During the Autumn and Winter months, with reduced sun exposure, studies suggest that vitamin D levels decrease. This may lead many people to rely on dietary sources or supplements for their vitamin D intake during several months of the year. While some individuals may not show any physical signs of deficiency, others may experience a variety of physical symptoms. This course aims to explore the causes of Vitamin D deficiency, treatment options available for both asymptomatic and symptomatic individuals, medical indications for vitamin D use, as well as when to test and refer.