Widespread fascination with vitamin D as a panacea for most illnesses, including cardiovascular diseases (CVD), is responsible for nearly a 100-fold increase in vitamin D testing and oral supplementation over the last decade, largely in populations at low risk for vitamin D deficiency.1 Assessment of vitamin D levels is the fifth most commonly ordered laboratory test in the United States, with an estimated annual cost of approximately $350 million. This testing was facilitated by the advent of mass spectrometry for accurate and reproducible measurement of serum 25-hydroxyvitamin D (25-OH D), which has a long half-life and reflects both dietary intake and cutaneous synthesis vitamin D.2 The popularity of vitamin D supplementation is at least partly owing to the misinterpretation of impressive epidemiologic associations between vitamin D status and a breadth of health metrics, leading to a potentially flawed assumption of causality.