This is the one I take. I use it for half of my intake. I used others over the years and kept switching because I was desperate to slow my bone density loss. I did a kitchen counter test one time of 3 different calciums. From then on I've Garden of Life product because it dissolved way faster in the vinegar/water solution than the other two products.(One of the calciums I tested was a calcium citrate and it took quite a while.) I cannot claim that slowing of my bone density loss was due to the change as I changed other things at the same time. I take a high-calcium yogurt (400 mg/8oz) for the balance of my calcium. Pretty good with 1/2 a banana and some walnunts.