There are at least four types of magnesium on sale. The malate version was my choice after I found out the Holland & Barrett version that I had purchased was the least effective. Like every thing else a Google search is helpful.
I can't actually remember exactly why... but I remember looking up the different types and noticing that once was basically a laxative, and the others had different amounts of absorption, and I ended up going for the chelated.
I can't actually remember exactly why... but I remember looking up the different types and noticing that once was basically a laxative, and the others had different amounts of absorption, and I ended up going for the chelated.