The active form of Vitamin A that regulates many cell activities.

a form of vitamin A that stimulates rapid cell turnover and is used to treat severe acne. Tretinoin gel is an experimental treatment for Kaposi's sarcoma.

Vitamin A acid typically used in products for the treatment of acne and certain signs of photodamage.

(REH-tih-NOH-ik ASS-id) A form of vitamin A that is made by the body, and can also be made in the laboratory. It is used to treat acute promyelocytic leukemia, usually together with other drugs, and to treat acne. It is being studied in the treatment and prevention of other types of cancer. Also called all-trans retinoic acid (ATRA), tretinoin, and vitamin A acid.

the cis-trans form of vitamin A. Retinoids act as a mild chemical peel on the skin and are very important to all epithelial structures