Limited research suggests that magnesium aspartate, citrate, lactate, or chloride may be better absorbed than other forms.

Magnesium: Magnesium helps your body absorb calcium by activating vitamin D and influencing parathyroid hormone (PTH) ...

Found naturally in rocks and seawater, there are a number of forms of magnesium, including carbonate, chloride, hydroxide, oxide and sulfate, as well as glycinate, lactate, malate, citrate and ...