When determining a vitamin D dosage that's right for you, we should consider how much our bodies would make naturally when given the right conditions.
A healthy, light-skinned individual makes at least 10,000 IU after about 30 minutes of full-body sun exposure.
But it needs to be the right kind of sun exposure.
The tilt of the earth's axis determines how much (if any) vitamin D our skin can make.
For most of us living in the U.S., our skin can only make appreciable amounts of vitamin D during the warmer months.
This is part of the reason why it is so easy to become vitamin D deficient. That and the fact that most of us either actively avoid the sun and/or spend the vast majority of our time indoors.
Getting your vitamin D levels checked is incredibly important if you are serious about being healthy.
Once you know how deficient you are, you will be better able to take the right dosage for you.
Just make sure that you take natural vitamin D instead of the synthetic vitamin D2 your doctor is likely to prescribe.
The Vitamin D Council recommends the following for those who get little UVB exposure:
After 2 or 3 months have your blood levels checked. If you don't want to go to the doctor, you can order a test online (see my vitamin D testing page).
Odds are good that you will have to increase your vitamin D dosage if:
The goal is to get your levels between 50-100 ng/ml (125-250 nmol/L) year round.
Vitamin D testing generally needs to be done several times before you figure out how much your body needs every day.
And please don't worry about vitamin D overdose.
When we take this supplement at doses nature intended, there is no risk of toxicity.
And there have never been any published reports showing that doses of 10,000 IU per day were toxic.
Just make sure you are taking the natural vitamin D3 (cholecalciferol). The toxicity reports physicians like to point to are from the synthetic vitamin D-like drug D2 (ergocalciferol).