MG stands for milligram, which is a unit used to measure mass. It is one-thousandth (0.001) of a gram and can be written as mg or Mg if referring to the chemical element magnesium.
Hair loss may occur when you switch supplements depending on the amount of mg of each ingredient in the stack, but I did not experience that. (acnesupplementscritic.com)
Studies show more than 400 mg per day can put a person at risk of adverse effects. (inc.com)
They also have no cholesterol and are low in salt, with only 4 mg sodium per cup. (farmerdirect.coop)