Magnesium is essential for more than 300 biochemical processes in the body, including those related to the nervous system and heart function. According to the National Institutes of Health (NIH) Office of Dietary Supplements, magnesium acts as a cofactor for enzymes that generate energy, regulate muscle contractions, and transmit nerve signals. A sufficient daily intake also supports the immune system, helps maintain a regular heart rate, and contributes to stable blood sugar levels, reducing the risk of hypomagnesemia, a condition marked by low magnesium levels in the blood. The recommended daily intake of magnesium varies by age and sex. For adults, the NIH suggests approximately 310 to 320 mg per day for women and 400 to 420 mg for men. When the diet lacks foods such as legumes, nuts, and whole grains—common sources of magnesium—supplements can help meet these requirements. However, the NIH sets an upper limit (UL) of 350 mg per day for magnesium supplements, as higher doses may lead to side effects such as diarrhea and abdominal cramps. Neither the NIH Office of Dietary Supplements nor MedlinePlus specifies an ideal time to take magnesium supplements. The effectiveness of magnesium largely depends on regular use and individual digestive tolerance. Many people prefer to take magnesium with a meal, which can reduce the gastrointestinal discomfort reported by MedlinePlus, particularly with certain forms like magnesium oxide. Others choose to take it in the evening, aligning it with their bedtime routine to help establish a consistent habit and take advantage of its calming effects on the body. The choice of when to take magnesium often comes down to personal preference and how well the body tolerates the supplement. While some may find it easier to incorporate into a morning routine, others may find evening intake more convenient. Regardless of the timing, maintaining a regular schedule is key to ensuring the supplement works effectively and comfortably for the individual.