In creating her new Dr. Barbara Sturm The Good C Vitamin C Serum (£110), Dr. Sturm wanted to provide consumers with a serum that contained the right amount of vitamin C to make a difference in their skin, but without causing sensitivity or damaging the skin barrier. The Good C contains a 5 percent concentration of vitamin C, but made up of three different types of the ingredient: an oil-soluble vitamin C THD (which is an extremely stable form of the ingredient), a synthetic version called vitamin C glucoside, and kakadu plum extract. Together, the three different vitamin C varieties help fade dark spots, improve the overall tone and texture, and protect skin from free radicals caused by external pollution. Dr. Sturm also included zinc, which aids in the absorption of vitamin C, as well as olive leaf extract, aloe vera. hyaluronic acid, and glycerin — all of which help keep skin hydrated and happy.