Magnesium is a cofactor in many enzyme systems, especially those related to energy production and protein synthesis. Helps eliminate ammonia from the body, is important for regulating heart rate, muscle contraction and neurotransmission. Low magnesium levels have been found in people with heart disease. High strength magnesium citrate. The citrate form provides higher magnesium absorption. Especially useful in athletes for the treatment of cramps and in people with low stomach acidity. On tablets.