How much vitamin D per day? UK guidance and safe limits

How much vitamin D do you need per day?

The UK recommendation is 10 micrograms (400 IU) a day for everyone from the age of 1 – including pregnant and breastfeeding women, older people and anyone at risk of low vitamin D. Babies under 1 need 8.5 to 10 micrograms a day.

Unlike some countries, the UK does not set a higher figure for older adults – 10 micrograms applies at every age from 1 upwards.

How much vitamin D should I take in winter in the UK?

Between October and early March the sun isn’t strong enough for your skin to make vitamin D, and it’s hard to get 10 micrograms from food alone. So the NHS says everyone should consider a daily supplement containing 10 micrograms during autumn and winter.

From late March or early April to the end of September most people make enough from sunlight, and you may choose to stop. The exception is people who get little or no sun on their skin – those who are housebound, live in a care home or usually cover up outdoors – who are advised to take 10 micrograms all year. People with dark skin should consider doing the same.

Why do other countries recommend different amounts?

Each country sets its own figure from the same evidence, using slightly different methods. You may see these online:

The differences are smaller than they look: all of them sit between 5 and 20 micrograms, and all of them are well below the upper limit of 100 micrograms.

How do you convert micrograms to IU?

1 microgram (µg or mcg) of vitamin D = 40 IU. To get IU, multiply micrograms by 40; to get micrograms, divide IU by 40.

How much vitamin D can you safely take every day?

The NHS says adults – including pregnant and breastfeeding women and older people – and children aged 11 to 17 should not take more than 100 micrograms (4,000 IU) a day. Children aged 1 to 10 should not have more than 50 micrograms (2,000 IU), and babies under 12 months no more than 25 micrograms (1,000 IU). For adults and children aged 1 to 17, these match the limits the European Food Safety Authority confirmed in 2023.

The limit covers all supplements added together – a vitamin D tablet, a multivitamin and fish liver oil all count. Some medical conditions mean you can’t safely take as much, so if your doctor has advised a different amount, follow their advice. More in Can you take too much vitamin D?

Is 2000 IU of vitamin D3 too much?

Not for a healthy adult. 2,000 IU is 50 micrograms – five times the UK recommendation, and half the adult upper limit. It’s more than most people need, and the NHS says 10 micrograms is enough for most, but it leaves a wide margin below 100 micrograms.

It is too much for young children: 50 micrograms is the full daily limit for ages 1 to 10, so adult-strength tablets aren’t meant for them.

What strengths do vitamin D supplements come in?

Most range from 10 micrograms (400 IU) to 100 micrograms (4,000 IU). Higher strengths are popular because one small tablet covers your intake with room to spare, but a higher number is not better in itself – the aim is to stay comfortably within the limit.

Our everyday vitamin D3 provides 50 µg (2,000 IU) in one small vegetarian tablet: five times the UK reference intake and below the 100 µg upper limit. A pouch of 365 tablets is a year’s supply at one a day.

4 HIM & HERVitamin D3 50 µgCholecalciferol (D3) – 365 small tabletsView product →

Our higher strength provides 100 µg (4,000 IU) per tablet, which is the adult upper limit on its own. Do not combine it with other vitamin D supplements, or multivitamins containing vitamin D, without consulting a doctor.

4 HIM & HERVitamin D3 100 µgCholecalciferol (D3) – 365 small tabletsView product →

What is the best time of day to take vitamin D?

There isn’t one. Vitamin D can be taken at any time of day. Because it’s fat-soluble, taking it with a meal that contains some fat – breakfast with eggs or yoghurt, or your evening meal – is a sensible habit. The most useful thing is to take it at the same time each day so you don’t forget.

Is it better to take vitamin D every day or once a week?

For everyday use, take it daily. The NHS advice is given as a daily amount, and a steady daily dose is the simplest way to stay within the limit.

Weekly or monthly high-dose vitamin D is sometimes prescribed by a doctor, for example to treat a confirmed deficiency. Don’t create your own weekly dose by taking several days’ tablets at once – that’s a prescription-style dose and belongs under medical supervision.

How long does it take for vitamin D levels to go up?

Gradually. Vitamin D has to be converted in the liver and kidneys before the body can use it, so levels rise over weeks rather than days, and it can take a few months to reach a steady level. How far they rise depends on your starting level, your body weight and the dose. If you’ve been told your vitamin D is low, your GP will advise on retesting – see Vitamin D deficiency.