How much Vitamin D3 do you need ?

How much Vitamin D3 do you need ?

In an ideal World you should simply get your Vitamin D3 levels tested when you do your Blood tests.. you are looking for 40ng/ml

But since most people will not have their blood tested unless their doctor recommends it. a “recommend” dosage makes sense.. as the place to start

I recommend 5000 IU a day

5000 IU will get at least 97{2658607c068490114260e14c260e6ae174f4b10b752c604f4a58b348bf83bb16} of people above 30 ng/ml.
Will get most people above 40 ng/ml, and close to around 50 ng/ml.
Will not cause anyone to get toxic levels.

For those who want a more careful calculation, 70-80 IU/day/kg of body weight total input is needed to obtain a 25(OH)D of 40 ng/ml.

That works out to about 35 IU/day/pound. So a 100 pound woman would need 3,500 IU/day of total input but a 300 pound lineman would need 10,500 IU/day. Keep in mind this is total input, which includes sunlight, diet and supplements.

Taking all these factors into account, we can conclude a recommendation of 5,000 IU/day is about right for the average adult.