Clinical features of vitamin D deficiency

Vitamin D supports calcium handling, muscle function and bone health. Deficiency may cause few noticeable symptoms, or it may be associated with tiredness, muscle weakness, aches and low mood. In children, impaired bone development can be a concern; in adults, weakened bones may contribute to fractures. These features have many possible causes, including poor sleep, anaemia, thyroid disorders and other nutritional problems, so symptoms alone cannot confirm deficiency.

Discuss persistent fatigue, weakness, bone pain or repeated infections with a clinician, particularly if you have limited sun exposure, a condition affecting absorption, or take medicines that alter vitamin D processing. A blood test may be used alongside your history and examination. Use supplements only at the recommended dose, because excessive intake can be harmful. A clinician can advise on food sources, safe sunlight habits and whether treatment is needed.

Arrange a review for ongoing bone pain, muscle weakness, unexplained low mood or a fracture after minor impact. Seek urgent help for severe weakness, confusion, repeated vomiting, or symptoms after taking a large amount of a supplement. People with obesity, malabsorption or kidney and liver conditions may need individual advice rather than a standard supplement plan.

Ask whether your symptoms could have another cause, whether testing is appropriate, which dose and formulation suit you, and when your response should be reviewed. Ask how your other medicines and health conditions affect supplementation.