C-Lester Topical Vitamin C20How It Works: The C Lester Topical Vitamin C20 is an intensive Anti Aging serum for dark spots and fine lines. Extremely potent at a 20% strength, the brightening C20 serum carries two different types of pure Vitamin C, known to stimulate the natural collagen synthesis process. A unique formulation of Vitamin C that targets to resolve even skin tone and protection against free radicals. Skin Types: Normal Mature Directions for use: After toner, apply