How much vitamin D should you take in winter in the UK?
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The NHS advises everyone in the UK to consider a daily 10 microgram (400 IU) vitamin D supplement in autumn and winter, because from October to late March there is not enough sunlight for your skin to make what you need. Some groups should take it all year. Adults should not take more than 100 micrograms (4,000 IU) a day.
Who should take vitamin D, when, and how much
| Who | When | How much a day |
|---|---|---|
| Most adults and children over 4 | Autumn and winter | 10 micrograms (400 IU) |
| People who are rarely outdoors, such as frail or housebound people | All year | 10 micrograms (400 IU) |
| People living in a care home | All year | 10 micrograms (400 IU) |
| People who cover most of their skin when outdoors | All year | 10 micrograms (400 IU) |
| People with dark skin, for example of African, African-Caribbean or South Asian background | All year | 10 micrograms (400 IU) |
| Children aged 1 to 4 | All year | 10 micrograms (400 IU) |
| Babies under 1 | All year | 8.5 to 10 micrograms; ask your health visitor |
Source: the NHS vitamin D page, checked in October 2026. From late March or early April to the end of September, most people can make the vitamin D they need from sunlight.
Micrograms and IU: how to read a vitamin D label
Labels use either micrograms (µg or mcg) or international units (IU). One microgram is 40 IU.
| Micrograms | IU | What it is |
|---|---|---|
| 10µg | 400 IU | The NHS daily amount for adults in autumn and winter |
| 25µg | 1,000 IU | A common supplement strength |
| 50µg | 2,000 IU | The NHS maximum for children aged 1 to 10 |
| 75µg | 3,000 IU | One capsule of our vitamin D3 and K2 |
| 100µg | 4,000 IU | The NHS maximum for adults and children aged 11 to 17 |
Can you take too much vitamin D?
Yes. The NHS says that taking too much over a long period can cause calcium to build up in the blood, which can weaken the bones and damage the kidneys and the heart. That is why the 100 microgram limit matters.
The easy way to go over it is to take two products that both contain vitamin D. A 75 microgram capsule plus a multivitamin with 25 micrograms is already 100 micrograms. Add up every label before you add another product; our supplement stacking guide shows how.
Can you get enough vitamin D from food?
Some foods contain vitamin D: oily fish such as salmon, sardines, trout, herring and mackerel, red meat, egg yolks, liver, and fortified foods such as some fat spreads and breakfast cereals. The NHS advice to consider a supplement in autumn and winter applies whatever you eat. If you are pregnant, avoid liver.
Why our capsule is 3,000 IU, and who it suits
Our vitamin D3 and K2 gives 75 micrograms (3,000 IU) of vitamin D3 and 100 micrograms of vitamin K2 (MK-7) in one capsule, 90 capsules for £5.99. That is more than the NHS's 10 micrograms and under its 100 microgram adult limit. It suits adults who want a higher daily amount within the limit, in a single capsule a day.
If you only want the NHS's 10 micrograms, choose a 10 microgram product instead; there is no reason to take more than you intend. Our capsule is not for children. If you are pregnant or breastfeeding, follow your midwife or GP. If you take warfarin, speak to your doctor first, because vitamin K affects how warfarin works.
Vitamin D contributes to the maintenance of normal bones and to the normal function of the immune system. Vitamin K contributes to the maintenance of normal bones.
When to take vitamin D
Take it with a meal that contains some fat, at the same time each day. Breakfast or lunch makes it easy to remember. If you take other supplements as well, our stacking guide covers how to fit them into one day.