Every autumn, vitamin D supplements appear at the front of chemists and supermarkets. This article sums up what the NHS says about vitamin D in the UK winter, in plain English, so you can make an informed choice. It isn't medical advice: if you have a health condition, take other medicines, are pregnant or are buying for a child, check with a pharmacist or GP.
Why vitamin D comes up every winter
Our bodies make vitamin D when skin is exposed to sunlight. The NHS explains that in the UK, between October and early March we do not make enough vitamin D from sunlight. Vitamin D helps regulate the amount of calcium and phosphate in the body, which are needed to keep bones, teeth and muscles healthy.
It's also found in a small number of foods, such as oily fish (such as salmon, sardines, trout, herring or mackerel), red meat, egg yolks and fortified foods like some breakfast cereals and fat spreads. But it's hard for most people to get enough from food alone.
What the NHS recommends
According to the NHS vitamin D page:
- Adults and children from 1 year need 10 micrograms (mcg) of vitamin D a day.
- Everyone, including pregnant and breastfeeding women, should consider taking a daily supplement containing 10 micrograms of vitamin D during autumn and winter.
- Some groups are advised to consider taking a supplement all year round, for example people who are not often outdoors, such as those who are frail or housebound, people in care homes, people who usually wear clothes that cover most of their skin when outdoors, and people with dark skin.
- Babies and young children have specific advice depending on age and how they are fed. Children aged 1 to 4 should be given a daily supplement containing 10 micrograms all year round. Check the NHS page for babies under 1.
Micrograms and IU: reading the label
Supplement labels may use micrograms (mcg or µg) or international units (IU). The NHS notes that 10 micrograms is equal to 400 IU. So a tablet labelled "10µg (400 IU)" matches the general recommendation.
Many products in shops contain more than this, such as 25 micrograms (1,000 IU) or more. The NHS says that if you choose to take vitamin D supplements, 10 micrograms a day will be enough for most people. It also warns against taking too much over a long period, as this can cause too much calcium to build up in the body. The NHS page gives upper limits for different age groups; don't exceed them unless a doctor has advised you to.
Choosing a supplement: practical points
This isn't a recommendation of any brand. A few practical things to compare:
- Dose per tablet or drop: 10 micrograms (400 IU) matches the NHS general advice.
- Form: tablets, capsules, gummies, sprays and drops all exist. Choose one you'll actually take regularly.
- D3 or D2: most supplements use vitamin D3 (cholecalciferol). Vegans should check the source, as D3 is often derived from lanolin (sheep's wool), though plant-based versions exist.
- Other ingredients: some multivitamins already include vitamin D. Check you're not doubling up without realising.
- Price per day: a basic 10 microgram tablet is usually inexpensive. A higher price doesn't mean better results.
What vitamin D won't do
Supplement marketing sometimes implies vitamin D boosts energy, mood or immunity. Be cautious about these claims. The NHS advice focuses on bones, teeth and muscles. If you feel persistently tired, low or unwell in winter, speak to a GP rather than relying on supplements. Low mood that comes and goes with the seasons can be a recognised condition with effective treatments.
Who should talk to a professional first
Ask a pharmacist or GP before starting a supplement if you:
- Have kidney disease, a condition affecting calcium levels, or certain other medical conditions.
- Take medicines that might interact, or already take other supplements.
- Are buying for a baby or child and aren't sure of the right dose.
- Have been told you have low vitamin D and prescribed a higher dose; follow that advice instead.
Some families may be eligible for free vitamins through the NHS Healthy Start scheme; check the current eligibility on the NHS website.
Keeping it simple
If you decide to take vitamin D through the winter, the simplest approach is a single, basic 10 microgram supplement taken at the same time each day, for example with breakfast. A weekly pill organiser or keeping the pot next to your toothbrush makes it easier to remember. You don't need an expensive brand or a high-strength product unless a health professional has told you otherwise.
Other winter self-care habits
- Get outside in daylight when you can, even on cloudy days; it's good for general wellbeing even if the winter sun is too weak for vitamin D.
- Keep warm: the NHS suggests heating the rooms you use to at least 18°C if you can.
- Eat a varied diet including some of the vitamin D foods listed above.
Quick summary
- From October to early March, UK sunlight isn't strong enough for most people to make enough vitamin D.
- The NHS says everyone should consider 10 micrograms (400 IU) a day in autumn and winter, and some groups all year.
- More isn't better; stick to recommended amounts unless advised otherwise.
- Speak to a pharmacist or GP if you're unsure.
Our winter wellness under £15 guide includes small, low-cost self-care items, and always points back to this NHS advice for supplements.