Everyone who knows about skincare says that you should have a vitamin C serum in your beauty kit–however, they are not always very clear as to why this is necessary. What’s so great about a vitamin C serum that everyone should have one? And how are you even supposed to use it, once you’ve bought it? Today we’re taking a deep dive into the world of vitamin C serums and learning everything there is to learn about these iconic products: from how to use them, to how to store them.
On this post:
- What does vitamin C serum do?
- What to look for in a vitamin C serum
- Different types of vitamin C
- The ideal concentration of vitamin C
- Ingredientes beyond vitamin C
- Finding the best vitamin C serum for your needs
- How to use your vitamin C serum
- When should you use your vitamin C serum? Day or night?
- How often should you use vitamin C serum?
- In which step of your skin care routine should you use your vitamin C serum?
- How much vitamin C serum should you use?
- How long is vitamin C serum good for?
What does vitamin C serum do?
We’ve talked about the benefits of vitamin C many times before: it’s a powerful antioxidant, it brightens the skin, and it boosts collagen production. These benefits make vitamin C an ideal skincare ingredient for anyone a) struggling with dull and tired skin, b) exposed to a lot of environmental aggressions, including sun exposure, c) trying to target the first signs of aging, d) working to prevent and correct dark spots, or e) fighting wrinkles and loss of firmness.
Vitamin C serums provide much the same benefits as vitamin C as a whole: they bring your skin antioxidant protection, a brightening effect, and a collagen-boosting effect. Depending on its specific formula and the other ingredients it contains, some vitamin C serums may focus more on one of these actions: for example, there are vitamin C serums that are promoted almost exclusively to combat dull and tired skin, while others are much more focused on correcting dark spots.
How long does vitamin C serum take to work?
Vitamin C serums, like everything else in skincare, only work if you do. This means, in other words, that your results will depend on how consistently you apply the product. If you apply it daily, for example, you may start to see some results in the first 1-3 months. You may notice your skin looking smoother and more radiant; more complex results, such as improvements in dark spots or skin firmness, may only come later.
What to look for in a vitamin C serum
When looking for a vitamin C serum to add to your routine, you may come across the following question: what makes a vitamin c serum “good”? The internet will be quick to tell you that you should look for this specific form of vitamin C or that specific concentration of vitamin C, but we’re not going to take that approach. Here’s why:
Different types of vitamin C
Vitamin C can appear in your skincare products in many forms–and, therefore, with many names. One of the most common forms, ascorbic acid or L-ascorbic acid, is what many brands call “pure vitamin C”. It’s pretty effective, but it can also be rather sensitizing.
For this reason, there are plenty of other forms of vitamin C derivatives on the market right now, such as ascorbyl glucoside (aka vitamin CG) or ethyl ascorbic acid. We’re not going to tell you some forms are better than others because, to put it plainly, everyone’s skin is different. Ascorbic acid can bring incredible results to one person and, at the same time, wreck the skin of another–it depends!
The ideal concentration of vitamin C
The concentration of vitamin C you should look for in your serum is another controversial topic. As we’ve seen, there are different forms of vitamin C, and 10% of one does not necessarily equate to 10% of another. For this reason, we don’t recommend that you decide which serum to buy based on the percentage of the main ingredient. Indeed, you’ll notice that some brands won’t even tell you how much vitamin C is in their formula–this is not done so you’ll be duped, but so you won’t feel tempted to shop based on concentration alone.
Ingredientes beyond vitamin C
There is one thing we find important when looking for a vitamin C serum though, and that’s the overall formula. What other ingredients besides vitamin C are included in the serum you are considering?
As a general rule, vitamin C works well with other antioxidant ingredients, such as vitamin D (aka tocopherol). A famous ingredient that you will also often find associated with vitamin C is ferulic acid. Vitamin C also works well with depigmenting ingredients like azelaic acid, tranexamic acid, or Thiamidol, and many products contain different combinations of these.
Finding the best vitamin C serum for your needs
After all these considerations, you may be tempted to ask: so what is the best vitamin C serum? We can’t answer that, but we can share a selection of our favorite vitamin C serums. Remember that, at the end of the day, the best vitamin C serum for you is the one that works well on your skin and gives you the results you want. That’s all there is to it!
How to use your vitamin C serum
If you’re going to introduce a vitamin C serum into your routine, you may have some doubts about the best way to use it. To help you, we’ll share some of our best tips in this section:
When should you use your vitamin C serum? Day or night?
Timing-wise, you can use vitamin C both in the morning and evening; however, if you’re trying to reap the antioxidant benefits, using it in the morning under your sunscreen will bring you the best results.
How often should you use vitamin C serum?
You can use your vitamin C serum every day or even, if your skin tolerates it, twice a day, in the morning and evening.
In which step of your skin care routine should you use your vitamin C serum?
For best results, you should use your vitamin C serum as early as possible in your routine. You can use it, for example, right after cleansing your skin (or, if you use a toner, right after toning). Moisturizers should always come after your vitamin C serum. Finally, if it’s daytime, don’t forget to use sunscreen!
How much vitamin C serum should you use?
The amount of vitamin C serum you should use in each application will depend on the product you have. For products that come with droppers, the recommended amount may be anywhere from 2-3 drops to the entire dropper! Make sure to read the instructions on your product to learn about the ideal amount you should be using in each application. For products that come with pumps, the same advice applies: some brands will recommend that you press the pump all the way down, others that you only press it halfway down.
When in doubt, make sure you’re using enough product to cover your entire face and neck, but not necessarily so much that you end up with a lot of excess on your skin. You won’t get better results by using a lot of product!
How long is vitamin C serum good for?
Vitamin C is extremely unstable in skincare formulations. It oxidizes easily when it contact with light or air, and that can tranlate into not only an uglier product (it’ll usually change color) but also a less effective product. To keep your serum from oxidizing for as long as possible, storing your vitamin C serum in ideal conditions should be one of your top concerns when investing in one–especially if you decide to pay serious money for it!
How to store your vitamin C serum
As much as you love having your gorgeous skincare products on display, your vitamin C serum won’t thrive in those conditions. On the contrary, you should store it in a cool, dry, and dark place–like the inside of a cabinet that isn’t in your bathroom.
Whenever you use the product, make sure that you close and seal it correctly, to avoid, as much as possible, the product coming into contact with air.
How long does vitamin C serum last?
To find out how long your vitamin C serum will last after opening, look at the Period After Opening symbol on the packaging (it’s a little icon showing an open jar or pot). There’ll be a number on it, indicating how many months the product will last in good condition after opening.
Based on this, we recommend that you write two dates on your product: the day you opened it and the day it will expire, based on the deadline indicated by the PAO symbol. When the deadline is up, stop using your product.
How to know if your vitamin C serum has oxidized
If you’re worried about oxidation and want to ensure your vitamin C serum is in good condition, keep an eye out for any color changes. Color change is the easiest way to see if your vitamin C serum has oxidized. If the product was white when you opened it but it’s since turned yellow or orange? It’s probably oxidized. Did it start out yellow and it’s since turned brown? Same thing.
And if you’re wondering “but what color should my vitamin C serum be”, that will always depend on the specific formula you buy. You cannot compare the color of different vitamin C serums to each other: you must, rather, compare the current color of your serum with the color it had when you first opened it.
We hope this post has helped you understand how vitamin C serums work. Now that you know how to choose yours, how to use it, and how to store it, you’re all ready to go! Browse our full selection of vitamin C serums in the shop, and find your perfect match!
Beauty Writer & Editor