What should you know about NICE vitamin D deficiency guidance?

Vitamin D helps the body use calcium and supports bone and muscle function. Deficiency may cause no clear symptoms, but some people notice fatigue, generalised weakness, muscle or joint pain, or changes in bone strength. These symptoms have many possible causes, so they do not prove that vitamin D is low. A clinician considers diet, sunlight exposure, medicines, health conditions and risk of bone injury when deciding whether testing is appropriate.

Ask a clinician whether your symptoms or risk factors call for a blood test. Discuss a suitable supplement, dose and duration rather than taking several products together. Follow label or prescription instructions and mention kidney problems, pregnancy, digestive conditions and all other supplements. Food sources, safe outdoor activity and advice about bone health may form part of the plan. If treatment is started, ask when progress or repeat testing should be reviewed.

Arrange prompt assessment for new severe bone pain, difficulty walking, repeated falls or a suspected stress fracture. Seek urgent help after a significant injury, or for severe weakness, confusion, vomiting or other symptoms that make you feel acutely unwell. Do not take extra vitamin D to treat worsening symptoms without professional advice.

Ask whether testing is needed, what may have caused the deficiency, which supplement is appropriate, and how calcium, kidney health and bone strength will be considered. Mention fatigue, low mood, frequent infections or pain, because these symptoms may need separate assessment.