cholecalciferol

Cholecalciferol, also known as vitamin D3, colecalciferol or calciol, is a skin-made vitamin D that is found in certain foods and used as a dietary supplement. It was first described in 1936, and is on the World Health Organization's List of Essential Medicines. In 2023, it was the 68th most commonly prescribed medication in the United States, with more than 9million prescriptions, and is available as a generic medication.

Cholecalciferol is synthesised in the skin following sunlight exposure. It is then converted in the liver to calcifediol (25-hydroxycholecalciferol D), which is further converted in the kidney to calcitriol (1,25-dihydroxycholecalciferol D). One of calcitriol's most important functions is to promote calcium uptake by the intestines. Cholecalciferol is present in food such as fatty fish, beef liver, eggs, and cheese. In some countries, cholecalciferol is also added to products like plants, cow milk, fruit juice, yogurt, and margarine.