@0:32, OMG....she really doesn't know the basic molecular level of vitamins. D2 and D3 are from different natural sources!! D2 is from plants and D3 is from human and animals. How come you said that from D2 converted to D3 in human body?? Both D2 and D3 are active form already which are produced via light absorption (UV for D3 I learned) from their proactive forms.