Last Updated on May 2, 2025 by Giorgia Guazzarotti

4 reasons why you should not make a DIY vitamin C serum

“How can I make my own DIY vitamin C serum, Gio? I’m tired of spending a fortune on products that go bad before I have time to finish the bottle.”

I hear ya. Vitamin C is a skincare superhero with plenty of anti-aging superpowers. Studies show it:

But it’s finicky AF. Goes bad quickly. Costs a pretty penny. Making your own can save you a lot of money, time and hassle…

Or not?

Here’s the deal: L-Ascorbic Acid (the pure form of Vitamin C) is one of the trickiest ingredients to formulate with. You can’t just add a sprinkle of vitamin C powder to your moisturiser and expect it to work. It’s more complicated than that.

Here’s why I think a DIY vitamin C serum with L-Ascorbic Acid isn’t the answer for most people:

1. Wrong Carrier = No Antioxidant Properties

A lot of DIY recipes tell you to dissolve either vitamin C tablets or L-ascorbic acid (the pure form of vitamin C) powder in water. That’s useless.

Watching those vitamin C crystals dissolve is so satisfying and makes you think it’s working. But when you apply the mixture on your skin, vitamin C recrystallizes. Crystallized vitamin C can’t penetrate skin. And if it can’t do that, it won’t work as an antioxidant.

You could fix this by using a carrier that enhances penetration. Alcohol is the most common, but it’s drying for some people. Propylene glycol or glycerin are much better choices. But they too have their limitations.

This solution (l-ascorbic acid + glycerin or propylene glycol) would be water-soluble. That means it won’t be able to penetrate the lipid-based barrier of your skin very well. It’s true that L-Ascorbic Acid won’t dissolve in oil, so you’re kinda stuck with a water-based solution and all its limitation. That’s why it’s important to choose a carrier that enhances penetration.

Making your own DIY Vitamin C serum isn’t just about mixing some powder with water. You need to mix them in a way that gives Vitamin C the best chance of success.

Related: Is Alcohol In Skincare Good Or Bad?

tetrahexyldecyl ascorbate vitamin C derivative

2. Wrong Ph = Irritated Skin

If you think getting the carrier right is tricky, wait till you hear this. Because L-Ascorbic Acid is acidic, it penetrates skin better at an acidic ph (lower than 3.5). When mixed with water at a 5% concentration, L-Ascorbic Acid has a pH between 2.2 and 2.5. That means it’ll work well, right?

Not exactly. The skin’s natural pH is around 5.5 or 6.5. Using a product with a pH too low can irritate it and dry it out. That’s why most commercially available vitamins C serum are formulated at a pH between 2.8 and 3.4.

That’s low enough for vitamin C to work, but not so low to cause irritations (unless your skin is super sensitive). A homemade vitamin C serum is more likely to have a pH that’s too low and that can cause irritations. If you decide to go down this route, have pH strips at the ready to check the pH of your serum.

Related: What The Heck Is The Acid Mantle And How Do You Repair It?


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3. Wrong Storage System = Quick Spoilage

L-Ascorbic Acid is highly unstable. It oxidises, and loses a bit of its effectiveness, every time it’s exposed to light, heat, and air. You’ll notice when your vitamin C serum has gone bad. It turns a brown.

If you want your DIY vitamin C serum to last more than a couple of days, you need to stabilise it. You can do this in two ways:

You’ve guessed it, both solutions are hard to implement at home. The best you can realistically do is make a small batch, pour it into an opaque, airtight container, and store it in the refrigerator. Even then, it won’t last you more than 3/4 days. Are you willing to make a new batch that often? If the answer is not, a DIY vitamin C serum isn’t for you.

HOW LONG DOES DIY VITAMIN C SERUM LAST IN THE FRIDGE?

Honestly? 3 to 5 days if you’re lucky. Even if you keep it in a dark glass dropper bottle in the back of your fridge like a skincare squirrel, oxidation is gonna catch up with it fast. That’s why most commercial brands go through hell and back with stabilizers and testing before they hit shelves.

Related: How To Store Your Homemade Skincare Products

types of vitamin c used in skincare

4. Fewer Ingredients = Fewer Benefits

Most DIY vitamin C serums are pretty simple. L-abscorbic acid. Water. Glycerin. Done. That’s cool. But not enough. I prefer my vitamin C serums to come packed with other antioxidants. Why?

Antioxidants work better together than alone. Studies show that pairing vitamin C with ferulic acid and vitamin E, for example, makes each antioxidant more effective and doubles photoprotection. Sure, you can buy a bunch of antioxidants for your DIY vitamin C serum. But every ingredient you use adds a new layer of complexity to the mix. It changes the pH, may clump or just be unstable.

Related: 5 Things You Need To Know About Antioxidants

Can You Use Vitamin C Tablets Instead of L-Ascorbic Acid Powder?

Technically, yes. Should you? Probably not. Tablets often contain fillers, binders, and other ingredients your skin doesn’t need (or want). Even if you grind them down, you can’t be sure how much actual vitamin C you’re getting—or how your skin’s going to react to everything else in the mix. So the same issues above still apply.

How Much Vitamin C Should Be in a Serum Anyway?

Most experts agree the sweet spot for effectiveness (without wrecking your skin barrier) is between 10-20%. Anything over 20% won’t absorb better. It’ll just irritate your face for no good reason. That’s why those Pinterest recipes that scream “25% Vitamin C!” are giving red-flag energy. But again, how can you calculate the exact percentage at home? Most DIY Vitamin C serum simply don’t contain enough Vitamin C to do the job well.

What If You’re Doing Everything Right?

Are you a DIY fanatic who loves to spend hours learning the chemistry behind homemade skincare products and wiling to splurge on a few pieces of equipment? Great! It’ll take you some trial and error, but you can make a DIY vitamin C serum that works. Just be aware you’ll have to make a new batch every few days.

Just want to follow a random recipe online because you’d think it’d be fun? Sorry to be the bearer of bad news, but making your own DIY Vitamin C serum is more complicated than that. A lot of recipes you’ll find on Google or Pinterest just don’t work.

If you’re not willing to invest the time and money to make DIY skincare products the right way, do your skin a favour and buy a serum from the shops. You don’t want to buy a bottle of vitamin C, pH strips and co only to find out you can’t be bothered to mix a new batch every few days.

One more thing: how do you know your DIY vitamin C serum works? It’s difficult enough for professionals to assess how well antioxidants work. How can you tell at home? It may just be the brightening effect is due to the acidic exfoliation vitamin C gives you. But its collagen-boosting properties? You can’t assess them at home.

Antioxidants are preventative. So if your vitamin C serum doesn’t work, you won’t find out straight away. Heck, you may be applying something for 10 years only to discover it didn’t help that much!

Is L-Ascorbic Acid the Only Type of Vitamin C Out There?

Nope. There are other vitamin C derivatives like Sodium Ascorbyl Phosphate, Magnesium Ascorbyl Phosphate, and Tetrahexyldecyl Ascorbate. These are more stable and less irritating, but also way harder to get your hands on in raw form if you’re going the DIY route.

Plus, they usually need emulsification or special formulation techniques to actually be effective. So unless you’re in the mood to play chemist for real (we’re talking pH meters, emulsifiers, and a spreadsheet of percentages), these aren’t really practical for homemade skincare.

Related: Best Types Of Vitamin C In Skincare: Which One Is Right For You?

drunk elephant c-firma day serum

Can You Use Vitamin C Serum Every Day?

Yep, if your skin tolerates it. Just remember that consistency beats intensity. Using a 10-15% serum every morning under your sunscreen is gonna do way more for your skin than an aggressive 25% DIY blend you can only use once a week because your face burns off. Go gentle, go often.

What Are The Best Vitamin C Serums?

  • MaeLove Glow Booster ($27.95): The cheapest Vitamin C serum in this list, it does everything the others do, but it contains a citrus extract that may be irritating for sensitive skin. Available at Maelove.
  • Paula’s Choice C15 Booster ($46.75): It’s enriched with Hyaluronic Acid and glycerin to deeply hydrate skin. Available at Cult BeautyDermstorePaula’s ChoiceSephora, and SpaceNK.
  • Skinceuticals CE Ferulic ($169.00): The original Vitamin C serum, it costs an arm and a leg, but it works wonders and delivers what it promises. Available at Dermstore and Skinceuticals.

The Bottom Line

There are many skincare products you scan easily made at home. A vitamin C serum ain’t one of them. If you’re not willing to spend the time and effort to do it right, don’t bother.