Pure Encapsulations Magnesium Glycinate - A highly bioavailable form of magnesium that supports the metabolism of macronutrients and energy production. Magnesium is an essential bone matrix mineral that promotes healthy bone metabolism. Magnesium also plays essential roles in maintaining healthy muscle contractile function. As magnesium regulates calcium channels, it may have an important role in controlling cramping. Several clinical trials have found that magnesium supports muscle function during intense exercise and helps to lessen nighttime leg cramps.