If you're seeking a brighter, more even complexion (and aren't we all?), then two of the best active ingredients to try are vitamin C and acids. Both are well-known for giving skin a glow—but fitting them into your skincare routine is where it gets tricky.
Do they have to be applied at different times, or can you use them together? Will one inactivate the other? Which one goes on first? What about wait times?
This tutorial is going to answer all of those questions for you, and more. You will learn what vitamin C and acids can do for your skin, the best ways to incorporate them into your routine, which ingredient to apply first, and how long to wait in between layers.
I've also got a free cheat sheet for you to download at the end of this article!
The Benefits of Vitamin C and Acids for Your Skin
Before we talk about how to apply them, here's why you'd want to use both a vitamin C serum and an acid in the first place.
Vitamin C is a powerful antioxidant, so it protects your skin from premature aging by neutralizing free radicals. It also helps to repair existing damage by normalizing collagen production and blocking excess melanin formation—which means your skin will become firmer, more even-toned and more radiant.
There are two types of vitamin C:
- L-ascorbic acid is the active form of vitamin C, and the most potent. The downside is that it is quick to oxidize in the presence of heat, light and air.
- Vitamin C derivatives—such as sodium ascorbyl phosphate, ascorbyl glucoside and ethyl ascorbic acid—need to be converted into active vitamin C within the skin. While that makes them milder than L-ascorbic acid, they tend to be more stable.
Acids are chemical exfoliants that loosen and peel away dead skin cells. This gives an immediate brightening effect, since dead cell build-up absorbs light instead of reflecting it. Over time, acids also help to remove dark spots, reduce fine lines and acne, and even increase firmness.
There are two main types of acids:
- AHAs (alpha-hydroxy acids) exfoliate the surface layer of the skin. Glycolic acid and lactic acid are the most common and effective AHAs.
- BHAs (beta-hydroxy acids) exfoliate the skin surface as well as deep inside the pores. Salicylic acid is the most common and strongest BHA, while betaine salicylate is an increasingly popular gentle alternative.
Both vitamin C and acids are superior ingredients for addressing dullness and discolourations, but they work differently. So pairing them together can give you better results versus using either one on its own.
The only catch? You need to apply your products at the right time, in the right order.
How to Use Vitamin C and Acids in Your Skincare Routine
Option 1: Apply Them at Different Times of Day
The simplest way to incorporate vitamin C and acids in your routine is to apply them away from each other, at different times of day.
This is a good approach for beginners and sensitive types, since AHAs, BHAs and L-ascorbic acid are all acidic ingredients. By separating them, you're less likely to irritate your skin.
As for which active you put on when, it's up to you.
In the past, most dermatologists have recommended using vitamin C serums in the morning. Dr. Neal Schultz, however, believes that a nighttime application is even more beneficial. Away from UV light, the vitamin C "gets fully absorbed into your cells where it's really needed," he told Vogue.
Acids can also be used at any time, as long as you're protecting your skin with a good sunscreen during the day. BHAs have some photoprotective properties, so they're ideal for mornings, while AHAs make your skin more sun-sensitive, so they're your best bet at bedtime.
Option 2: Apply Them on Alternate Mornings or Nights
Another easy option is to alternate between a vitamin C serum and an acid at the same time of day. So, for example, one morning you could apply your L-ascorbic acid, and the next morning, your favourite BHA.
An advantage of this approach is that you're taking it slow, so your skin will be able to gradually adjust to the two active ingredients. It's also a good idea if you have sensitive skin and can't tolerate using acid exfoliants on a daily basis.
But is it enough to be effective? According to celebrity facialist Kate Somerville, yes. "I've seen some amazing results with clients who've added vitamin C into their regimen at three times a week and worked up to daily use," she told