Summary of Acceptable Vitamin D Levels - Open Main Website

The following 25(OH)D blood serum levels are now generally accepted:

Blood levels below 20 ng/ml or 50 nMol/L constitute a serious deficiency
Blood levels above 32 ng/ml or 80 nMol/L had previously been considered acceptable

Blood levels of 40 ng/ml or 100 nMol/L are now considered the lowest acceptable level
Blood levels of 60 ng/ml or 150 nMol/L are now considered an optimum level
Blood levels of 80 ng/ml or 200 nMol/L are now considered a safe upper limit

Blood levels above 100 ng/ml or 250 nMol/L are not considered healthy
Blood levels above 150 ng/ml or 375 nMol/L will cause toxicity

Once your 25(OH)D blood serum level is known it is then possible to estimate
the minimum amount of Vitamin D3 supplementation required to raise
your blood levels to a more acceptable level.

Trials have shown that an average adult (taking Vitamin D3 by mouth)
requires at least the following levels of supplementation to raise
their blood levels by the stated amounts:

Daily Vitamin D3
supplement level

Raises blood level
of 25(OH)D by a
maximum of:


1000 IU

10 ng/ml or 25 nMol/L

2000 IU

20 ng/ml or 50 nMol/L

4000 IU

40 ng/ml or 100 nMol/L

5000 IU

50 ng/ml or 125 nMol/L

Grassroots Health FAQ
Grassroots Health - Dose Calculator