Murad's Retinol Youth Renewal Serum helps quickly & visibly minimize lines & wrinkles, firm, even skin tone & boost radiance for more vibrant, youthful skin. It's clinically proven: Users in a single-blinded study reported visible improvement in the key 5 signs of aging: Fewer lines and wrinkles, skin that looks firmer, feels smoother, and is more even-toned with a boosted glow (after 4 weeks).