By Leslie F.
V itamin C serum is the product more people should be trying, some dermatologists say—but there are hints to using it correctly. Here’s how the experts say you can get the best results.Vitamin C is known for keeping our bones strong and supporting great immunity, but it plays an important role in skin health, too. According to research, our skin needs high concentrations of vitamin C to form its protective barrier, produce plumping collagen, and protect against the sun’s damaging ultraviolet (UV) rays. In a nutshell, these effects translate to great skin texture and skin tone. While you should aim to get enough vitamin C in your diet (like with these vitamin C-rich foods), you can also apply a good vitamin C serum directly on your skin for a potentially substantial boost. This topical use doesn’t just help you maintain dewy, healthy skin—it can also target existing wrinkles and unwanted dark spots. When you are choosing poorly packaged products, this impacts the use of vitamin C serum. This is interesting: because light, air, and heat accelerate vitamin C’s breakdown, the right packaging can extend its effectiveness. You should choose a product in darker bottles that block light and try to store it in a cool, dry place. Mixing it with the wrong products can also impact it.
You can also use vitamin C as part of your nighttime routine. UV skin damage continues for hours after sun exposure, suggesting nighttime vitamin C use could help combat these lingering effects. (But again: if you’re using vitamin C serum, wear your sunscreen!)
Still, there are some important caveats. Vitamin C is pretty adaptable so you can use it with most other skincare ingredients. However, steer clear of applying it at the same time as retinoids, benzoyl peroxide, or hydroxy acids, as these combos can trigger skin irritation. (Also, for the safety of your skin, you do not want to be sunbathing while using any of these products.) Even if you don’t have sensitive skin, mixing vitamin C and a retinol product cancels out skin benefits. Vitamin C needs acidity, and the preparations are formulated for this. Retinol needs an alkaline pH—so mixing them means they don’t work to their individual potential.
Also don’t make use of anything past its expiration date. As soon as you open a vitamin C product, make sure you use it. Vitamin C is an “unstable” compound, which means that it breaks down over time. Exposure to air, heat, and light just speeds up this process. So, while product shelf lives vary based on product formulations and ingredients, the average lifespan is about three months once it’s been opened. You need to change out your product before the color goes amber or yellow. This is the tell-tale sign that the vitamin has oxidized and won’t be very effective. Be sure not to miss out on the moisturizer. Using a hydrating moisturizer will help to keep any potential irritation at bay when using vitamin C. But it can also stop your serum from changing color on your skin. Because vitamin C oxidizes when it encounters heat, sun, and air—a common problem people face is having it turn orange on their face during the day. Applying moisturizer (followed by sunscreen) on top of your vitamin C layer will protect it from the elements, avoiding this darkening effect.
Don’t mix it with the wrong products; you can also use vitamin C as part of your nighttime routine. In fact, a 2015 study published in the journal Science found that UV skin damage continues for hours after sun exposure, suggesting nighttime vitamin C use could help combat these lingering effects. (But again: if you’re using vitamin C serum, wear your sunscreen!). Still, there are some important caveats. Vitamin C is pretty adaptable, so you can use it with most other skincare ingredients. However, steer clear of applying it at the same time as retinoids, benzoyl peroxide, or hydroxy acids, as these combos can trigger skin irritation. (Also, for the safety of your skin, you do not want to be sunbathing while using any of these products.) Even if you don’t have sensitive skin, mixing vitamin C and a retinol product cancels out skin benefits. Vitamin C needs acidity, and the preparations are formulated for this. Retinol needs an alkaline pH—so mixing them means they don’t work to their individual potential.
