Vitamin D is not a single chemical but rather a group of related compounds: ergocalciferol (vitamin D2), a 1:1 mixture of ergocalciferol and lumisterol (vitamin D1), cholecalciferol (vitamin D3), 22-dihydroergocalciferol (vitamin D4) and sitocalciferol (vitamin D5). When these compounds reach the liver they are converted to the prohormone calcidiol and then to calcitriol by both … Continue reading Vitamin D is not a vitamin