Vitamin C, also known as ascorbic acid, is a water-soluble vitamin that fades dark spots and hyperpigmentation, brightens the complexion and provides antioxidant protection against environmental damage. Vitamin C is also used in anti-aging products to promote collagen production and improve skin texture and firmness. It's also important to choose vitamin C products with stable formulas and appropriate concentrations for optimal benefits. Vitamin C is sensitive to light and air exposure, so products should be stored properly to maintain their effectiveness.