Isotretinoin is a synthetic stereoisomer of all-trans retinoic acid (tretinoin). The exact mechanism of action of isotretinoin has not yet been determined, but it has been established that the improvement of the clinical picture of severe forms of acne is associated with a decrease in the activity of the sebaceous glands and a histologically confirmed decrease in their size. In addition, the anti-inflammatory effect of isotretinoin on the skin has been proven.