Bearing that in mind BleeckerSt Girl, what does 12.5mcg cholecalciferol (equivalent to Vit. D3 - 500 IU) translate into? mcg are less that mg aren't they? It's in the 600mg Calcium tablet I was given at the pharmacy. I suspect that it won't be nearly enough to make a difference to my situation, especially when taking the dosages in some of the previous posts into consideration.