Magnesium is a mineral that acts as a cofactor in over 300 enzyme systems in the body regulating processes like protein synthesis, muscle and nerve function, blood glucose control, and blood pressure. It is required for processes like DNA, RNA, and glutathione synthesis and helps transport calcium and potassium ions across cell membranes. Adults contain around 25g of magnesium on average and intake levels are important as habitual low levels can increase illness risk over time. Good dietary sources include green leafy vegetables, legumes, nuts, seeds, and whole grains.