Quick answer: Between October and early March, the NHS says everyone should consider taking a daily vitamin D supplement of 10 micrograms (400 IU), because UK sunlight is too weak for your skin to make enough. If you are frail or housebound, live in a care home, usually cover your skin outdoors, or have dark skin, consider taking it all year. Vitamin D helps keep bones and muscles healthy but is not a treatment for arthritis itself. Do not take more than 100 micrograms a day unless a doctor advises it.
October is when UK sunlight becomes too weak for your skin to make the vitamin D your body needs, and that lasts until about early March. If arthritis already keeps you indoors more, or you are older or living with frailty, winter can leave you short. This guide explains what the NHS advises, who should take vitamin D all year, how to take it safely alongside arthritis medicines, and what vitamin D can and cannot do for your joints.
What the NHS advises this autumn and winter
- Between October and early March, the NHS says everyone should consider taking a daily supplement containing 10 micrograms (400 IU) of vitamin D
- From about late March or early April to the end of September, most people can make enough vitamin D from sunlight on their skin, so you may choose not to take a supplement in those months
- Vitamin D supplements are sold in most pharmacies and supermarkets. A pharmacist can help you choose one and check it fits with your other medicines
Who should consider vitamin D all year round
The NHS advises a daily 10 microgram supplement throughout the year if you:
- are not often outdoors, for example because you are frail or housebound
- live in a care home or other institution
- 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
If painful joints mean you rarely get outside, the first point may apply to you even if you would not call yourself frail.
What vitamin D can and cannot do for arthritis
Vitamin D helps your body control calcium and phosphate, which keep bones, teeth and muscles healthy. A real lack of vitamin D in adults can cause bone pain and muscle weakness (a condition called osteomalacia), which is worth getting checked if your aches feel different from your usual arthritis.
The NHS advice on vitamin D is about bone and muscle health. It is not a treatment for arthritis itself, so keep up your usual treatment, exercise and pain relief plan. NICE guidance for osteoarthritis puts exercise and weight management at the centre of care. Our supplements guide and supplements hub explain the evidence on other products.
Bones, steroids and falls
- Long-term use of high-dose steroid tablets, and conditions such as rheumatoid arthritis, can raise the risk of osteoporosis (thinning bones). If you take steroid tablets long term, ask your GP or rheumatology team whether you need bone protection. Our bone protection on steroids guide explains the questions to ask. Never stop steroid tablets suddenly or change the dose without advice
- Bones and muscles both matter for falls. Strength and balance exercise helps most; see the exercise hub, our falls prevention guide and vitamin D and falls guide
- If you have been told you have osteoporosis, our osteoporosis and arthritis guide covers bones and joints together
Taking vitamin D safely
- For most people, 10 micrograms a day is enough. More is not better
- The NHS says adults should not take more than 100 micrograms (4,000 IU) a day, as too much over a long time can raise calcium levels and harm bones, kidneys and the heart
- Some medical conditions mean you may not be able to safely take as much. If in doubt, ask your GP or pharmacist first
- If your doctor has prescribed a different dose, for example to treat a low level, follow their advice
- Check labels so you do not double up. Multivitamins and some calcium tablets already contain vitamin D
- Tell your pharmacist about any supplements you take alongside arthritis medicines, and do not stop or change prescribed medicines yourself
Food sources of vitamin D
Only a few foods contain vitamin D, which is why food alone is unlikely to be enough in winter. Sources include oily fish such as salmon, sardines, trout, herring and mackerel, red meat, egg yolks, and fortified foods such as some fat spreads and breakfast cereals. Liver also contains it, but avoid liver if you are pregnant. In the UK, cows' milk is generally not a good source. For eating well with arthritis, see the diet hub and our protein and frailty guide.
If you care for someone
If the person you care for is housebound or lives in a care home, the NHS advice is to consider vitamin D all year, not just in winter. Ask their GP or pharmacist if you are unsure, especially if they take several medicines. A carer's assessment can help if shopping and medicines are becoming hard to manage.
When to get help
- See your GP if you have bone pain, new muscle weakness, or aches that feel different from your usual arthritis
- See your GP if you have fallen, or you take steroid tablets long term and have never discussed bone health
- Call 999 after a fall if you cannot get up or put weight on a leg, or you have severe hip or groin pain
- For urgent advice, contact NHS 111 (NHS 24 on 111 in Scotland)
Frequently asked questions
Does vitamin D help arthritis pain?
The NHS recommends vitamin D for healthy bones and muscles, not as a treatment for arthritis. If you have pain that feels new or different, see your GP rather than taking more vitamin D.
Do I need a blood test before taking vitamin D?
The NHS advice to consider 10 micrograms a day in autumn and winter applies to everyone, so it does not depend on a blood test. Your GP may check your level if you have symptoms such as bone pain or you are at higher risk.
Can I take vitamin D with methotrexate or other arthritis medicines?
Ask your pharmacist or rheumatology team, who can check your full list of medicines. Keep taking your prescribed medicines as directed while you check.
Sources and further reading
- NHS: Vitamin D
- NHS: Preventing osteoporosis
- NHS: Causes of osteoporosis
- NHS: Falls
- GOV.UK: SACN vitamin D and health report
- NICE NG226: Osteoarthritis in over 16s
Educational information for people in the United Kingdom — not a diagnosis or personal medical advice. Charity no. 1218461. Pending clinical review. Everyone's situation is different, so always follow the advice of your own GP, pharmacist or rheumatology team. If you feel very unwell, call 999 or go to A&E. For urgent advice, contact NHS 111.
Continue with related help
- Vitamin D and falls — bones, muscles and staying steady
- Bone protection on steroids — questions to ask
- Supplements for arthritis — what the evidence says
- Diet hub — eating well with arthritis
- Exercise hub — strength and balance
- Falls prevention — safer moving at home
- Cold home and arthritis — keep warm and keep moving
- Newly diagnosed — first steps