How to Use Glycolic Acid and Niacinamide in Your Skincare Routine for Smooth, Bright, Even-Toned Skin

A dynamic duo to get you glowing.

Author:
Michelle Villett
Updated:
May 17, 2024

Glycolic acid and niacinamide are two of the most popular active ingredients in skincare products right now. And it’s no wonder, since they promise to make your skin look smoother, brighter and more even (among many other benefits). So why not incorporate both of them into your routine?

That’s where things can get tricky. Should you mix them together, or look for both in one product? Is it better to apply them in layers? Which one goes on first? And will one inactivate the other?

If you’ve been pondering these questions, this tutorial is for you. Keep reading to learn what glycolic acid and niacinamide can do for your skin, how to use them in your routine, and the best products to consider trying.

What Does Glycolic Acid Do for Your Skin?

Glycolic acid is a chemical exfoliant, and the most well-known alpha-hydroxy acid (AHA). The AHA family also includes lactic, mandelic, citric, malic and tartaric acids, which are all gentler alternatives.^1,2 Glycolic acid is the strongest AHA because it has the smallest molecular weight, which means it easily penetrates the skin.³

Here are the main things it can do:

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Exfoliates dead skin: It breaks down the “glue” that holds dead skin cells together in the stratum corneum (the uppermost layer of our skin). This allows them to be sloughed off, revealing the fresh new skin underneath.⁴
Smooths texture: As little as 5% has been shown to produce a significant improvement in general skin texture after three months.⁵
Brightens and fades pigmentation: All hydroxy acids help with brightening by removing the old dead skin cells that contribute to dull-looking skin. Glycolic acid also improves sun-induced discolourations and sallowness.^5,6
Thickens and firms the skin: By increasing collagen production, glycolic acid can help skin to become thicker and feel firmer.⁷ One study, using a 15% concentration, found that it increased epidermal thickness by 27% after six months.⁸

What Does Niacinamide Do for Your Skin?

Niacinamide is a form of vitamin B3, and it works by giving our skin cells the energy to carry out their functions. That makes it suitable for treating a wide range of skin concerns.

Here’s what it does:

Fades pigmentation and evens skin tone: It has been shown to significantly decrease hyperpigmentation after just four weeks of use.⁹ It can also treat melasma.¹⁰ Another study found that, in combination with provitamin B5 and vitamin E, it significantly improved skin tone evenness in only six weeks.¹¹
Strengthens the skin barrier: It improves the function of the skin barrier by reducing TEWL (transepidermal water loss) and increasing the levels of ceramides and lipids in the skin barrier.^12,13 This leads to a thicker, more resilient stratum corneum that retains hydration and is resistant to damage.^12,14,15
Reduces wrinkles: Multiple studies have demonstrated that niacinamide can treat fine lines and wrinkles. For example, a concentration of 5% significantly reduced wrinkles after 12 weeks, while 4% improved eye-area wrinkles in just eight weeks.^16,17
Smooths texture: As little as 4-5% can produce significant improvements in skin texture.^11,16
Controls excess oil and clears acne: It can also improve oily skin by lowering the amount and rate of sebum excreted.¹⁸ For mild to moderate acne, two studies have found niacinamide to be just as effective as clindamycin, a topical antibiotic.^19,20
Calms redness: Last but not least, it can counteract red, blotchy skin and even rosacea.^16,21

Glycolic Acid and Niacinamide Together

If glycolic acid is your chemical exfoliant of choice, then you should definitely consider niacinamide, too. While each ingredient can produce visible improvements on its own, you’ll get the best results from incorporating the two of them into your skincare routine.

This is because glycolic acid is notoriously irritating, thanks to its low molecular weight.³ For many people, it can cause dry, flaky skin and even redness, stinging and inflammation, especially when first starting treatment. This is expected and (as long as you’re not overdoing it) usually improves as your skin gets used to the acid.

However, niacinamide can help to minimize these potential side effects by making your skin barrier stronger and thicker. It won’t be as vulnerable to irritation, and will become better at holding onto moisture. It will also help to calm down any redness.

Best of all, by using these two ingredients, you’ll be getting double the benefits in terms of smoothing, brightening, fading pigmentation, firming and reducing wrinkles. What’s not to love about that?!

Can You Mix Glycolic Acid and Niacinamide?

Mixing glycolic acid with niacinamide is not a good idea, nor is layering one ingredient on top of the other at the same time. Here’s why:

✗ Decreased Absorption of Glycolic Acid

In order to do their jobs, hydroxy acids are formulated at an acidic pH level. For glycolic acid, it’s typically between pH 3.0 and 4.0.

But niacinamide has a much higher pH, around 6.0. So if you mix the two ingredients together, the niacinamide could raise the pH of the glycolic acid, making it less acidic.

Why is this a problem? One study compared the absorption of AHAs at pH 3.0 and 7.0, and found that the higher the pH level, the less the skin absorbs—and the less activity AHAs have on your skin.²²

✗ The “Niacin Flush”

Besides making your acid less effective, another problem with mixing glycolic acid and niacinamide is that it can cause red, flushed skin.

While niacinamide is meant to be around pH 6.0, acidic conditions can trigger its conversion into niacin, another form of vitamin B3.²³ If you’ve ever taken an oral niacin supplement, then you may have experienced the infamous “niacin flush.” Although harmless, it temporarily makes your skin red, hot and flushed due to the release of prostaglandin D2.²⁴

This has happened to me when I used niacinamide right after glycolic acid, and it’s no joke. My face looked like a lobster, felt very uncomfortable, and the effect lasted one to two hours. Makeup can’t even cover it up!

I believe this may be why some people think they can’t tolerate niacinamide, even though it is one of the gentlest ingredients in skincare. If you’re incorrectly combining it with an acid, it can appear to cause irritation, even though it’s just this temporary “niacin flush.”

How to Use Glycolic Acid and Niacinamide the Right Way

Fortunately, there are several ways to incorporate glycolic acid niacinamide in the same skincare routine. You’ve got three options:

✓ Apply Them in a Single Product

While it’s not advisable to play chemist and mix two separate products, you can use a pre-made product that includes both glycolic acid and niacinamide in the ingredients list. This is because it will be expertly formulated to remain stable and effective at a certain pH level, without causing redness.

The trade-off for the convenience of an all-in-one product is that it won’t be as potent. Since glycolic acid and niacinamide don’t play well together, a combination formula will not contain the high concentrations that you can get when using them individually, nor will it be at the optimal pH.

If this is a compromise that you’re willing to make, try one of the following:

COSRX AHA 7 Whitehead Power Liquid: This gel-like liquid contains 7% glycolic acid and 2% niacinamide, with a pH between 4.0 and 5.0.
Versed Weekend Glow Daily Brightening Solution: This gentle toner contains 3% glycolic acid and 2% lactic acid. Based on the order of the ingredients list, we can deduce that the concentration of niacinamide is 0.5-2%. It has a pH of 5.0-6.0.
Moon Juice Acid Potion Resurfacing Exfoliator: This is a liquid exfoliant with a 25% acid complex, which primarily consists of glycolic acid. Niacinamide is the fifth ingredient.

✓ Apply Them at Different Times of Day

If you’ve decided that two separate products are the way to go, the easiest way to use them is at different times of day. What you use when is totally up to you, but my recommendation is to apply your niacinamide in the morning and your glycolic acid at night.

First of all, this will save time if your mornings are rushed. Since niacinamide is non-acidic, you can put it under products with a similar pH—like your hydrating serum, moisturizer and/or sunscreen—without having to wait in between layers.

Glycolic acid, on the other hand, needs to be separated from higher-pH products by about 30 minutes, to give it time to work at its acidic pH. Most of us have more time to incorporate this waiting period when we’re doing our nighttime skincare routines.

Another reason to use your glycolic acid at night is because it can make your skin more sun-sensitive.²⁵ If you do apply glycolic acid in the morning, make sure to also wear a high-protection sunscreen.

✓ Apply Them on Alternate Mornings or Nights

Another option is to apply your glycolic acid and niacinamide on alternate mornings or nights. So, one evening you could apply your glycolic acid after cleansing, and the next evening, you’d use your niacinamide instead. Or, this could happen in the mornings, if that’s your preference.

Again, the one caveat here is that you need to be mindful of pH levels if you plan to layer other skincare products on top of the acid. My general rule is that any products that are more than about 1.0-2.0 apart need to be separated by a 30-minute waiting period.

✓ Apply Them 30 Minutes Apart

For those of us with complicated routines, who like using all the skincare, there’s one more way you can use these two ingredients. You can actually layer your glycolic acid and niacinamide together, at the same time of day—just 30 minutes apart.

When layering products, start with the one that has the lowest pH first. This will be your glycolic acid, which you’ll apply straight after cleansing. Leave it on your skin to do its thing for a good 30 minutes.

This time period will give it a chance to perform its functions, and then allows your skin’s pH to return from an acidic state back to normal (about pH 5.5). When the time is up, you can apply your niacinamide without having to worry about changing its pH and triggering redness. Finish with your hydrators and sunscreen.

You can do this as once or twice a day, depending on the strength of your glycolic acid and how well your skin tolerates it. However, most people find glycolic acid is too irritating to use on a daily basis, so consider using it every other day or every two days instead.

The Best Glycolic Acid and Niacinamide Products

As a beauty editor, I’ve tested and evaluated glycolic acid and niacinamide products from a range of brands. These are my top picks for every preference:

The Inkey List Glycolic Acid Toner

The Inkey List Glycolic Acid Toner features 10% of the active ingredient, along with 5% witch hazel water to help with oil control. It has a pH of 3.6-4.0.

Allies of Skin Prebiotics & Niacinamide Pore Refining Booster

Allies of Skin Prebiotics & Niacinamide Pore Refining Booster is a gel-serum with 10% niacinamide plus prebiotics, probiotics, Centella Asiatica and hyaluronic acid.

The Ordinary Glycolic Acid 7% Exfoliating Toner

The Ordinary Glycolic Acid 7% Exfoliating Toner combines 7% of the active ingredient with an array of soothing botanicals. Its pH is approximately 3.6.

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