Muscle twitching is typically due to a magnesium deficiency. I used to think that calcium should also be supplemented, however for many people a deficiency in magnesium might be a deficiency in magnesium relative to calcium, and taking large amounts of calcium and magnesium supplements just makes this worse. now I realize that those with mercury toxicity might be better off either taking no calcium supplements if their diet has plenty of calcium, or else taking calcium and magnesium in a 1:1 ratio(or perhaps less calcium than magnesium?), and not the 2:1 calcium to magnesium ratio that many supplements have.

I also realized that my diet is low in sodium and high in potassium. Those who eat many natural or minimally processed foods and forget to add salt may be sodium deficient.