Magnesium Glycinate (Biglycinate) is a form of magnesium where the magnesium molecule is bound to the amino acid glycine. This makes magnesium glycinate one of the best absorbed forms of magnesium. The most common form of Magnesium is magnesium oxide with an absorption rate of less than 4%. Magnesium glycinate is different because much less water is able to latch to the magnesium and side effects such as diarrhea are far less common. Double Wood Supplements' Magnesium Glycinate product is manufactured and tested in the USA from Globally Sourced Ingredients, Vegan Safe, Non-GMO, and Gluten Free. Each bottle contains 180 capsules with 400mg of Magnesium Glycinate each, which is nearly a half year supply.