Cabot Health Magnesium helps to relax and calm the nervous system. Stress depletes magnesium stores in the body, making us more susceptible to stress, through a vicious cycle of stress and magnesium depletion. Magnesium supplementation can help to relieve headaches. Many people experience relief from their cramps when supplementing with magnesium. As magnesium helps to calm the nervous system, it is a great supplement to take before bed to help reduce stress and evoke relaxation. Stress is one of the most common causes of a poor night's sleep, so helping to reduce stress could be beneficial for a restful sleep.