There are about 70.8mg of magnesium in one serving of gummies. Magnesium Gummies 600mg per Serving contains 400mg Magnesium Glycinate and 200mg Magnesium L-Threonate. Usually, magnesium glycinate contains about 14% magnesium, and L magnesium L-threonate contains about 8%,so there are about 70.8mg of magnesium in one serving of gummies.