Vitamin D3, or cholecalciferol, is essential for the proper functioning of our body and plays a decisive role in the quality of bone tissue. It is provided by food (dairy products, fish, eggs) and is produced by skin exposed to the sun. However, more than 1 in 3 French people fail to meet their physiological vitamin D3 needs, which is a major public health concern. Indeed, a vitamin D3 deficiency exposes people to known risks for human health, in particular during periods of growth. Pediatric societies recommend routine vitamin D supplementation for children to prevent rickets and for the elderly to avoid osteoporosis.