These are all forms of Vitamin D.
Cholecalciferol and calcifediol are both forms of Vitamin D3, and ergocalciferol is Vitamin D2.
Studies show Vitamin D3 overall, to be the most effective at raising the levels of Vitamin D in the body.
While both cholecalciferol and calcifediol are a version of Vitamin D3, the cholecalciferol is shown to be the most effective in general, with a few exceptions in specific health conditions. In those conditions, a doctor may prescribe calcifediol. Calcifediol is not a supplement, it's actually a drug and is not available over the counter or in supplement form.
Anyone looking to increase their Vitamin D3 levels will receive great benefits by getting adequate exposure to sunlight each day. If this is not a consistent option, taking our Vitamin D3 from cholecalciferol, is a simple way to increase D3 levels in your body, which is proven to be highly absorbable and effective.