IU and µg: how to convert
Vitamin D is labelled in two units. EU nutrition tables use micrograms (µg), while the front of the pack often shows international units (IU). The conversion is fixed: 1 µg of vitamin D equals 40 IU.
| IU | µg | % of NRV (5 µg) |
|---|---|---|
| 400 IU | 10 µg | 200% |
| 1000 IU | 25 µg | 500% |
| 2000 IU | 50 µg | 1000% |
| 4000 IU | 100 µg | 2000% |
The EU nutrient reference value for vitamin D is 5 µg (200 IU), set in Annex XIII of Regulation (EU) No 1169/2011. That is why vitamin D labels show percentages in the hundreds or thousands.
Which vitamin D to choose: D3, D3 + K2 or vegan D3
Every product here contains the same form of vitamin D, cholecalciferol (D3). What differs is the format and what else is in the dose.
| Product | What is in it | What to check on the label |
|---|---|---|
| D3 softgel | D3 dissolved in oil | µg per softgel and the type of oil |
| D3 tablet | D3 with fillers, often with K2 or minerals | the % NRV of each nutrient |
| D3 + K2 MK-7 | D3 plus, usually, 100 µg of K2 | the amount of both vitamins per daily dose |
| Vegan D3 | D3 from lichen instead of lanolin | whether the capsule shell is gelatin-free |
In D3 + K2 products the vitamin K2 is menaquinone-7 (MK-7). The usual 100 µg is 133% of the 75 µg NRV for vitamin K. Some combinations also contain calcium, vitamin C or zinc; each nutrient then has its own line on the label. Vegan D3 is the same cholecalciferol as lanolin D3; only the raw material differs.
Reading the dose
Check three things on the label: the amount of vitamin D per daily dose in µg, the number of softgels or tablets that make up that dose, and how many days the pack lasts. If you take more than one product with vitamin D, for example an omega-3 with D3, add the amounts together and stay within the daily doses given on the labels. We calculate the price per day from the daily dose on the label, so a pack that looks cheap but needs two softgels a day is shown at its real cost.
EU health claims for vitamin D
Regulation (EU) No 432/2012 permits these statements for products that provide at least 15% of the NRV per daily dose:
- Vitamin D contributes to the maintenance of normal bones.
- Vitamin D contributes to the maintenance of normal teeth.
- Vitamin D contributes to the maintenance of normal muscle function.
- Vitamin D contributes to the normal function of the immune system.
Questions
Is vitamin D the same as D3?
Vitamin D is the group name. D3 (cholecalciferol) is the form used in all the products in this category.
When should I take vitamin D?
Vitamin D is fat-soluble. The NIH Office of Dietary Supplements notes that fat in the gut improves its absorption, although some is absorbed without it. The simplest routine is to take the softgel or tablet with a meal that contains some fat. There is no set time of day, so pick the meal you never skip.
Can children take vitamin D?
Our range is softgels and tablets with 1000 to 4000 IU. Before giving one to a child, read the label: it states the age the product is meant for. NIH ODS lists these upper limits for vitamin D: 63 µg (2500 IU) at 1 to 3 years, 75 µg (3000 IU) at 4 to 8 years and 100 µg (4000 IU) from 9 years. For babies and small children, agree the dose and the format, usually drops, with a doctor.
Is 4000 IU a lot?
4000 IU is 100 µg, or 2000% of the EU NRV. NIH ODS gives this amount as the upper limit for adults and for children from 9 years. Take no more than the daily dose stated on the label. All products with 4000 IU per dose are collected on a separate page: vitamin D 4000 IU.
Softgel or tablet?
Softgels hold D3 in oil. Tablets usually combine D3 with K2 or minerals. The vitamin D amount is printed on both, so compare by µg and price per day.
Sources
- Regulation (EU) No 1169/2011, Annex XIII (reference intakes)
- Regulation (EU) No 432/2012 (permitted health claims)
- NIH Office of Dietary Supplements: Vitamin D fact sheet
- EFSA: Health claims
Content reviewed by Inese Kalniņa, dietitian.
2026-08-27
