Vitamin D in Winter: How Much Do You Need in the UK?

The NHS says everyone in the UK should consider taking 10 micrograms (400 IU) of vitamin D a day in autumn and winter, because between October and early March we do not make enough from sunlight. Adults should not take more than 100 micrograms (4,000 IU) a day, and some people, such as those who are rarely outdoors, are advised to take 10 micrograms all year.

Key takeaways

• 10 micrograms a day in autumn and winter. That is the NHS amount for adults and children from age 1.
• 1 microgram is 40 IU. So 10 micrograms is 400 IU, 25 micrograms is 1,000 IU and 50 micrograms is 2,000 IU.
• Stay under the maximum. The NHS says 10 micrograms a day "will be enough for most people", and adults should not take more than 100 micrograms (4,000 IU) a day. Add up the vitamin D in every product you take.
• Some people should check first. With kidney problems, high calcium or sarcoidosis, if you are already prescribed vitamin D, or on digoxin or some water tablets, ask your GP or pharmacist. Our Saffron Gummies are not for use in pregnancy, while trying to get pregnant or breastfeeding, or by under-18s, anyone with phenylketonuria (PKU) or prone to allergies, or anyone allergic to any ingredient, and not with an autoimmune condition or immunosuppressants unless your doctor agrees. With bipolar disorder, a thyroid, liver, kidney or hormone-sensitive condition, high calcium, an operation coming up or another long-term condition, or on any regular medicine, including antidepressants, blood thinners, blood pressure medication and prescribed vitamin D, ask your GP or pharmacist first.

From us: Our Saffron Gummies contain 50 micrograms of vitamin D3 (2,000 IU, 1,000% NRV) per two gummies. That is five times the NHS 10 micrograms, twice an older UK guidance level of 25 micrograms for long-term supplement use, and half the NHS adult maximum of 100 micrograms. They also contain 300mg of saffron (from a 10:1 extract standardised to 3.5% crocin and safranal), 2,000mg of moringa, 2,000mg of maca, 200mg of rhodiola, 100mg of L-theanine, 100mg of magnesium, 50mg of spirulina extract and 5mg of black pepper extract. Vegan, £18.99 for 60 gummies (30 days), third-party lab tested.

Vitamin D at a glance

What is vitamin D, and why does winter matter?

Your skin makes vitamin D3 when direct sunlight falls on it outdoors. The NHS says most people should be able to make all they need this way from about late March or early April to the end of September. "But between October and early March we do not make enough vitamin D from sunlight." Few foods contain much: oily fish, red meat, egg yolks and fortified foods such as some fat spreads and breakfast cereals.

In the National Diet and Nutrition Survey for 2019 to 2023, 18% of adults aged 19 to 64 had blood levels below 25 nmol/L, the UK threshold for low vitamin D status. In January to March, the figure ranged from 21% to 38% across age and sex groups aged 11 and over.

What has been studied?

Unlike the botanicals in our gummies, vitamin D has authorised health claims in Great Britain. These are the seven general ones (the others are limited to children or older adults):

• Vitamin D contributes to normal absorption/utilisation of calcium and phosphorus.
• Vitamin D contributes to normal blood calcium levels.
• Vitamin D contributes to the maintenance of normal bones.
• Vitamin D contributes to the maintenance of normal muscle function.
• Vitamin D contributes to the maintenance of normal teeth.
• Vitamin D contributes to the normal function of the immune system.
• Vitamin D has a role in the process of cell division.

The Scientific Advisory Committee on Nutrition (SACN) set 10 micrograms as the amount most people need to keep blood levels at or above 25 nmol/L "when UVB sunshine exposure is minimal". UK advice for the general population does not go above that amount.

How much vitamin D do you need?

The NHS says adults and children from age 1 "need 10 micrograms (mcg) of vitamin D a day", including in pregnancy and while breastfeeding. All year, the Department of Health and Social Care recommends 10 micrograms a day for people over 4 who are not often outdoors, live in a care home, or usually cover most of their skin outdoors, and people with dark skin should consider it.

Our amounts are per two gummies, and our 50 micrograms is twice the 25 micrograms the UK's Expert Group on Vitamins and Minerals set in 2003 as a guidance level for long-term supplement use. If you want only the NHS 10 micrograms, a plain vitamin D supplement at that amount matches the advice.

Can you take too much vitamin D?

Yes, from supplements. The NHS says: "Taking too many vitamin D supplements over a long period of time can cause too much calcium to build up in the body (hypercalcaemia). This can weaken the bones and damage the kidneys and the heart." Sunlight does not cause this.

Add up every product:

• Take no more than two of our Saffron Gummies a day: four would be 100 micrograms, the NHS adult maximum.
• Our Super Greens Gummies also contain vitamin D3. The current label lists 25 micrograms (1,000 IU) per two gummies, but older bottles listed different amounts, up to 50 micrograms (2,000 IU), so check the label on yours. With Saffron Gummies, that is 75 micrograms (3,000 IU) a day on the current label, and up to 100 micrograms, the NHS adult maximum, with an older bottle.
• A separate vitamin D supplement or a multivitamin adds more. Count it in, and do not go over 100 micrograms (4,000 IU) a day in total.
• Our Sea Moss and Ashwagandha Gummies contain none, so the Daily Three gives 50 micrograms.

Keep the bottle out of reach of children. The NHS says to contact 111 if a child aged 1 to 10 has had more than 2,000 IU in a day, which is more than two of our gummies.

Who should avoid it or check first

Do not take our Saffron Gummies if you:

• are pregnant, trying to get pregnant, breastfeeding or under 18
• are allergic to any ingredient, including moringa, rhodiola and spirulina
• have phenylketonuria (PKU) or are prone to allergies (for the spirulina)
• have an autoimmune condition or take immunosuppressants, unless your doctor agrees (for the spirulina)

Ask your GP or pharmacist first if you:

• have bipolar disorder, or take antidepressants or other mood medication (for the saffron and rhodiola)
• take blood thinners such as warfarin, aspirin or clopidogrel, blood pressure medication or diabetes medicine
• take digoxin, water tablets or epilepsy medicine such as phenytoin (for the vitamin D3 and rhodiola)
• have a thyroid condition or take thyroid medicine (for the moringa)
• have a liver condition (for the rhodiola)
• have, or have had, a hormone-sensitive condition, such as breast or womb cancer (for the maca)
• are having hormone blood tests: tell your doctor you take maca
• have high calcium in your blood or urine, high vitamin D levels, kidney problems or kidney stones, or sarcoidosis (for the vitamin D3)
• are prescribed vitamin D: the NHS says not to add other vitamin D or calcium supplements without your doctor's advice
• have an operation coming up or another long-term condition, or take any other regular medicine

The NHS 10 micrograms still applies in pregnancy and breastfeeding, so ask your midwife, GP or pharmacist which supplement to use.

If a new symptom appears, stop and speak to your GP or a pharmacist. More in Saffron Side Effects and Safety: What to Check First. Food supplements are not a substitute for a varied diet and a healthy lifestyle.

Vitamin D and medicines

The NHS asks you to tell your doctor before taking vitamin D (colecalciferol) if you take:

• digoxin (a heart medicine) or water tablets such as bendroflumethiazide or indapamide, as blood calcium may get too high
• epilepsy medicines such as phenytoin, carbamazepine, phenobarbital or primidone, or steroids such as prednisolone, which may reduce vitamin D's effect
• cholestyramine or paraffin laxatives, which may reduce absorption
• ketoconazole, clotrimazole or actinomycin, which may affect how it is broken down

List prices, before any discount code, correct on 1 November 2026.

Frequently asked questions

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

The NHS says everyone should consider a daily 10 microgram (400 IU) vitamin D supplement in autumn and winter, because between October and early March we do not make enough from sunlight. Adults should not take more than 100 micrograms (4,000 IU) a day. If your doctor has recommended a different amount, follow their advice.

Is 2,000 IU of vitamin D a day too much?

For adults, 2,000 IU (50 micrograms) a day is within the NHS maximum of 4,000 IU, but it is five times the 400 IU the NHS says is enough for most people, and twice a 1,000 IU guidance level for long-term supplement use set by UK experts in 2003. For children aged 1 to 10, 2,000 IU is the NHS daily maximum. Add up the vitamin D in every product you take, and do not go over 4,000 IU a day in total. If your doctor has prescribed vitamin D, follow their advice and do not add another supplement without asking. Ask a GP or pharmacist first if you have kidney problems, high calcium or sarcoidosis, or take digoxin or water tablets.

How many IU is 10 micrograms of vitamin D?

10 micrograms is 400 IU, because 1 microgram of vitamin D is 40 IU. So 25 micrograms is 1,000 IU, 50 micrograms is 2,000 IU and 100 micrograms, the NHS daily maximum for adults, is 4,000 IU.

Is vitamin D3 better than D2, and is it vegan?

A 2024 review by the UK's Scientific Advisory Committee on Nutrition found D3 (colecalciferol), the form made in skin, slightly better than D2 (ergocalciferol) at raising blood vitamin D levels, but said the difference may not be reliable. D3 is not always vegan: the Vegan Society says many supplements use D3 from lanolin, from sheep's wool, while vegan D3 can come from lichen, and D2 is not derived from animals.

What are the benefits of vitamin D?

Vitamin D has seven general authorised health claims in Great Britain, including: vitamin D contributes to the maintenance of normal bones; vitamin D contributes to the maintenance of normal muscle function; and vitamin D contributes to the normal function of the immune system.

Can I take vitamin D with my medicines?

Ask your GP or pharmacist first. The NHS lists digoxin, some water tablets, epilepsy medicines, steroids, cholestyramine, paraffin laxatives, some antifungals and actinomycin. If you are prescribed vitamin D, do not add other vitamin D or calcium supplements without your doctor's advice. Our Saffron Gummies are not for use in pregnancy, while trying to get pregnant or breastfeeding, or by under-18s, anyone with phenylketonuria (PKU) or prone to allergies, or anyone allergic to any ingredient, and not with an autoimmune condition or immunosuppressants unless your doctor agrees. With bipolar disorder, a thyroid, liver, kidney or hormone-sensitive condition, high calcium, an operation coming up or another long-term condition, or on any regular medicine, including antidepressants, blood thinners, blood pressure medication and prescribed vitamin D, ask your GP or pharmacist first.

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References

1. NHS. "Vitamin D." Page last reviewed 03 August 2020, checked 1 November 2026. nhs.uk.
2. NHS. "Who can and cannot take colecalciferol", "How and when to take colecalciferol" and "Taking colecalciferol with other medicines and herbal supplements." Pages last reviewed 10 January 2023. nhs.uk.
3. Scientific Advisory Committee on Nutrition. "Fortifying foods and drinks with vitamin D: summary." Published 23 May 2024. gov.uk.
4. Office for Health Improvement and Disparities and Food Standards Agency. "National Diet and Nutrition Survey 2019 to 2023: report." 11 June 2025. gov.uk.
5. The Vegan Society. "Vitamin D." vegansociety.com.
6. "Commission Regulation (EU) No 432/2012 of 16 May 2012 establishing a list of permitted health claims made on foods, other than those referring to the reduction of disease risk and to children's development and health", Annex, as retained in Great Britain. legislation.gov.uk.
7. Regulation (EU) No 1169/2011 on the provision of food information to consumers, Annex XIII, as retained in Great Britain. legislation.gov.uk.
8. EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA). "Scientific opinion on the tolerable upper intake level for vitamin D, including the derivation of a conversion factor for calcidiol monohydrate." EFSA J, 2023. doi:10.2903/j.efsa.2023.8145
9. Verkaik-Kloosterman J et al. "Vitamins and minerals: issues associated with too low and too high population intakes." Food Nutr Res, 2012. doi:10.3402/fnr.v56i0.5728

Food supplements are not intended to treat, cure or prevent any disease. If you are pregnant, breastfeeding, taking medication, or have a medical condition, consult a healthcare professional before use.