This product from Cellex-C contains 17.5% vitamin C. Advanced-C Serum has a unique formulation of both hydrolized and free L-ascorbic acid, making it a superior skin rejuvenation product. Powerful anti-oxidants resveratrol, glycine and L-ergothioneine along with grape seed extract are also present to help you achieve faster results. This product is used once daily in the morning. Is not recommended for use around the eyes. Cellex-C Hydra 5 may be applied over the Advanced-C to expedite results. Due to its high potency, do not apply to the hairline or eye brow areas as discoloration of the hair could occur, especially for those individuals with blond or gray hair color. Advanced-C Serum should only be used by those having already using either Cellex-C High Potency Serum, Cellex-C Skin Firming Cream or Cellex-C Skin Firming Cream Plus