I am going to assume it is Not Chelated because it does not have the word Chelated on the box. I am not sure about posting a link here so do not want to violate any rules but the name of the product is MagOx 400. The box reads: Most Concentrated Form of Magnesium* Serving Size is 2 Tablets and one serving equals 482.6 mg which they state is 121% of the RDA?? If it causes loose bowels (sorry tmi) or stomach issues I am not so sure I want to take it. Because that was one reason I went Gluten Free as I had that issue daily, every time I ate. Since I began eating this way I have not had one single solitary episode, everything seems to have regulated itself to normal. I have not been that way in years, I am afraid to take something if it is gonna upset my stomach like that. Any thoughts?