Now Foods, Magnesium Citrate, 240 Veg CapsProduct Description Magnesium is a mineral that is critical for energy production and metabolism, muscle contraction, nerve impulse transmission, and bone mineralization.* It is a required cofactor for an estimated 300 enzymes.* Among the reactions catalyzed by these enzymes are fatty acid synthesis, protein synthesis, and glucose metabolism.* Magnesium status is also important for regulation of calcium balance through its effects on the parathyroid