The 30-second version
- Very low vitamin D can cause bone pain, muscle weakness and bones that break easily.
- The NHS does not routinely test people without symptoms; it simply advises a daily supplement.
- A multivitamin may not contain the full 10 micrograms the NHS recommends – check the label.
- High-dose treatment is for confirmed deficiency only, and must be prescribed.
On this page
Most of us in the UK should consider a daily vitamin D supplement over winter (NHS advice; see also our guide, The Sunshine Vitamin). But what if you think your levels are already low? Here is what to look out for, and what the NHS can do.
Signs your vitamin D may be low
Very low vitamin D over time can cause rickets in children and osteomalacia (soft bones) in adults. Signs include (sources: NHS, NICE adults, NICE children):
| Area | Adults | Children |
|---|---|---|
| Bones | Pain in the back, shoulders, ribs, pelvis or legs | Bowed legs, swollen or painful wrists, bone pain |
| Muscles | Muscle weakness that makes moving about harder; tingling, cramps or twitching | Weak muscles; tingling, cramps or twitching |
| Movement | Changes in the way you walk | Changes in the way they walk |
| Breaks | Bones break more easily | Bones break more easily |
| Growth and teeth | – | Smaller than average; teeth come through late |
These symptoms can have other causes, so speak to a GP rather than guessing.
How do I get a vitamin D test on the NHS?
The NHS does not routinely test people without symptoms, even those at higher risk of low vitamin D. If that is you, the advice is simply to take the daily supplement.
Under NICE guidance, your GP may offer a blood test if you have:
- symptoms like those above that will not go away
- osteoporosis, or a broken bone from a minor fall
- plans to start certain bone-strengthening medicines
Book a GP appointment and describe your symptoms clearly: what you feel, where, and for how long. If a test is needed, it is a simple blood sample.
Key insight: Testing is for people with symptoms or bone problems. For everyone else, the NHS advice is the same: a daily 10 microgram supplement.
Multivitamin, everyday vitamin D or treatment dose?
An everyday vitamin D supplement contains the 10 micrograms the NHS recommends. A multivitamin contains a little of many vitamins, and its vitamin D may be less than 10 micrograms, so check the label. If you take both, add them together and stay under the NHS daily upper limit of 100 micrograms for adults.
A therapeutic (treatment) dose is different. If a blood test shows very low vitamin D, your GP may prescribe a short, high-dose course to bring your levels back up, following NICE guidance and local NHS prescribing guidance (for example, Sussex). Treatment doses for children are different and are set out in NICE guidance for children. These doses are far above the everyday limit, so only take them if prescribed.
| Feature | Everyday vitamin D | Multivitamin | Therapeutic vitamin D |
|---|---|---|---|
| What it is for | Keeping your levels topped up | A small top-up of lots of vitamins and minerals | Treating a deficiency confirmed by a blood test |
| Dose | 10 micrograms (400 IU) a day | Varies – check the label | Much higher, for example around 300,000 units in total over 6 to 12 weeks |
| Source | NHS | Product label | NICE (adults); NHS Sussex prescribing guidance |
| Who decides | You, following NHS advice | You | Your GP or specialist |
| How long | October to early March, or all year | Ongoing | A short course |
What happens after treatment?
After a treatment course, your GP may check the calcium level in your blood. You will then usually be advised to carry on with a lower daily dose to stop your levels dropping again. You may be asked to buy this yourself from a pharmacy or supermarket, where vitamin D is low-cost.
Do not stop or change a prescribed course without talking to your GP or pharmacist.
Support at appointments
- If English is not your first language, you have a right to interpreting support at NHS appointments. Ask for an interpreter when you book.
- Public Health Scotland's leaflet Vitamin D and you is available in Easy Read and audio versions.
The bottom line
If you have ongoing bone pain or muscle weakness, see your GP. Do not self-treat with high doses. For most people, a simple 10 microgram daily supplement (NHS advice) is all that is needed.
Read next
This post is general information, not personal medical advice. Speak to your GP or pharmacist about your own health.
References
Arthritis UK (no date) Osteoporosis: symptoms, causes and treatment. Available at: https://www.arthritis-uk.org/information-and-support/understanding-arthritis/conditions/osteoporosis/ (Accessed: 4 October 2026).
Manchester University NHS Foundation Trust (no date) Serum vitamin D test requesting. Available at: https://mft.nhs.uk/the-trust/other-departments/laboratory-medicine/information-for-gps/laboratory-medicines-newsletter-for-gps/serum-vitamin-d-test-requesting/ (Accessed: 4 October 2026).
NHS (no date) Rickets and osteomalacia. Available at: https://www.nhs.uk/conditions/rickets-and-osteomalacia/ (Accessed: 4 October 2026).
NHS (no date) Vitamin D. Available at: https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/ (Accessed: 4 October 2026).
NHS England (no date) Improvement framework: community language translation and interpreting services. Available at: https://www.england.nhs.uk/long-read/improvement-framework-community-language-translation-and-interpreting-services/ (Accessed: 4 October 2026).
National Institute for Health and Care Excellence (2022) Vitamin D deficiency in children. Clinical Knowledge Summaries. Available at: https://cks.nice.org.uk/topics/vitamin-d-deficiency-in-children/ (Accessed: 4 October 2026).
National Institute for Health and Care Excellence (2026) Vitamin D deficiency in adults. Clinical Knowledge Summaries. Available at: https://cks.nice.org.uk/topics/vitamin-d-deficiency-in-adults/ (Accessed: 4 October 2026).
Public Health Scotland (2026) Vitamin D and you. Available at: https://publichealthscotland.scot/publications/vitamin-d-and-you (Accessed: 4 October 2026).
Sussex Health and Care Partnership (2024) Vitamin D management in adults. Available at: https://clinical.surreysussex.icb.nhs.uk/clinical_documents/vitamin-d-management-in-adults/ (Accessed: 4 October 2026).
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