Maps, mg oxide is so poorly absorbed that it is almost useless, don't know about the malate except I really don't like the taste. Albion process mg glycinate is well absorbed, least likely to increase toilet time, and tastes OK.
I fixed a severe back injury of long duration (28 years) with the raw zero carbohydrate diet, but that's probably not your problem. For that last 4 years I've had lower back ache on rising in the morning and disappearing in 1/2 hour, aggravated a lot two weeks ago Saturday while changing from winter to summer tires and changing rear brake pads. Decreasing slowly.
It hurts every time I stand up, and makes me walk with baby steps. Legs seem weak. Pain is at the top of the pelvic bone, mostly on the right side.
Taking breaks from Iodine has no effect.
I'm wondering if it's time for magnetic therapy.