Why is my vitamin D low?

Vitamin D is made in skin exposed to sunlight and also comes from food and supplements. Levels may be lower when someone spends little time outdoors, covers most skin, has darker skin, or eats few vitamin-D-containing foods. Obesity can affect how vitamin D is distributed in the body. Conditions affecting digestion or absorption, kidney or liver function, and some medicines can also contribute. A low result does not prove which factor is responsible, and it does not by itself explain symptoms. Fatigue, generalised weakness, joint pain, low mood, or frequent infections can have many causes. Your clinician may review these possibilities and consider bone health.

Bring the laboratory report and a list of medicines, supplements, and relevant health conditions to your appointment. Ask whether the result should be repeated or whether another test is useful. Treatment may involve a clinician-selected supplement, dietary changes, or a plan for safe sunlight exposure. Do not combine several vitamin products without checking their ingredients. Tell your clinician about kidney stones, kidney disease, digestive symptoms, pregnancy, or medicines that affect calcium or vitamin D. If a low level was found during an evaluation for tiredness or pain, keep investigating those symptoms if they do not improve.

Book medical advice for persistent bone pain, muscle weakness, repeated falls, or concern about a stress fracture. Seek urgent assessment for severe injury-related pain, inability to walk, new confusion, persistent vomiting, or severe weakness. These warning signs need prompt evaluation and should not be assumed to result from vitamin D alone.

Ask what might account for your result, whether your medicines or digestion could play a part, what treatment is suitable, and when the level or symptoms should be reviewed.