Fantastic product !! Put on clean face in evening, I use Neutrgena Deep Clean Scrub. This serum feels great, slight tingle. Gentle tightening sensation. I can feel it working. I have dry, fair, sensitive skin. NO negative side effects. My neck & face are glowing, lines fading. Deep Lines less. The Deep Wrinkle Serum has almost erased lines around top lip and corners of mouth. I have tried several different Age reducing products, NONE as affordable as Neutrogena, none this effective !!!!