Background Public Health England advises 400 IU/day vitamin D supplementation for children over 1 year. Commercially available children’s multivitamin and vitamin D supplements were surveyed to determine the vitamin D content.

Methods Multivitamins and vitamin D supplements marketed at children <12 years and sold by nine UK supermarkets and health supplement retailers were surveyed. Vitamin D content was determined from manufacturer’s websites and product packaging.

Results 67 multivitamins were surveyed, containing 0–800 IU/day vitamin D. Only 25%–36%, depending on the child’s age, provided ≥400 IU/day vitamin D. Supplements containing only vitamin D or labelled as for ‘healthy bones’ typically had higher vitamin D content (57%–67% contained ≥400 IU/day).

Conclusions Few multivitamin products supply the recommended 400 IU/day vitamin D. Clinicians need to be aware of this when recommending vitamin D supplementation and advise parents/carers to choose a product that contains ≥400 IU/day vitamin D.