Obagi Professional-C Serum 15% contains With 15% L-ascorbic Acid - the most potent form of Vitamin C - to help calm and brighten your skin whilst retaining moisture, giving you an instant glow. Adding Vitamin C to your skin care regime has many benefits to your skin. Vitamin C stimulates new collagen production, reduces fine lines and wrinkles and protects your skin from harmful free radicals and UV exposure. When used in combination with an Obagi complete skin care system, Obagi Professional-C Serum can help retain moisture and reduce inflammation. Suitable for most skin types.