Dietary Supplement Mg True Elemental Content Support for Muscle and Heart Function Purity & Potency Guaranteed Natural Factors Magnesium Citrate is in an easy-to-swallow capsule. The citrate form is extremely well absorbed and well-tolerated by the body and is necessary for hundreds of enzyme reactions in the body and for normal heart function. It is necessary for protein synthesis, carbohydrate metabolism, proper muscle function and helps to absorb calcium and potassium. All Natural Factors products are manufactured in accordance with the Government of Canada's Good Manufacturing Practices (GMP), among the highest standards in the world.