Oral calcidiol is a good form of vitamin D supplementation.

Vitamin D supplementation represents an important topic in the field of metabolic bone disease. Calcidiol, the 25-hydroxy-vitamin D [25(OH)D], is the form of vitamin D most recently introduced in clinical practice. Advantages of the use of calcidiol derive from the pharmacokinetic properties and are related to the possibility of use in patients with liver disease, obese patients, patients with intestinal malabsorption, secondary hyperparathyroidism associated with chronic kidney disease as well as to avoid any possible toxic effect when high doses are used. The ADDI-D study demonstrated the efficacy and safety of calcidiol at the daily dose of 20 or 40 μg and 125 μg/week. In particular, the daily dose of 40 μg can be suggested as an alternative in severely deficient patients, as it has demonstrated to ensure higher vitamin D levels, compared to the 20 μg/day and the weekly 125 μg dose. The last can be an option when issues with compliance to the supplementation are present.