okay well i looked that brand up to find out the form, and you'll have to confirm but from what i can tell the label says it's magnesium oxide.
sooo, that is the least absorbable form. but i would not recommend taking 2 or 3 per day because you'll be stuck in the bathroom all day.
however, it does do the trick. you just have to pay with the runs.
magnesium citrate is a little better.
magnesium glycinate does not give the runs, but i have found it critical to take the pill before a solid meal because otherwise it relaxes my lower oesophageal sphincter resulting in an unpleasant cough (my version of heartburn apparently)
personally i make a determined effort to eat healthy magnesium-rich foods as often as possible.
hope that helps!
my approach: no meds so far - just nutrient-dense anti-inflammatory whole foods, and supplements where needed
info: www.whfoods.com, www.nutritiondata.com