Lots of spilled vitamins

Can you have too much Vitamin D?

03 Oct 2022


Calculating vitamin D levels

When looking at supplements, the UK guidance is in micrograms (μg). But a lot of the labels refer to IU (International Unit), which can be a bit confusing. To help you out, it’s worth remembering that one IU of vitamin D is equivalent to 0.025 micrograms. So you’ll need to divide by 40 to go from IU to μg. Or you can use this table:⁴


IU How to calculate MCG
400IU Divide by 40 10mcg
600IU Divide by 40 15mcg
800IU Divide by 40 20mcg
1000IU Divide by 40 25mcg
2000IU Divide by 40 50mcg


Vitamin D intake upper level guidance

To help prevent toxicity, it’s advisable to follow the upper intake levels. You shouldn’t consume any more vitamin D than this per day:⁵

Age Intake (IU)
0-6 months 1000
7-12 months 1500
1-3 years 2500
4-8 years 3000
9+ years 4000