Well i don't know about coral calcium, but I use AdvaCal, which is by a company called bioceuticals, basically the product is all natural ingredients which helps it get absorbed easily into the system because it is made up of the same bone make-up. This advanced Calcium is soo clean, it has helped me a great deal after breaking my leg... I healed better, faster and still take it as I do not normally get all the calcium intake I need for my body...
See if AdvaCal is for you, ask you naturopath/doctor = )
To Good Health !!!