[lambdaba]

Even if it were so (no acute effect, seems unlikely based on, err, anecdata), I've seen claims of it taking up to a year or more to fix a deficiency. It's nt just a nice idea, it actually works. And blood pressure medicine, often diuretics, only worsens magnesium deficiency and thus a magnesium deficiency treated symptomatically with such medicine becomes a chronic hypertensive condition.