Dr. Barbara Sturm’s The Good C Vitamin C Serum deploys her proprietary formulation of Vitamin C in an optimal concentration of 5% that’s stable, easily absorbed and gentle on the skin. It contains an active ingredient complex that includes oil-soluble Vitamin C THD, plant-based Vitamin C and stabilized, synthetic Vitamin C in glucosidic form. Together, they help to reduce uneven pigmentation, improve tone and provide anti-oxidative protection from free radicals and environmental stressors for a youthful and healthy-looking complexion. The serum also contains Zinc, which helps to increase the absorption of Vitamin C into the skin. Finally, Vitamin C supports the formation of collagen, which is needed for firm and youthful-looking skin.