Blood orange on marble table

So…What Does Vitamin C Actually Do for Your Face?

Every time I catch a cold, my mom reminds me to take Vitamin C. And then, she supplies me with a Costco-sized carton of oranges.

There’s no doubt that Vitamin C is a powerful antioxidant. But despite what your mom tells you, your body can only absorb so much at any given time. And what you absorb doesn’t always reach your skin.

That’s where topical serums come in.

Read the rest of the article to find out how these serums work.

Vitamin C Serum Benefits

Vitamin C serums are trending right now.

I know, I know—most popular skin care products don’t actually live up to the hype.

Fortunately, that’s not the case with Vitamin C. These serums are packed with a whole slew of benefits that’ll ward off the aging process (yay!).

1. Protects Your Skin From Harmful UV Rays

You’ve probably heard horror stories about UVA and UVB rays. Heck, even my teenage cousins won’t leave the house without slathering on a big glob of sunscreen.

And, don’t get me wrong, sunscreen is great—I wouldn’t leave the house without it either. But, when you use Vitamin C in conjunction with sunscreen, you’re adding an extra layer of protection to your skin’s barrier.

Some studies have found that Vitamin C actually reduces the formation of sunburn cells (aka UVB damage) in pig skin (2). Since sunburn cells increase your risk of skin cancer, reducing the presence of these cells can reduce your risk.

In regards to UV damage, Vitamin C isn’t the only thing you should use. One study tested Vitamin C + Vitamin E + Ferulic Acid and found that this combo provided excellent protection against some skin cancer mutations (3).

One more thing.

Since Vitamin C is great for treating redness, using it after a sunburn will supercharge your recovery.

2. Fights Free Radicals

As I already mentioned, Vitamin C is a powerful antioxidant.

But, what the heck does that mean?

Well, to understand antioxidants, let’s first take a look at free radicals.

In a scientific sense, free radicals are chemicals with one or more unpaired electrons, making them unstable and potentially toxic.

Their presence isn’t necessarily a bad thing. As it turns out, they play a part in normal biological functions. And your body has a pretty good way of neutralizing them naturally.

Free radicals start to pose a threat when they outweigh antioxidants. And unfortunately, there are tons of stressors that can tip the scales. These stressors include:

  • Alcohol consumption
  • Pesticides
  • Pollution
  • Radiation
  • Smoking
  • Emotional stress
  • UV exposure

When free radicals outweigh antioxidants, they cause cellular and oxidative damage. Among more serious diseases, this can lead to things like wrinkles, brown spots, and premature aging.

Now onto antioxidants.

Antioxidants are like molecular vigilantes. They seek out free radicals in an attempt to stabilize them. This stalls oxidation, thereby saving your skin and/or body from potential damage.

It’s a hard thing to visualize, so let me try to explain the role of free radicals and antioxidants in a more concrete way.

If you’ve ever sliced an apple (which I’m sure all of you have), you’ve probably seen its flesh turn brown within a matter of minutes. Free radicals—specifically, reactive oxygen species (ROS)—have overtaken your snack. And your apple started to oxidize.

Okay now, let’s say that you squeeze a lemon (ahem, antioxidant) on top of your apple. This time the apple didn’t turn brown. The antioxidants are slowing down the oxidation process. Woohoo!

These same antioxidant principles apply to your skin. So to save your skin from things like air pollution, coat yourself in an antioxidant.

3. Brightens Skin & Combats Pigmentation

Nowadays, everyone is looking for a glow-up. To make it happen, most people turn to the masses of highlighters out there. But with Vitamin C, you’re bound to unleash your inner radiance—naturally!

I know some of you are wondering this. And the answer is no. It doesn’t have bleaching effects and it won’t make your skin any whiter. Whatever you do, please don’t let that deter you from going all-in on Vitamin C. Using it is a great way to even out your skin tone and to brighten (not whiten) your complexion.

How does this happen?

Well, one study suggests that topical Vitamin C serums limit the influence of tyrosinase, an enzyme that promotes melanin production (5). Melanin, as it turns out, is the pigment that’s behind things like hyperpigmentation and skin discoloration.

4. Suppresses Collagen Degradation

With everything that you’ve read so far, you probably won’t be surprised to know that it also boasts some seriously awesome anti-aging effects.

I mean, everyone wants to stay younger longer, right? And you can harness the vital power of Vitamin C to do just that. Yippee!

Alright, alright. You might be a little skeptical about the anti-aging claims. I totally get it. Pretty much every other skincare product under the sun tries to convince you that it’ll keep you baby soft.

But, the thing about Vitamin C—more specifically about ascorbic acid—is that it’s an essential part of collagen synthesis. So, unlike some of its rival products, it really can actually make a difference in your skin.

If you’re not convinced, here’s the breakdown.

A double-blind study found that topical applications of Vitamin C effectively increase pro-collagen enzymes (6). That’s, of course, no surprise since collagen stability is dependent on Vitamin C.

Another study found that Vitamin C suppresses collagen degradation as well as MMP-1 production (7).  For reference, MMP-1 is an enzyme that breaks down peptide bonds in collagen. So its suppression is a good thing for anti-aging…a really good thing.

Collagen loss is an inevitable part of aging. But using the right skin care products—whether it’s retinoids or antioxidants—can make a difference.

Different Forms of Vitamin C in Skincare

Vitamin C comparison chart

Here’s the thing. Not all Vitamin C serums are created equal. Instead, there’s Vitamin C in its natural form (ascorbic acid). Then, there are its derivatives (SAP, MAP, etc.).

Sometimes, it can be overwhelming to tackle all the different forms of Vitamin C in one go. So below is a general overview of the most popular ones.

1. L-Ascorbic Acid (L-AA)

THIS is Vitamin C in its purest form. If you have to choose any type of Vitamin C, I’d choose this one. It packs the most punch in terms of benefits. Especially, when it comes to antioxidant benefits. But there’s one caveat that you should be aware of. It’s not a great choice if you have rosacea or sensitive skin.

Pros: Brightens, Best antioxidant in the bunch, Boosts collagen, Protects against UV damage, Penetrates skin

Cons: Unstable, Can be irritating to sensitive skin

2. Magnesium Ascorbyl Phosphate (MAP)

Now, I’d like to introduce MAP. While it’s not as powerful as L-AA, it’s doesn’t irritate skin as much as L-AA either. And, it’s very—and I mean very—stable. So, it won’t expire on you when you’re only halfway done with the bottle. Oh, and one more thing. It packs some serious anti-aging benefits.

Pros: Shelf stable, Great for anti-aging, Hydrating, Reaches deeper levels of your skin than other Vitamin C’s, Ideal for sensitive skin, Brightens, Boosts collagen

Cons: Less potent than L-AA in antioxidant effects, No studies conducted on UV damage

3. Sodium Ascorbyl Phosphate (SAP/STAY-C)

There hasn’t been much talk about acne in this article. Which is strange considering you’re reading a really long skincare post. But here it is, people! Meet Vitamin C’s acne fighter. Sure, its acne claims are mostly anecdotal, but a lot of sufferers stand behind this stuff.

Pro: Shelf stable, Brightens, Acne-friendly, Boosts collagen, Protects against UV damage, Great for sensitive skin

Cons: It’s not as powerful at boosting collagen as L-AA and MAP.

If you need a SAP serum, I highly recommend Mad Hippie’s Vitamin C serum—it made me look like I had a pregnancy glow. Read my full review here.

4. Ascorbyl Palmitate

Ascorbyl Palmitate is an oil-soluble type of Vitamin C (L-AA and MAP are water-soluble). You might have even seen it on an ingredients list—it’s a commonly used preservative. That being said, I don’t think this would be my first choice as far as derivatives go. Even though it’s popular, there haven’t been too many studies about its efficacy.

Pros: Provides protection against UV damage, Less irritating than L-AA, Boosts collagen

Cons: Unstable, Lack of research, Absorption depends on the formulation, Potentially toxic (9)

5. Tetrahexyldecyl Ascorbate (ATIP)

Like Ascorbyl Palmitate, tetrahexyldecyl ascorbate is another oil-soluble derivative. And, by all accounts, it’s faster at penetrating the skin than any other form of Vitamin C.

Pros: Shelf stable, Penetrates skin (fast!), Skin brightener, Provides protection against UV damage, Boosts collagen, Great for sensitive skin

Cons:  Lack of research

Choosing the right Vitamin C for your skin is a matter of preference. Not to mention, it’s a matter of trial-and-error. You might have to go through a few products with a few different formulations in order to unleash your holy grail.

Can Vitamin C Be Absorbed Through the Skin?

Skin can’t absorb L-AA at a pH that’s higher than 3.5 (8). So, to mitigate the risks of an off-balance pH, you should buy your product from a manufacturer that’s trusted in the skincare industry. With the right formulation, your skin will have no problems absorbing L-AA.

Some derivatives suck at the absorbing thing. (I’m looking at you Ascorbyl Palmitate!).

While others are masters of absorption.

Take MAP, for example.

MAP is hands-down the best absorber of the bunch. It penetrates deep into the layers of your skin. And provides an extra boost to the cells in those deep layers. Maybe that’s what makes it such a great anti-aging tool.

What You Need to Know About Vitamin C Serum Oxidation (L-Ascorbic Acid)

You might be gearing up to get your Vitamin C fix ASAP. These serums are great. Really, they are. But, there’s one little thing that can get a little…annoying.

And that thing is stability.

Like I said before, L-AA is the most potent type of Vitamin C, but it’s also the most fragile. Exposing L-AA serums to air, light, and/or heat will speed up the oxidation process, making it unstable and unusable.

The good thing is that you don’t have to wonder if your serum is past its prime. It’s pretty easy to tell. L-AA is water-soluble. So, when the serum is still good, it should be clear. Completely clear, like water. And, when it’s “bad,” it’ll start turning yellow.

Here are a few tricks you can use to either slow down the oxidation process.

  1. Only buy serums in dark bottles (UV protection!).
  2. Keep your serums in the refrigerator, unless the bottle specifies otherwise.
  3. Tightly seal your serum’s lid after every use.
  4. Buy travel-sized products.
  5. Ditch L-Ascorbic Acid for more stable derivatives.

But, what the heck happens when serums go bad anyway?

Well, it loses its potency. So, when you apply the oxidized serum on your face, you won’t be getting the maximum antioxidant, anti-aging, and anti-pigmentary benefits that you would with a non-oxidized serum.

I don’t know about you, but I’m not comfortable applying an expired and stinky serum to my face. So when it turns dark yellow, I would throw it out and buy a new serum.

If this oxidation stuff freaks you out, you can always opt for one of Vitamin C’s stable derivatives like MAP (Magnesium Ascorbyl Phosphate) or SAP (Sodium Ascorbyl Phosphate).

Vitamin C Serum Side Effects

You’re not going to find anything too wild in this section. That’s because Vitamin C serums are, by most accounts, safe to use.

Unsurprisingly, the biggest concern is related to the pH of L-AA. To give you an idea of what we’re working with here, the pH of L-AA is 3.5 and the pH of your skin usually sits at a cool 5.5.

Because the pH of L-AA is so low, it can cause redness, stinging, over-exfoliation, and general irritation for sensitive skin types.

Instead of going with a full-fledged 20% concentration, start slow. Start with a 5% concentration and work your way up.

But if you have sensitive skin, choosing a derivative is probably your safest bet. Derivatives, like MAP and SAP, generally won’t irritate your skin.

Best Vitamin C Serums

  • Mad Hippie Vitamin C Serum. In terms of antioxidant serums, THIS is my holy grail! There are tons of reasons why I’m in love with it. For starters: it’s affordable, has a long shelf like, it’s hydrating (thanks to ingredients like glycerin and hyaluronic acid), it makes me look like I’m glowing, and the list goes on.
  • Klairs Freshly Juiced Vitamin C Serum. If you’ve never used L-AA before, starting with a 20% serum might be irritating. This serum contains 5% L-AA, so it’s a great place to start if you’re a newbie with sensitive skin.
  • Timeless Vitamin C + E Ferulic. If you need an L-AA serum with a little more oomph, try this 20% one by Timeless. It’s biggest claim to fame is that it’s a budget-friendly dupe for the triple-digit-pricetag Vitamin C serum by Skinceuticals.

Read More