Vitamin D3 is an active antirachitic factor.  

Vitamin D promotes the absorption of calcium and phosphates in the intestine, the transport of mineral salts and calcification of bones, and also regulates the excretion of calcium and phosphates by the kidneys. Vitamin D3 ensures the normal functioning of bones and teeth, as well as supports the normal function of the immune system and muscles.  

In addition, vitamin D3 plays a role in cell division and maintaining normal calcium concentrations in the blood.