TwinLab Magnesium Capsules, 200-Count are an all-natural supplement with a very high potency of 400mg. They can be well-tolerated by many individuals who might be allergic to magnesium. The all-natural magnesium supplement is an essential mineral for calcium and potassium assimilation. It also contributes to the proper nerve muscle impulses, enzyme reactions, formation of bone and carbohydrate metabolism, heart health and PMS. The high-potency magnesium, 400mg contains no artificial colors, flavors or preservatives and no binders, coatings or colorings. Magnesium is an essential mineral for the production of calcium and potassium in the body.