Nature Made
amazon. com
$10. 99
“Calcium is best absorbed in doses of 500 milligrams or less, ” says Passerrello. That’s because the higher the elemental calcium (percentage of calcium by weight), the more difficult it is for the body to absorb, per the NIH. This dose from Nature Made is USP-certified calcium carbonate and also contains vitamin D3 , which aids in absorption, Passerrello adds.