Vitamin D supplementation is a hot topic, both in the scientific literature and in the media, which often portrays it as a panacea for disease. Since 2013, vitamin D has been one of the 20 most commonly prescribed medications in the English NHS. Of the top 20 agents in 2018, vitamin D had the fourth largest increase in both prescriptions and costs since 2008. Testing for vitamin D has also increased. At the same time, the effectiveness of supplements for conditions other than the deficiency diseases rickets and osteomalacia has been questioned. It is therefore important to ask whether the investment by the NHS has been accompanied by improvements in health outcomes and if current guidelines are the best use of resources.