OSEA Hyaluronic Sea Serum. This fast-absorbing, anti-aging serum is clinically proven to smooth the appearance of all lines and deliver a lifted, firmer look. Two molecular weights of hyaluronic acid, seaweed and snow mushroom, work together to restore and maintain optimal moisture levels, keeping your skin hydrated, plump and dewy any time of day. Clinically and dermatologist tested. NWOT. Never used!