Certified Naturals Calcium Magnesium Plus K2 - Contains the unique plant-source calcium source known as Aquamin. Aquamin is an award-winning, clinically studied ingredient sourced from the Icelandic red-algae Lithothamnion calcareum. Aquamin contains a complex of 74 minerals including calcium and magnesium making it an ideal supplement for bone health. Calcium intake, when combined with sufficient Vitamin D, a healthy diet and regular exercise may reduce the risk of developing osteoporosis. Also contains added magnesium, potassium, boron, zinc and important bone vitamins D3 and K2.