I've not tried magnesium as a stand-alone supplement. I've read that it can decrease the absorption of alendronate if they're taken too close together so I've been wary to try it (though with the alendronate being taken in the morning once a week I doubt it would cause problems). I do take a multi-vitamin every evening that contains 100 mg of magnesium and I try to get a good amount through foods -- lentils, dark chocolate, spinach, etc.

Do you take magnesium yourself and if so what dosage?