Magnesium deficiency can occur due to low intake, poor absorption, or increased losses through the kidneys. Symptoms can range from nonspecific issues—muscle cramps or twitches, irritability, poor sleep, fatigue, and low appetite—to more serious neuromuscular or cardiac rhythm concerns in severe cases. Importantly, these symptoms are not unique to magnesium: iron/B12 deficiency, thyroid problems, stress, sleep deprivation, and certain medications can look similar. Serum magnesium is commonly checked, but it does not always perfectly reflect total body stores, so clinical context and risk factors matter. Diabetes, older age, gastrointestinal disorders, alcohol use, and some diuretics can increase the risk of inadequate magnesium. For persistent symptoms, it’s safer to evaluate the cause rather than self-prescribing high doses.