How Much Vitamin D Should I Take? UK Doses and Upper Limits
How much vitamin D to take in the UK, from NHS and SACN guidance: 10µg a day in autumn and winter, who needs it all year, the 100µg adult upper limit and how to read a label.
By the GUUDIES Editorial Team · Updated 26 October 2026 · Claims checked against the GB Nutrition and Health Claims Register; sources below.
Disclosure: GUUDIES sells a daily gummy pouch that contains vitamin D. This guide follows NHS advice, which applies whichever brand you buy.
The short answer: the NHS says adults in the UK should consider taking 10 micrograms (10µg, or 400 IU) of vitamin D a day in autumn and winter, and some people should take it all year round. Adults should not take more than 100µg (4,000 IU) a day unless a doctor advises it.
How Much Vitamin D Should I Take a Day?
For most adults, 10µg a day is the figure to aim for. It is the UK reference intake set by the Scientific Advisory Committee on Nutrition (SACN) in 2016, and it is what the NHS advises (NHS; SACN). From about late March or early April to the end of September, most people can make enough vitamin D from sunlight on their skin. From October to early March, the UK sun is not strong enough, and food alone rarely provides 10µg a day. That is why the NHS suggests a daily supplement in autumn and winter.
| Who | NHS advice | Do not exceed |
|---|---|---|
| Adults | Consider 10µg a day in autumn and winter; all year if in a higher-risk group | 100µg (4,000 IU) a day |
| Children aged 1 to 4 | 10µg a day all year round | 50µg (2,000 IU) a day for ages 1 to 10 |
| Babies under 1 | 8.5 to 10µg a day if breastfed or having less than 500ml of formula a day | 25µg (1,000 IU) a day |
Adult products, including GUUDIES, are not for children. Use a children's supplement at the dose on its label.
Who Should Take Vitamin D All Year Round?
The NHS advises taking 10µg a day all year if you:
- are not often outdoors, for example if you are frail or housebound
- live in a care home
- usually wear clothes that cover most of your skin when outdoors
- have dark skin, for example if you have an African, African-Caribbean or South Asian background, as you may not make enough vitamin D from sunlight even in summer
If you are pregnant or breastfeeding, ask your midwife, GP or pharmacist which supplement is right for you; vitamin D is usually included in pregnancy supplements.
Can You Take Too Much Vitamin D?
Yes. Taking too many vitamin D supplements over a long period can cause too much calcium to build up in the body (hypercalcaemia), which can weaken bones and damage the kidneys and heart (NHS). That is why the NHS says adults should not take more than 100µg (4,000 IU) a day. If your doctor has prescribed a different amount, follow their advice. You cannot overdose on vitamin D from sunlight, but you should still protect your skin.
If you take more than one product, add them up. A multivitamin, a separate vitamin D tablet and fortified foods all count towards your total.
µg or IU? How to Read a Label
Labels use micrograms (µg, sometimes written mcg) or international units (IU). 1µg equals 40 IU.
| Micrograms | IU | % NRV | Context |
|---|---|---|---|
| 10µg | 400 IU | 200% | NHS daily advice |
| 20µg | 800 IU | 400% | Common in multivitamins |
| 25µg | 1,000 IU | 500% | Common single vitamin D tablet |
| 100µg | 4,000 IU | 2,000% | Adult upper limit |
The % NRV compares the amount with the 5µg nutrient reference value used on GB labels, which is lower than the 10µg NHS advice. So 200% NRV is the NHS amount, not double it.
Vitamin D3 or D2?
Supplements contain either vitamin D3 (cholecalciferol) or vitamin D2 (ergocalciferol). Both count towards the 10µg advice. D3 is the form most UK supplements use. Traditional D3 comes from lanolin (sheep's wool), so if you avoid animal products, look for D3 from lichen, or D2, and check the label.
When Is the Best Time to Take It?
Vitamin D is fat soluble, so many people take it with a meal. The time of day matters less than taking it every day. Gummies, tablets, capsules and sprays all work, as long as the product contains the amount on its label and you keep taking it.
Do You Need a Blood Test First?
Most people do not need a test to follow the 10µg advice. If you have symptoms such as bone pain or muscle weakness, or a condition that affects absorption, speak to your GP, who can decide whether a test is needed. Read more in our guide to vitamin D blood tests in the UK.
What Vitamin D Does
In Great Britain, the authorised health claims say that vitamin D contributes to the maintenance of normal bones, normal muscle function and normal teeth, to the normal function of the immune system, and to the normal absorption and use of calcium and phosphorus.
Where GUUDIES Fits
The Daily Greens+ gummy in each GUUDIES pouch contains 20µg (800 IU) of vitamin D3, 400% NRV. That is above the NHS 10µg advice and well within the 100µg adult upper limit. If you already take a separate vitamin D product, check that your combined total stays under 100µg. Find out more about the vitamin D3 in GUUDIES.
GUUDIES is one daily pouch of six pectin-based gummies for adults, with about 0.4g of sugar per gummy. Five of the six gummies are vegan; Marine Collagen contains fish.
Common Questions
How much vitamin D should I take a day in the UK?
The NHS advises adults to consider 10µg (400 IU) a day in autumn and winter, and all year if you are in a higher-risk group.
Is 25µg (1,000 IU) a day safe for adults?
Yes, it is below the 100µg adult upper limit. For babies under 1 it is the maximum, so use a baby product at the dose on its label.
Is 100µg (4,000 IU) a day too much?
100µg is the most the NHS says adults should take daily unless a doctor advises more. Do not go above it without medical advice.
Should I take vitamin D in summer?
Most people make enough from sunlight between late March and September. People in the all-year groups should keep taking it.
Can I get enough vitamin D from food?
Oily fish, eggs, red meat and fortified foods help, but few people get 10µg a day from food alone, which is why the NHS advice applies to everyone in winter.
Sources
- NHS, Vitamin D: nhs.uk
- Scientific Advisory Committee on Nutrition, Vitamin D and Health (2016): gov.uk
- GB Nutrition and Health Claims Register: gov.uk
Related Reading
Vitamin D Deficiency Symptoms · Vitamin D Blood Test UK · Vitamin D Gummies UK · Vitamin D UK Winter Guide · Vitamin D3 in GUUDIES
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