Each serving of Kalmassure includes 400 mg magnesium citrate. This product is ideal for daytime or night-time use. This product is derived from the most bioavailable form of magnesium, making it easier for your body to absorb and retain. This Kalmassure product is non-GMO, and is free of all major allergens, including gluten and yeast. It is also suitable for vegans and vegetarians.