Natural Factors Stress-Relax Magnesium Citrate Powder - Berry Flavour - An effective way to meet your body’s daily magnesium requirement. Involved in energy production inside every cell, and magnesium supplementation has been shown to improve endurance during exercise. Magnesium also plays an important role in the central nervous system, regulating neurotransmitter metabolism and modulating the sensitivity of nerve receptors, including those involved in the “fight or flight” stress response. Research shows that taking a supplement can quickly restore healthy levels of magnesium, relieve anxiety and other symptoms associated with deficiency, and lower the risk of serious conditions such as heart disease.