With all good things, there are always risks and side effects! The most common ones that people tend to experience are itchiness, redness, skin irritation, or a cool tingling sensation when applied. Thankfully, the tingling feeling shouldn’t last for very long. Sometimes, it is just your skin getting used to new beauty products. That’s why it’s important to ease into using vitamin C so that your skin can adjust. However, if your skin breaks out in hives or swells, wash the product off your face and stop use. That could be the sign of an allergic reaction. When introducing any new product to your skin, it’s important to test it out first before fully incorporating it into your everyday routine. Start with a lower concentration of vitamin C, test out a small amount on your skin, or use your serum every other day to see how your skin reacts. Testing a small amount of product on your skin and waiting 24 hours will allow you to see how your skin reacts and keep you from having a reaction from the serum all over your face. Once you see how your skin reacts, you can make adjustments so you'll get the best results from the products on your face. Generally though, vitamin C serum works for most skin types, so the chances of major side effects or reactions are slim!