The form of magnesium matters
Magnesium supplements are often compounded with a salt, an acid, or an amino acid chelate to make the magnesium stable and suitable for consumption. In the bottle, Natural Vitality CALM contains magnesium carbonate and citric acid. When combined with water, a chemical reaction takes place and the two bind together to become magnesium citrate. Because it’s dissolved in water, Natural Vitality CALM has advantages over pills or capsules, as it is an alternative form of magnesium supplementation. It’s this dissolution that ionizes magnesium and may enhance absorption.
Table by Dr. Crisafi Comparing Bioavailability of Magnesium Forms Source: Daniel J Crisafi, NDA, MH, PhD