StriVectin's breakthrough formula delivers the promises of retinol without the irritation. NIA-114 molecule (Niacin), used in the product, is a form of vitamin B that is clinically proven to help strengthen the skin barrier, reducing nearly all the sensitivity and irritation associated with retinol use. After usage you'll notice fine lines are reduced, an even complexion and a smoother, more radiant texture.£170 per 100.00ml