Fiber queston

Yes Magnesium Citrate is absorbed and helps you build up bone.

Magnesium Oxide helps you poop.

TOO much magnesium oxide and you'll have the runs.

I got magnesium citrate for its laxative effects as well. I did a lot of research and overall this is the info I have "Magnesium is a naturally occurring mineral that is important for many systems in the body, especially the muscles and nerves. Magnesium citrate also increases water in the intestines. Magnesium citrate is used as a laxative to treat occasional constipation."

I also read about magnesium oxide, but opted for the citrate for now.

Who am I to argue with your research!