Magnesium is arguably the most important mineral in the body, which is why magnesium deficiency can be such an issue. We discuss causes, symptoms of deficiency including: leg cramps, insomnia, muscle pain/fibromyalgia, anxiety, high blood pressure, type 2 diabetes, fatigue, migraine headaches, and osteoporosis. We also discuss people who are at increased risk of magnesium deficiency, and the best supplements to replenish your magnesium levels.