Many Americans suffer from insomnia each year, which can be caused by stress, poor diet, or lack of nutrients like magnesium. While some natural remedies like exercise or avoiding caffeine may help some people sleep, they do not work for everyone. Prescription sleeping pills can also have side effects and do not always leave people feeling refreshed. Taking 400-500 mg of magnesium before bed through supplements may help address the underlying cause of insomnia related to magnesium deficiency and improve sleep without the need for sleeping pills.