Reviewed by a GPhC-registered pharmacist at Priory Pharmacy · 3 min read
Quick answer: The NHS advises most adults and children over 4 in York to consider taking a daily vitamin D supplement of 10 micrograms (400 IU) between October and early March, when there is not enough sunlight for your body to make enough vitamin D. Some people are advised to take it all year round, including those who rarely go outdoors, live in a care home, usually cover most of their skin when outside, or have dark skin, such as people of African, African-Caribbean or South Asian origin. Children aged 1 to 4 should have 10 micrograms every day all year, and breastfed babies need 8.5 to 10 micrograms a day from birth. It is hard to get enough vitamin D from food alone, but adults should not take more than 100 micrograms (4,000 IU) a day unless a doctor advises it, as too much can be harmful. Speak to your GP if you have symptoms such as bone pain or muscle weakness, as you may need a blood test rather than a standard supplement. In York, ask your local pharmacist which vitamin D product is right for you and whether it is safe with any medicines you take.
Key takeaways
- Standard dose: 10 micrograms (400 IU) daily for everyone aged 1 and over, including pregnant and breastfeeding women.
- Timing: autumn and winter for most people; all year for at-risk groups, children aged 1 to 4 and babies.
- Ceiling: 100 micrograms (4,000 IU) daily for adults and children 11 to 17; lower limits for younger children.
- Testing: the 25-hydroxy vitamin D blood test measures your stores; the NHS does not test routinely without a clinical reason.
- Form: D3 is the usual choice in the UK, but consistency matters more than which type you buy.
Why Vitamin D Matters More in York Than You Might Think
Almost everyone in York has heard that a walk outside tops up their vitamin D. It is true for part of the year, and misleading for the rest.
Vitamin D regulates the amount of calcium and phosphate in your body. Those minerals keep bones, teeth and muscles healthy. Too little vitamin D leads to bone deformities such as rickets in children, and to bone pain from osteomalacia in adults.
The northern England problem: York sits at roughly 54° north. UVB light is only strong enough for your skin to make vitamin D from late March to the end of September. From October to early March, you make little or none, however many clear days we get.
That is the vitamin D winter window – and it is longer and deeper here than the national headlines suggest.
Even in summer, several things blunt production: covering up, sunscreen, working indoors, cloud, pollution, and darker skin (more melanin means longer exposure is needed for the same amount).
What vitamin D actually does:
- Helps your gut absorb calcium from food
- Keeps phosphate levels in the normal range
- Supports normal muscle function and reduces the risk of falls in older adults
- Contributes to normal immune system function
- Is needed for normal growth and bone development in children
How Much Vitamin D Should I Take?
Short answer: 10 micrograms a day. That is 400 IU. One microgram of vitamin D equals 40 IU, so 10 micrograms and 400 IU are the same dose written two ways.
The NHS vitamin D guidance sets the reference nutrient intake at 10 micrograms daily for children from 1 year and adults – including pregnant and breastfeeding women, and anyone at risk of deficiency. Babies up to 1 year need 8.5 to 10 micrograms daily.
NHS daily vitamin D dosage at a glance
| Who | Daily vitamin D dosage | When |
|---|---|---|
| Breastfed babies, or formula-fed babies having less than 500ml a day | 8.5 to 10 micrograms (340 to 400 IU) | All year |
| Children aged 1 to 4 | 10 micrograms (400 IU) | All year |
| Children 1+ and adults, including pregnant and breastfeeding women | 10 micrograms (400 IU) | Autumn and winter at minimum |
| Adults and children over 4 in an at-risk group | 10 micrograms (400 IU) | All year |
| Upper limit: adults, 11 to 17 year olds, pregnant and breastfeeding women | Do not exceed 100 micrograms (4,000 IU) | – |
| Upper limit: children aged 1 to 10 | Do not exceed 50 micrograms (2,000 IU) | – |
| Upper limit: infants under 12 months | Do not exceed 25 micrograms (1,000 IU) | – |
These figures are total daily intake from supplements. Your diet contributes a little; 10 micrograms is the top-up, not a target to beat.
If you have been advised a higher dose for a diagnosed deficiency, follow your prescriber rather than the general table. Higher doses are a treatment, not a lifestyle upgrade.
Who needs a vitamin D supplement all year?
Take 10 micrograms daily right through the year if you:
- Are frail or housebound, so you rarely get outdoors
- Live in a care home or similar setting
- Usually wear clothes that cover most of your skin outdoors
- Have darker skin – for example African, African-Caribbean or south Asian heritage
- Are a child aged 1 to 4, or a baby in the infant groups above
Pregnancy and breastfeeding do not change the 10 microgram dose, but they do make it non-negotiable.
Signs of Vitamin D Deficiency You Should Not Ignore
Here is the part most people get wrong: vitamin D deficiency is often silent. Many people with low levels feel nothing at all, and the problem is found on a blood test taken for another reason.
When symptoms do appear, the signs of vitamin D deficiency are vague and easy to blame on a busy life:
- Bone pain or tenderness, most often in the legs, pelvis or ribs
- Muscle aches and weakness – struggling on stairs, or pushing up out of a chair
- Muscle cramps, twitching or aching that comes on without obvious cause
- Tiredness and low mood, which are common but not specific to vitamin D
- Unsteadiness or more frequent falls, particularly in older adults
- In children: delayed growth, bow legs, a waddling walk, or late dental development
None of these confirms deficiency on its own. Joint pain, thyroid problems, anaemia, low calcium and simple ageing can all look similar. That is why we would rather you describe your symptoms to us or your GP than match yourself against a list online.
Seek urgent help if you have severe muscle spasms, seizures, or marked weakness – these can signal very low calcium and need same-day assessment.
How Vitamin D Deficiency Is Tested
The test is a serum 25-hydroxy vitamin D blood test, usually written 25(OH)D. It measures your vitamin D stores. The active form, 1,25-dihydroxyvitamin D, is not the routine test for deficiency.
What the numbers mean (UK thresholds):
- Below 25 nmol/L: deficient
- 25 to 50 nmol/L: may be inadequate, depending on your circumstances
- Above 50 nmol/L: generally sufficient for bone health
Your GP will interpret the result alongside your symptoms, medicines and other blood tests.
NHS testing versus private testing
The NHS does not recommend routine vitamin D testing for people without symptoms, even when risk factors are present. A GP may request it if you have symptoms that fit, suspected bone disease, or a result is needed before certain treatments.
Private testing is widely available and uses the same 25(OH)D test. Two practical cautions:
- Check what is included – whether a clinician interprets the result, and whether follow-up is offered.
- A number is not a diagnosis. A result on its own, without symptoms and history, can lead to over-treatment as easily as under-treatment.
If you have a private result you do not understand, bring it in. We will talk it through and point you back to your GP if treatment is needed.
Vitamin D2 vs D3: Does the Type Matter?
Both raise your vitamin D level. D3 is usually the better buy, but only if you actually take it.
- Vitamin D2 (ergocalciferol): produced from yeast or plant sterols; the form used in some prescriptions and many fortified foods.
- Vitamin D3 (cholecalciferol): the form your skin makes; in most UK supplements it is derived from lanolin (sheep’s wool), or from lichen in vegan products.
Research generally shows D3 raises blood 25(OH)D slightly more than D2 at the same dose. The NHS does not specify a preferred form, and for a 10 microgram daily supplement the difference is small. What matters more is taking it every day, at a dose you can sustain.
If you follow a vegan diet, look for lichen-derived D3 or a D2 product. If you prefer to avoid animal-derived gelatin capsules, choose tablets or a liquid instead.
Vitamin D Foods: What Actually Moves the Needle
Very few foods contain meaningful vitamin D, and the ones that do are not the ones most of us eat daily.
Sources of vitamin D in the UK diet:
- Oily fish – salmon, sardines, mackerel, trout, herring
- Red meat
- Egg yolks
- Fortified foods – some fat spreads, breakfast cereals and plant milks
- Liver (avoid in pregnancy)
Two details matter here:
- UK cows’ milk is not fortified, unlike in some other countries, so milk is not a useful vitamin D source here.
- Fortification varies by product. Check the label rather than assuming.
Even a good diet of oily fish, eggs and fortified spread rarely reaches 10 micrograms a day reliably, which is why the national advice is a supplement rather than a food-first target. Food supports your intake; it does not replace the tablet in winter.
Choosing a Vitamin D Supplement: What to Check
The vitamin D supplement market is crowded, and the loudest labels are not the most useful. Ignore the marketing and read the panel.
Check these five things before you buy:
- Look for the dose per daily dose, not per tablet – two tablets may be needed for the stated amount
- Expect 10 micrograms (400 IU) for routine use; question anything offering many multiples of that
- Confirm the form (D3 is standard; D2 and lichen D3 suit vegan diets)
- Check the base – gummies and chewables often contain sugar or gelatin; drops suit infants and anyone who cannot swallow tablets
- Watch combination products: a multivitamin plus a separate vitamin D can quietly double your intake
A note on cod liver oil: it supplies vitamin D but also vitamin A. Do not use high-dose cod liver oil in pregnancy without checking with us first.
A note on sprays and sublingual drops: they are convenient and no better absorbed than a standard tablet for most people. Choose on adherence, not on claims.
In the UK, vitamin D supplements are classed as food supplements, so the label is your only guarantee of content. A pharmacy product with a clear dose per serving is the safer buy.
Our Take: More Is Not Better
The single most common mistake we see is assuming that if 10 micrograms is good, 100 must be better. It is not a strength contest.
Vitamin D is fat-soluble and accumulates. Doses well above 100 micrograms a day, taken over months, risk harm without added benefit for most people. A 4,000 IU capsule is the adult upper limit – a ceiling, not a target. For routine prevention in a healthy adult in York, 10 micrograms from October to March is the evidence-based dose, and no amount of marketing changes that.
What Happens If You Take Too Much Vitamin D?
Taking too many vitamin D supplements over a long period causes too much calcium to build up in the blood – hypercalcaemia. That can weaken the bones and damage the kidneys and the heart.
The NHS upper limits:
- Adults, 11 to 17 year olds, pregnant and breastfeeding women, and older people: no more than 100 micrograms (4,000 IU) a day
- Children aged 1 to 10: no more than 50 micrograms (2,000 IU) a day
- Infants under 12 months: no more than 25 micrograms (1,000 IU) a day
You cannot overdose on vitamin D from sunlight. The body limits how much it makes. Supplement doses are the only realistic route to excess.
Some medical conditions mean a lower ceiling applies – for example kidney disease, a history of high calcium, or some inflammatory conditions. Tell your pharmacist or GP before starting a high-dose supplement.
Signs of high calcium to act on: nausea, vomiting, excessive thirst, passing large volumes of urine, constipation, confusion or unexplained fatigue. Stop the supplement and get advice the same day.
Free Vitamin D Through Healthy Start
Not everyone should be paying for supplements. Women and children who qualify for the Healthy Start scheme can get free supplements containing vitamin D, along with healthy start food payments.
The scheme covers eligible pregnant women and children under 4, and the vitamins supply the standard 10 micrograms of vitamin D, plus vitamins A and C. Ask us if you are unsure whether you qualify, or whether the children’s drops are the right format for your child.
Getting the Right Dose in York
General advice gets most people to the right place. A short conversation gets everyone else there.
What we can do at Priory Pharmacy:
- Check your current supplements for double-dosing and overlaps
- Review vitamin D alongside your other medicines, including calcium and cod liver oil products
- Advise on the right format for infants, children, older adults and anyone who struggles with tablets
- Talk through a private or NHS test result and explain what it means
- Point you to your GP when testing or treatment is the correct next step
Book a vitamin D and supplements consultation at Priory Pharmacy in York, or call us on 01904 404101 and we will talk it through before you buy anything.
Useful sources
- NHS: Vitamin D – doses, at-risk groups, food sources and upper limits
- NICE PH56: Vitamin D – supplement use in specific population groups
- Scientific Advisory Committee on Nutrition: Vitamin D and health report
- NHS: Rickets and osteomalacia
- NHS Healthy Start – free vitamins for eligible families
Frequently Asked Questions
From about late March or early April to the end of September, most people can make all the vitamin D they need from sunlight on their skin. From October to early March, the sunlight in the UK is not strong enough for your body to make enough vitamin D, so the NHS advises considering a daily supplement during this time.
For most adults and children over 1, yes. A daily dose of 10 micrograms matches NHS advice and the Scientific Advisory Committee on Nutrition’s recommended intake for everyone aged 4 and over. Higher doses are usually only needed if you have been diagnosed with a vitamin D deficiency or a clinician has advised it.
Multiply the number of micrograms by 40. This means 10 micrograms is 400 IU and 25 micrograms is 1,000 IU. If a product label only shows IU, divide the figure by 40 to compare it with the NHS advice, which is given in micrograms.
Not usually. For everyday prevention, the NHS advises taking a supplement without needing a test first. It is worth speaking to your GP about a blood test if you have bone pain, muscle weakness, a fracture from a minor fall, a condition that affects how your body absorbs vitamin D, or you have been taking a high dose for a long time.
Vitamin D helps your immune system work normally, but there is not enough evidence to recommend taking it to prevent or treat colds or COVID-19. The main reason to take a supplement is to keep your bones, teeth and muscles healthy, especially during the autumn and winter months.
Yes. Babies under 1 need 8.5 to 10 micrograms of vitamin D a day if they are breastfed or have less than 500ml of formula a day, and children aged 1 to 4 need 10 micrograms every day all year. Children also have lower upper limits, with no more than 25 micrograms a day for babies under 1 and no more than 50 micrograms a day for children aged 1 to 10.
Usually yes, but it is important to check how much vitamin D you are getting in total. Multivitamins, calcium and vitamin D tablets, cod liver oil and fortified drinks can all contain vitamin D. Bring your supplements into the pharmacy and our pharmacist can help you check the total amount and make sure they are safe with any medicines you take.
If you have dark skin, such as if you are of African, African-Caribbean or South Asian origin, the NHS advises considering a 10 microgram vitamin D supplement every day all year, because your skin may not make enough vitamin D from sunlight. The same advice applies if you usually cover most of your skin when outdoors or spend most of your time indoors.