Are you looking at the elemental Mg content, or the weight of the Mg, the malate, and any possible waters of hydration? I suspect it's the later. The standard is to report micronutrients as elemental, but occasionally some flakey outfit will do it the other way, which might make the pill seem "stronger" to the typical consumer.
I was actually looking at the front label.
I just bought some Magnesium Malate from Source naturals and I think I have an understanding of what the label is saying.
The front label says 1250 mgs right?
The back label apparently says that this is the amount found in the malic acid (as mag malate).
It's a little confusing, but I 'think' the magnesium dose is actually 425 mgs.
Supplement Facts
Serving Size 3 Tablets
Servings Per Container 60
Amount Per Serving
%Daily Value
Calories
10
Total Carbohydrate
3 g
1%*
Magnesium (as magnesium malate)
425 mg
106%
Sodium
5 mg
<1%
Malic acid (as magnesium malate
and malic acid)
2.5 g
†
*Percent Daily Values (%DV) are based on a 2,000 calorie diet.
†Daily Value not established.