What vitamin d is good for if every 2 wk?

D3 not D2: If supplementing with vit d, try to get d3 cholecalciferol instead of d2 ergocalciferol. D3 is safer in high doses and has more bioavailability. People have been known to take anywhere from 1000 iu to 10000 iu daily.

Depends on your leve: If you started with a low level and have been loaded with vit d 50000 units on a regimen like once or twice a week , than you need to be maintained on 1000 tp 2000 units a day or 50000 unita a month, so if you are taking every two weeks than 25000 units will be the dose but if your initial level was over 30, you need much less like 400 to 600 units per day. The issue is controversial and we have not.