NOW Magnesium Citrate 400 mg (60 Veg Capsules) is a fully reacted mineral supplement designed to support nervous system health, energy production, and critical enzymatic functions. Magnesium is essential for metabolism, muscle contraction, nerve impulse transmission, and bone mineralization, acting as a required cofactor for over 300 enzymes involved in processes such as fatty acid synthesis, protein synthesis, and glucose metabolism. Adequate magnesium status also helps regulate calcium balance through its effects on the parathyroid gland. This vegetarian/vegan, non-GMO, and kosher-certified supplement is manufactured under GMP quality assurance by a family-owned company since 1968.