Vitamin D 

Vitamin D in pharmacy

Vitamin D is a fat-soluble vitamin (soluble in fats: lipids). It is a hormone found in the diet and synthesized in the human body from a derivative of cholesterol under the action of UVB 1 radiation from the Sun.
In humans it exists in two forms: D ₂ ( ergocalciferol ) produced by plants or D ₃ ( cholecalciferol ) of animal origin. These two molecules are 9,10-secosteroids.

Vitamin D is involved in the absorption of calcium and phosphorus by the intestines, as well as in their reabsorption by the kidneys under the influence of PTH. Its effects are counterbalanced by calcitonin. It is involved in bone mineralization of the skeleton and joints, as well as muscle tone.