Perez-Castrillón JL, Duenas-Laita A, Brandi ML, et al. - A one-year, phase III-IV, double-blind, randomized, controlled, multicenter clinical trial was designed to evaluate the efficacy and safety of calcifediol 0.266 mg soft capsules in vitamin D-deficient postmenopausal women, compared to cholecalciferol. Researchers enrolled a total of 303 patients, of whom 298 were included in the ITT population. Individuals with baseline levels of serum 25(OH)D < 20 ng/mL were assigned randomly in a 1:1:1 ratio to calcifediol 0.266 mg/month for 12 months, calcifediol 0.266 mg/month for 4 months followed by placebo for 8 months, and cholecalciferol 25000 IU/month for 12 months. These outcomes therefore validate that calcifediol is effective, faster and more potent than cholecalciferol in raising serum 25(OH)D levels and is a valuable option for the treatment of vitamin D deficiency.