Pure Vitamin C10 Regenerating Anti-Wrinkle Serum. A unique anti-aging skin renewing serum with a high concentration of pure vitamin C, salicylic acid and soothing neurosensin with the skin's physiological pH, to reveal the full radiance of even sensitive skin. Vitamin C is extremely active, it can react in contact with air and turn yellow. This does not affect its harmlessness or effectiveness. After each use, wipe the inside of the pipette cap well before closing the bottle. Avoid contact with fabrics.