Hypomagnesemia means having low levels of magnesium in the blood, which is an important mineral for health. The body usually has about 25 grams of magnesium, mostly in bones and soft tissues, with only 1% in the blood. If blood magnesium levels drop below 0.75 mmol/L, it is considered low. Causes include insufficient intake of magnesium, excessive loss through kidneys or intestines, and certain medications. High-risk groups include hospitalized patients, people with diabetes, and those who overuse alcohol. Symptoms include muscle cramps, fatigue, and irregular heartbeats. Doctors may suspect it if blood calcium and potassium levels are also low. Treatment involves intravenous magnesium for severe cases, and oral supplements for follow-up. For mild cases, dietary changes may be enough. Foods rich in magnesium include nuts, seeds, beans, and whole grains. It's important not to exceed the supplement upper limit of 350 mg per day. Untreated hypomagnesemia can lead to serious heart problems like arrhythmia.