Calcium, magnesium, and vitamin D are each essential for healthy bone formation.* Calcium and vitamin D support bone mineral density while magnesium supports bone strength and remodeling.* Cal-Mag 2:1 Plus D supplies calcium citrate, a highly absorbable, well-tolerated source of calcium, balanced with magnesium in a 2:1 ratio. Magnesium bisglycinate chelate from Albion Laboratories provides highly absorbable magnesium that is unusually well-tolerated without GI side effects. Natural vitamin D3 assists calcium absorption to enhance benefits for bone health.* May be used with MultiThera multiple vitamin/mineral supplements to augment calcium, magnesium, and vitamin D intake when necessary.