You want to start very slowly! Magnesium is a natural laxative so if you take too much, your bowels can't handle it. Start with 1 tablet morning and night.. see how it goes for a few days. Then increase by 1 tablet. I take over 1000mg a day and use magnesium oil. Adding a transdermal magnesium is the best way to quickly reduce your magnesium deficient... so using oral and transdermal. I spray it on my skin and do foot soaks.