How to Use a Vitamin C Serum

Medically reviewed by Anna H Chacon, M.D. FAAD 
Vitamin C is the skincare superhero

Vitamin C is a glow-enhancing, protective ingredient that’s basically a must in any optimized skincare routine. We like to think of it as the friendly neighborhood superhero of skincare!

It actively fights off and neutralizes the most menacing skin-emies, repairing any and all damage they cause and defending against future attacks.

But how to use a vitamin C serum to ensure you achieve the best possible effects? That’s what this guide is all about!

What is vitamin C and how does it work?

Vitamin C, at least in its proper, bioavailable form as ascorbic acid, is a powerful antioxidant that gives the skin a renewing and protective boost.

You probably already know how important it is in your diet, but when applied topically, there’s so much that vitamin C serums can do for your skin.

Vitamin C can brighten your skin, even out your skin tone, protect you from external damage that leads to premature aging, and even improve existing fine lines and wrinkles.

In the short term, it also gives the skin a glow like no other!

That said, to experience all of these benefits, it’s important to choose an actually effective vitamin C product.

A lot of so-called vitamin C products are made with derivatives that don’t offer the same benefits or they’re packaged in a very unstable way that leads to vitamin C degradation. Check out our guide to choosing a vitamin C serum to make sure you pick up a product that’ll actually work.

When should I apply my vitamin C serum? Day or night?

There’s a lot of confusion about when to apply vitamin C. Is a vitamin C serum better at night or during the day?

Because of its powerful protective abilities, it’s best to apply vitamin C serum in the daytime, as part of your morning routine.

Vitamin C neutralizes the destructive, aging damage caused by the sun and pollution. That’s why you want it on your skin in the daytime, when you’re more likely to spend time outdoors coming face to face with all of these external aggressors.

Plus, vitamin C’s powerful antioxidant abilities also mean it can keep your sunscreen a little more stable, so it’s a nice boost to your sun protection efforts.

That said, if vitamin C doesn’t fit into your morning routine for whatever reason, rest assured that it’s still effective even if you use it at other times of the day.

Using a correctly-formulated vitamin C serum for a few days in a row raises the level of vitamin C in your skin. That means you’ll benefit from it in the daytime even if you applied it at night.

How to use a vitamin C serum, step-by-step

Here’s how to use a vitamin C serum in conjunction with the rest of your skincare routine!

Step 1: Start clean and refreshed

Before applying your vitamin C serum, start with clean, fresh skin. In the morning, we suggest you just splash your face with water. If you’re feeling dehydrated, take your time to soak your skin thoroughly, instead!

Do you have to cleanse your skin before using vitamin C? We don’t think so, especially if you’re using a vitamin C serum as your daytime protector. You can wash your face if you feel like you need to, but it’s not mandatory (and overwashing can actually be very irritating!)

Step 2: Apply your serum

With your skin still damp, apply your vitamin C serum.

You don’t need much - with the Protocol Vitamin C Superserum, a single pump is enough for the face, neck, and maybe even your chest or back of your hands (all of which deserve the extra love!).

Dispense a bit of serum in your hands, and then massage or pat it in gently. Rubbing can feel nice and stimulating, but “tapping” it in is better if your skin is feeling sensitive.

Step 3: Add needed moisture

Once the vitamin C sinks into your skin, you get to decide for yourself - do you want to moisturize?

We’re big believers in listening to your skin. Maybe your nighttime routine is already super moisturizing, or perhaps your sunscreen is creamy and hydrating. If that’s the case, dive straight into the final step.

On the other hand, if you often wake up feeling a little tight and dry, apply a moisturizing serum or cream.

Step 4: Sunscreen is a must

Finally, it’s time for the queen of all skincare routines: Sunscreen! Again, this is assuming you’re applying your vitamin C serum in the daytime.

Make sure your skin has fully absorbed your vitamin C serum and other products you’ve used. Otherwise, those other products may compromise your sunscreen’s film-forming abilities.

To get the full level of protection, use at least 2 mg of sunscreen per square cm of skin. That works out to about a ¼ teaspoon for the face. Massage it in, and voila - you’ll be ready to face the day, with your SPF bolstered by your vitamin C!


Can I use vitamin C serum every day?

Yes! In fact, you need to use it for a few days in a row in order to raise your skin’s vitamin C levels and achieve consistent glow and protection.

While irritation from vitamin C is incredibly rare, it’s not completely unheard of. With all active skincare products, we recommend you ease your way in by using it a few times a week. If all goes well, ramp up the frequency to every day.

When should I apply vitamin C serum to my face?

Vitamin C should be the first leave-on product you apply to your face. Otherwise, it’ll struggle to absorb and you’ll miss out on its incredible effects.

That means you should apply your vitamin C serum immediately after cleansing your skin or splashing it with water. Give it a few moments to sink in, and only then apply additional serums, moisturizers, or other leave-on products.

Do I use vitamin C serum before or after moisturizer?

Use your vitamin C serum before your moisturizer, to ensure optimal absorption and maximum benefits!

Can I use vitamin c serum and hyaluronic acid?

Yes! There are no conflicts between hyaluronic acid and vitamin C so you can use them in the same routine. Apply your vitamin C serum first, and then follow it up with your hyaluronic acid serum or moisturizer.

Can I use vitamin C serum and retinol?

Yes, but probably not at the same time. To use vitamin C serum and retinol in the same overall skincare routine, we recommend using vitamin C in the daytime and retinol at night.

Both of these ingredients are quite powerful, so we think it’s better to let each one shine on its own as the star of your respective AM and PM skincare sessions. This ensures better absorption and maximum results!

Plus, vitamin C serum makes the most sense to use in the daytime, thanks to its robust skin protective abilities, while retinol makes more sense at night when it can take its time promoting skin renewal and transformation.

Can I apply vitamin C serum overnight?

Yes! Your skin will still benefit from vitamin C serum even if you apply it at night.

If you find that, for whatever reason, making vitamin C part of your morning routine isn’t convenient, using it at night is perfectly fine. Your skin will still enjoy its antioxidant protection, and you’ll still see an improvement in skin luminosity and clarity.

Use your vitamin C serum for glowy skin

Vitamin C serum is a cornerstone in our skincare routine. We can’t resist its glow, and we like knowing that it gives our sunscreen a little boost.

As you have probably gleaned from this post, it’s not a complicated product to use!

Slap it on (respectfully) as your first leave-on product in the morning, and everything else can follow suit on top of it.

That’s not to say vitamin C itself is simple. In its pure, natural form as ascorbic acid, it’s a finicky ingredient that degrades easily.

A lot of brands will sell you on a vitamin C serum, promising incredible skin brightening or anti-aging effects, when they’re actually using a vitamin C derivative with minimal effects or research to justify its use.

That’s because formulating it correctly requires a few things: A truly oxygen-free manufacturing environment, an actually airtight bottle, a water-based, acidic formula, and a correct percentage (10% is ideal).

It’s a struggle to meet all of these standards, but it’s mandatory if you want an effective vitamin C serum.

We wanted to know our vitamin C had real benefits, which is how the Vitamin C Superserum came to life. We developed a patented, oxygen-free packaging method that keeps our vitamin C fresh, stable, and ready to set your skin aglow.

Now that you know how to use a vitamin C serum in your skincare routine, you may as well opt for one that you know will work!

Medically reviewed by Anna H Chacon, M.D. FAAD 

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