After years of neglecting your skin, you want to reverse effects that built up over time, including lines, wrinkles, sun spots, and damaged skin cells. Research points you in the direction of vitamin C serum, and you take a close look at possible options to help your skin. Concentrated amounts of vitamin C, such as 10 percent in serum form, help your skin by providing ample amounts of the natural vitamin, which the skin loses over time. This vitamin works particularly well for fighting wrinkles, producing collagen for enhanced skin elasticity. A vast inventory on eBay includes 25 percent vitamin C serum with wrinkle-busting protein that keeps the skin firm and youthful. In some cases, serums offer up to three times wrinkle reduction, or other anti-aging properties. There are serums that work well in conjunction with other skin products to assist tired and stressed skin. Depending on the specific vitamin C serum, you may need to keep it refrigerated after opening for maximum results. Special ingredients may include ferulic acid, a potent antioxidant that protects the skin from UV damage, and radish root, a natural preservative.