people and wake up less frequently at night.