How is Vitamin A1 otherwise known?

Vitamin A1, also known as Retinol, is a vitamin found in food and used as a dietary supplement. As a supplement, it is used to treat and prevent vitamin A deficiency. In areas where deficiency is common a single large dose is recommended to those at high risk a couple of times a year.

It is also used to prevent further issues in those who have measles.

Retinol at normal doses is well tolerated. High doses may result in an enlarged liver, dry skin, or hypervitaminosis A. It is converted in the body to retinal and retinoic acid through which it acts. Dietary sources include fish, dairy products, and meat.

Retinol was discovered in 1909, isolated in 1931, and first made in 1947. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system.