When should you use vitamin C serum—morning or night?

When is the best time to apply your vitamin C serum, morning or night? It's likely a question that most vitamin C users have turned over in their head at one point or another, as we all know that vitamin C isn't the most easygoing of ingredients. 

There's no doubt that adding one of the best vitamin C serums to your routine is one of the keys to unlocking great skin. If kept out of direct sunlight, it works to protect skin against free radicals and other damaging environmental factors like pollution and UV, while helping to encourage skin cells to produce collagen—which will leave your skin radiant, plump and free of any fine lines or wrinkles. It is also famed for inhibiting the production of melanin so helps to fade discoloration and dark spots.

But, seeing the very best results on from using vitamin C could all come down to our timing. Because it turns out, that there is a better time to use it during the day—so when should we be incorporating it into our routines, morning or night? Our contributing beauty expert has broken down the benefits of both ways, to help you make an informed decision based on what’s right for your skin type, so that you soak up all the endless benefits of vitamin C as much as possible.

When to use vitamin C serum—morning or night

To properly answer this question, it's important to explore the benefits of using your vitamin C serum in the morning, and in the evening, to help you work out when its application make be most helpful to you and your skin type.

How to use vitamin C in the day and its benefits

Found in products like La Roche-Posay Pure Vitamin C10 Serum, vitamin C is one of the most powerful antioxidants out there. "The benefits of topically applied Vitamin C are numerous," says chemist Bruce Green (opens in new tab) of SOS Serum (opens in new tab). "Not only does it play a vital role in the production of pro-collagen—the building blocks of collagen fibres—it also helps control hyperpigmentation, scavenges free radicals, strengthens capillary walls and helps heal damaged skin, helps boost the skins natural immune system and it can help the skin to look brighter and also help to prevent the signs of premature ageing."

Once you've nailed how to use vitamin C serum properly, it really comes into its own during the day. If applied in the morning, it can get to work throughout the day protecting skin against harmful elements like pollution, free radicals, UV rays, and other factors that can leave skin looking dull and lifeless. 

If you are using your vitamin C serum during the day, it should always be followed by one of the best sunscreens for face—preferably with SPF 50, but at least a minimum of SPF 30—to help protect skin against the sun. 

However, if your skin is super sensitive and prone to irritation, applying a strong vitamin C in the morning may not work for you. You could either use a gentle antioxidant during the day and switch to using vitamin C at nighttime instead. Or, you could opt for a lower strength vitamin C serum which is less likely to cause any sensitivity or reaction. 

How to use vitamin C at night time and its benefits

While you’re sleeping, your skin undergoes its natural repair process. During sleep, your skin’s blood flow increases, and it rebuilds collagen and repairs damage like fine lines, wrinkles and age spots that have been caused by UV exposure. So using vitamin C serum during the night means that it's likely to have the most effective impact when it comes to repairing your skin.

If your chosen serum is quite potent, like the Medik8 Super C30 Intense, you also reduce the risk of photosensitivity occurring (a reaction that can be triggered by sunlight) if you use it during the nighttime.

It’s worth adding that if you do choose to use vitamin C at night, you should always still ensure you’re using SPF the following day, to ensure maximum efficacy.

Benefits of using vitamin C in the morning *and* the evening

Think of slathering vitamin C in the morning and the nighttime as the best of both worlds. You get to reap the rewards of vitamin C's powerful antioxidant properties by essentially getting a double dose.

One thing that you need to consider though, is that the skin has a limit for absorbing vitamin C. 

In other words, once this limit has been reached, any extra product is essentially wasted (and it doesn't come cheap). So if you’re using a product that’s more gentle and has a lower percentage of vitamin C in it—like the La Roche-Posay Pure Vitamin C10 Serum—you’re good to use it twice a day. But if your chosen serum has a higher, more potent level in it, then it’s best to adopt a less is more approach and stick to using it just once.

"Formulation matters, particularly with vitamin C as the active ingredient is relatively unstable and in time, the vitamin C becomes less “active”," says NHS dermatologist, Dr Bernard Ho (opens in new tab). "I would suggest looking at the manufacturers or product details as it will tell you how long they expect your vitamin C product to last and when to use it up by."

So should you use vitamin C in the morning or night?

While it’s all down to your skin (and no one knows your skin better than you), most people prefer to apply vitamin C serums in the morning because of its antioxidant properties—which means it'll help to defend your skin against pollutants and free radicals that could otherwise damage it throughout the day. However, never forget to follow with SPF to protect your skin against the sun.

But, if your skin tends to be on the sensitive side, then using vitamin C at nighttime is advisable. And if you want to really make the most out of the restorative properties of the product, nighttime use of vitamin C might also be preferable, as it will have a bigger impact on your skin as it performs its nightly repairing process.

However, just be careful if you use both retinol and vitamin C in your skincare routine. "I would suggest not layering vitamin C with retinol as it can cause irritation when used at the same time," advises Dr Ho. "I would suggest pairing with or looking for a vitamin C product that combines other hydrating ingredients such as glycerin and hyaluronic acid instead."