If you’re not ready to give up your dedicated vitamin C serum, will a cheap alternative work? “In my view, you tend to get what you pay for,” says Dr. Hextall. “If you are looking for an effective, stable vitamin C serum with a powerful antioxidant formulation, it isn’t going to be your cheapest purchase.” She always advises her patients on where they should splurge and where they can budget. As UV and pollution are the most damaging aggressors to our skin (causing around 80% of visible damage and photoaging) potent antioxidants like vitamin C, not to mention high factor, broad-spectrum sunscreens are key and worth the investment, says Dr. Hextall. In her experience, cheap vitamin C serums have proven ineffective or are formulated at unnecessarily high concentrations that are acidic and irritating to skin. They are subsequently often abandoned by users, says Dr. Hextall, which is money down the drain.