Valerian is one of the most common sleep remedies for insomnia. Numerous studies have found that valerian improves deep sleep, speed of falling asleep, and overall quality of sleep. However, it's most effective when used over a longer period of time. Keep in mind that about 10 percent of the people who use it actually feel energized, which may keep them awake. If that happens to you, take valerian during the day. Otherwise, take 200 to 800 milligrams before bed.