Introduction: Hypovitaminosis D is highly prevalent and constitutes a public health problem worldwide. It can affect more than 90% of individuals, depending on the population studied. Objective: To make a broad analysis of the world literature to compose the State of the Art on serum vitamin D levels and its adequate supplementation, to prevent and mitigate various diseases, based on randomized clinical studies, analysis, and latest international conferences and consensus. Methods: The present study followed a literary review of randomized clinical studies, meta-analysis, and the latest international consensus. Cochrane instrument was adopted to assess the quality of the included studies between 2015 and 2020. Major considerations and conclusion: Laboratory evaluation should be performed by measuring 25(OH)D, and the main groups of individuals at risk for vitamin D deficiency are the elderly, patients with osteoporosis, history of falls and fractures, obese, pregnant women, and infants. For patients with osteoporosis and increased risk of fractures, recommended that concentrations of 25(OH)D remain above 30 ng/mL for full benefits on the prevention of secondary hyperparathyroidism, decreased risk of falls. Special considerations must have taken to pregnant women and infants, in patients with chronic renal failure, obese patients, and those undergoing bariatric surgery. Several clinical studies and current meta-analysis have shown significant results with vitamin D supplementation in cardiovascular complications, diabetes, cancer, autoimmune diseases, cognitive function, among others, with doses above 30 ng/mL, reaching up to 70 ng/mL, and maintaining serum dosage at 50 ng/mL.