Glycolic Acid Cleanser
✓ Glycolic acid verified
The Ordinary Glycolic Acid 7% Exfoliating Toner
Glycolic acid: 7%
Glycolic Acid vs Niacinamide: What Each Does and the Evidence
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Glycolic acid and niacinamide are two of the most popular active ingredients in skincare — and the question everyone asks is whether you can use them together. The short answer from the sources we read: probably yes, though no study tests the combination. These ingredients work through different documented mechanisms and target different problems, and the layering rules you will see online for them are mostly not backed by any source we could find.
Here's the documented difference: glycolic acid is an exfoliant that, per Cleveland Clinic, helps loosen the connection holding dead skin cells together, while niacinamide increased ceramide synthesis (a skin-barrier lipid) in a 2000 study and limited pigment transfer in a 2002 study. We found no source that says dermatologists routinely recommend using both, so we do not claim it.
Glycolic Acid vs Niacinamide at a Glance
| Factor | Glycolic Acid | Niacinamide |
|---|---|---|
| Type | AHA (alpha-hydroxy acid) | Water-soluble form of vitamin B3 (nicotinamide), per DermNet NZ |
| Documented action | Loosens bonds between dead skin cells (Cleveland Clinic) | Raised ceramide synthesis and lowered water loss in dry skin (Tanno 2000); DermNet NZ adds anti-inflammatory action and reduced sebum |
| Studied for | Pigmentation, collagen and clogged pores (Cleveland Clinic; Yamamoto 2006) | Fine lines, pigmented spots, red blotchiness, sebum, acne and barrier function in rosacea (DermNet NZ) |
| pH | FDA/CIR conclusion: pH 3.5 or higher; most OTC products about pH 4 (Medical News Today) | No source we read gives an optimal pH for niacinamide |
| How often | Cleveland Clinic: start once or twice a week, build to nightly if tolerated | Studies applied it daily or twice daily (Bissett 2004; DermNet NZ) |
| Sun sensitivity | The FDA says AHAs may increase it | No sun-sensitivity warning in sources we read, but DermNet NZ says nicotinamide does not work as a sunscreen |
| Sensitive skin | Cleveland Clinic advises caution with sensitive skin, dry skin, rosacea and eczema | DermNet NZ: well tolerated, often usable by people who cannot tolerate topical retinoids or fruit acids |
| Concentrations studied | FDA/CIR: 10% or less for consumer products; professional peels 20–70% (DermNet NZ) | 2% (Draelos 2006), 4% gel and 5% moisturizer in the studies DermNet NZ and Bissett describe |
What Is Glycolic Acid?
Glycolic acid is the smallest alpha-hydroxy acid (AHA) and, Cleveland Clinic says, comes from sugarcane. Cleveland Clinic says that small size lets it penetrate deeper than other AHAs.
Cleveland Clinic says it helps loosen the connection that holds dead skin cells together on the surface, and DermNet NZ says that lets dead skin peel off gently so the skin underneath has a fresher look with more even colour and texture. Cleveland Clinic also lists collagen stimulation among its effects, and a 2006 study in Japanese volunteers found collagen I and procollagen I increased in the upper dermis after daily use for 6 weeks.
The trade-off: the FDA says AHAs may increase sun sensitivity, and Medical News Today lists redness, itching, swelling and burning as possible reactions. Cleveland Clinic advises starting once or twice a week and working up to nightly only if your skin tolerates it. For more on choosing the right strength, see our glycolic acid percentage guide.
Important: Glycolic acid may increase your skin's sensitivity to the sun. The FDA advises sun protection while using AHAs, and Cleveland Clinic advises broad-spectrum sunscreen of SPF 30 or higher, reapplied every two hours.
What Is Niacinamide?
Niacinamide (also called nicotinamide) is, DermNet NZ says, the water-soluble, active form of vitamin B3. In skincare it is used as a multi-purpose ingredient rather than an exfoliant: none of the sources we read describes it as one.
The sourced actions are specific. In a 2000 study from Kanebo's laboratory, nicotinamide increased ceramide biosynthesis in cultured skin cells 4.1 to 5.5-fold, and topical application increased ceramide and free fatty acid levels in the outer skin layer and decreased water loss in dry skin. In a 2002 study by Procter & Gamble researchers, niacinamide did not affect melanin production directly but inhibited the transfer of melanosomes (pigment packets) from pigment cells to skin cells by 35–68% in a cell model. DermNet NZ adds that it may improve acne through anti-inflammatory action and by reducing sebum.
The practical evidence is modest and mostly industry-linked. A 12-week split-face study of a 5% niacinamide moisturizer in 50 women aged 40–60, by Procter & Gamble researchers, found improvements in fine lines and wrinkles, hyperpigmented spots, texture and red blotchiness, and said it was well tolerated. A 2006 report on 2% niacinamide found lower sebum excretion after 2 and 4 weeks in 100 Japanese participants, while in 30 Caucasian participants over 6 weeks casual sebum levels fell but sebum excretion rate did not. A "20–30% oil reduction" figure is often quoted, but no source we read gives it.
When to Use Glycolic Acid Instead
No source we read compares the two for these concerns, so this section lists what each has evidence for and labels our own reading.
Rough, uneven texture. Cleveland Clinic lists removing dead skin cells and brightening among glycolic acid's effects. Niacinamide is not described as an exfoliant by any source we read, so for a buildup of dead skin cells glycolic acid has the more direct documented mechanism; that conclusion is our reading.
Existing hyperpigmentation. Both have evidence. Glycolic acid inhibited tyrosinase in a 2003 cell study and left less melanin in treated skin in a 6-week study; niacinamide decreased facial hyperpigmentation after 4 weeks in the 2002 study. We found no source saying glycolic acid is faster, and none for a "4–6 weeks" timeline.
Fine lines and early signs of aging. Both have evidence: collagen I and procollagen I rose with glycolic acid in the 2006 study, and niacinamide improved fine lines and wrinkles in the 12-week study. We found no source showing glycolic acid does it more effectively, because none compares them.
Clogged pores and blackheads. Cleveland Clinic lists cleaning out clogged pores and preventing blackheads among glycolic acid's effects. A 2020 Cochrane review of topical acne treatments found no direct comparison of glycolic acid with nicotinamide, so which is better for comedonal acne is our reading, not a finding. The same review's peel comparison involved a salicylic-mandelic peel, which our glycolic acid vs mandelic acid page covers.
When to Use Niacinamide Instead
The same caveat applies. Here is what is documented, with the reasoning we add labelled as ours.
Sensitive or reactive skin. DermNet NZ says nicotinamide is well tolerated and often usable by people who cannot tolerate topical retinoids or fruit acids, and that in at least two studies, nicotinamide moisturizers improved skin barrier function in rosacea patients, leading to less reaction to irritants including cleansers and cosmetics. Cleveland Clinic advises caution with glycolic acid for sensitive skin and rosacea. Niacinamide is therefore a reasonable cautious choice, though no source ranks the two directly.
Excess oil. The 2006 report found 2% niacinamide lowered sebum excretion in Japanese participants and casual sebum in Caucasian participants. We did not find a source on pore size.
Acne with inflamed pimples. DermNet NZ says a 4% nicotinamide gel was as effective as 1% clindamycin gel in 76 people with moderate acne, and attributes the benefit partly to anti-inflammatory action. The Cochrane review found low-quality evidence in its nicotinamide comparisons. We found no source stating that an exfoliant makes inflamed breakouts worse.
Barrier damage or over-exfoliation. The 2000 study found topical nicotinamide raised ceramide levels and cut water loss in dry skin, which is the evidence behind its barrier reputation. Healthline's advice for over-exfoliation is to stop exfoliating until the skin has healed, then restart about once a week; we found no study of niacinamide specifically for over-exfoliated skin.
Dark spots. Niacinamide inhibited pigment transfer and decreased hyperpigmentation in the 2002 study. The claim that it is better at preventing than treating spots is not supported: the study measured reductions in existing hyperpigmentation. For glycolic acid's own evidence by type of spot, see our dark spots guide.
Can You Use Both?
Probably, but no source we read tests the combination. We found no source that most dermatologists recommend it, or that the two must never be layered. Cleveland Clinic's list of things to avoid pairing with glycolic acid when you are first starting out (other exfoliants, retinol and vitamin C serums) does not include niacinamide.
A popular explanation says niacinamide applied on top of acid can turn into niacin and cause a flush lasting an hour or two. We found no source for that, and DermNet NZ says oral nicotinamide does not cause flushing, unlike nicotinic acid. The pH claims (glycolic acid at 3.0–4.0, niacinamide at 5.0–7.0) are also unsourced: the FDA says the CIR conclusion covers glycolic acid products at pH 3.5 or higher, and Medical News Today says most over-the-counter products are around pH 4.
Three ways to combine them, if you want to be cautious
These are our suggestions, not tested regimens.
Option 1: Different times of day. Use glycolic acid in your evening routine, as Cleveland Clinic advises for glycolic acid, and niacinamide in the morning. This keeps the routine simple and makes it easy to tell which product caused a reaction.
Option 2: Same routine. Apply glycolic acid first, then niacinamide, then moisturizer. We found no source that gives an order or a wait time, so follow each product's label.
Option 3: Alternating days. Use glycolic acid on some evenings and niacinamide on the others. This reduces total exposure to actives, which is Cleveland Clinic's rationale for starting with fewer, and suits sensitive skin or beginners.
Important: If you experience persistent redness, stinging, or peeling, cut back. Healthline's guidance for over-exfoliation is to stop exfoliating until your skin has healed, then restart about once a week.
Best Products to Get Started
If you're looking for glycolic acid products that pair with a separate niacinamide serum, these are options at different concentrations. We have not tested any of them.
Best glycolic acid toner to pair with niacinamide
The Ordinary's 7% Glycolic Acid Toning Solution sits under the 10% ceiling that the FDA reports the Cosmetic Ingredient Review panel concluded is safe for consumer products. Cleveland Clinic advises starting glycolic acid once or twice a week. Whether to follow it with a niacinamide serum the same night or the next morning is a personal choice, since no source decides it.
Best gentle glycolic acid cleanser for combination routines
✓ Glycolic acid verified
L'Oreal Paris Revitalift 3.5% Pure Glycolic Acid Brightening Cleanser
Glycolic acid: 3.5%
If a leave-on toner feels like too much alongside your niacinamide routine, a glycolic acid cleanser is a lower-commitment option. Medical News Today says leave-on formulas give the acid more time to work, so our reading is that a rinse-off formula has less contact time; we found no study measuring that. L'Oreal's cleanser lists 3.5% glycolic acid.
Best lower-strength glycolic acid option for sensitive skin
✓ Glycolic acid verified
Good Molecules Glycolic Exfoliating Toner
Glycolic acid: 3.5%
Good Molecules' toner lists 3.5% glycolic acid, half the strength of The Ordinary's 7%. If you are nervous about adding glycolic acid next to niacinamide for the first time, a lower strength is a more cautious start, which is our reading rather than a tested result.
For more glycolic acid options, see our toner roundup and cleanser roundup, where we ranked every product by skin type and concentration.
Frequently Asked Questions
What to not mix with niacinamide?
No source we read lists things to avoid mixing with niacinamide. The popular claim that niacinamide and low-pH acids clash and cause flushing is one we could not source: DermNet NZ says oral nicotinamide does not cause flushing, unlike its precursor nicotinic acid, and we found no study showing that topical niacinamide turns into niacin on skin when layered with an acid. What is sourced is advice about glycolic acid: Cleveland Clinic says that when you are first starting out you may want to avoid using it with other exfoliants, retinol and vitamin C serums, and niacinamide is not on that list. Introducing one new active at a time is Cleveland Clinic's own reason, so you can tell what causes a reaction.
What should you not mix glycolic acid with?
No source we read says never, but Cleveland Clinic advises that when you are first starting out you may want to avoid using glycolic acid with other exfoliants such as lactic and salicylic acids, retinol and vitamin C serums. The AAD says retinoids, retinol and benzoyl peroxide can make skin more sensitive or peeling, and that exfoliating while using them may worsen dryness or cause breakouts. The AAD also warns that over-exfoliating can leave skin red and irritated. Niacinamide is not on any of these lists, and DermNet NZ says nicotinamide is well tolerated and often usable by people who cannot tolerate topical retinoids or fruit acids.
Can I use glycolic acid and niacinamide together?
Probably, but no source we read tests the combination. The claims that glycolic acid works at pH 3–4 while niacinamide needs pH 5–7, and that you must wait 30 minutes for your skin's pH to normalize, are not ones we could source. What is sourced: the FDA reports the Cosmetic Ingredient Review panel's conclusion covers glycolic acid products at 10% or less with a pH of 3.5 or higher, and a study by Sara Lee researchers put natural skin surface pH at about 4.7. If you want to be cautious, our suggestions, not tested regimens, are to use them at different times of day or on alternate days and to add one at a time.
Which is better for dark spots, glycolic acid or niacinamide?
No source we read compares them. Both have evidence on their own. A 2002 study by Procter & Gamble researchers found niacinamide inhibited melanosome transfer by 35–68% in a cell model and decreased facial hyperpigmentation versus vehicle after 4 weeks in two facial trials. For glycolic acid, a 2003 cell study found it inhibited melanin formation by directly inhibiting tyrosinase, and a 6-week study in Japanese volunteers found less melanin in treated skin. The claims that glycolic acid works faster and that using both targets the problem from both sides are not ones we could source.
Can glycolic acid and niacinamide cause irritation?
Either can, and the popular "niacin flush" explanation is not supported: DermNet NZ says oral nicotinamide does not cause flushing unlike nicotinic acid, and we found no source for a layering-triggered flush. For glycolic acid, Medical News Today lists redness, itching, swelling and burning as possible reactions and says to wash the product off and stop if they occur. DermNet NZ notes that if twice-daily nicotinamide gel dries the skin, you can reduce it to once a day or every other day. If you notice irritation after adding either product, cutting back to alternate days is our suggestion, not a sourced rule.
Is niacinamide or glycolic acid better for acne?
We could not find a head-to-head answer. A 2020 Cochrane review of topical treatments for acne (49 trials, 3,880 participants) found that the four trials of nicotinamide compared it only with clindamycin or erythromycin and none measured participants' own rating of improvement; for glycolic acid it found one peel trial and no difference against a salicylic-mandelic peel (40 participants, low-quality evidence). DermNet NZ says nicotinamide may improve acne through anti-inflammatory action and by reducing sebum, and that a 4% gel matched 1% clindamycin gel in 76 people with moderate acne. Cleveland Clinic lists removing dead skin cells, cleaning out clogged pores and preventing blackheads and breakouts among glycolic acid's effects. The idea that one suits inflamed pimples and the other blackheads is therefore our reading, not a finding, and we found no source that many dermatologists recommend using both.
Do I need sunscreen with niacinamide?
Yes, because of the glycolic acid, and because niacinamide is not sun protection: DermNet NZ says nicotinamide does not work as a sunscreen and does not prevent sunburn. The FDA says AHAs may increase skin sensitivity to the sun and advises sun protection; its cited study of 10% glycolic acid found the effect reversed within a week of stopping. Cleveland Clinic advises broad-spectrum sunscreen of SPF 30 or higher, reapplied every two hours. We found no source reporting that niacinamide increases sun sensitivity.
Which should I try first if I'm new to active ingredients?
No source we read ranks them as a starting point. DermNet NZ says nicotinamide is well tolerated and often usable by people who cannot tolerate topical retinoids or fruit acids, and in a 12-week study of 50 women using a 5% niacinamide moisturizer (by Procter & Gamble researchers) it was well tolerated. Cleveland Clinic advises starting glycolic acid once or twice a week and working up only if your skin tolerates it, and Medical News Today suggests a low starting concentration of around 8%. Our reading is that adding one active at a time is sensible, which matches Cleveland Clinic's reasoning; a 2–3 week gap and a 3–5% starting concentration are not sourced.
Which comes first, glycolic acid or niacinamide?
No source we read gives an order, a wait time or a pH reason, and the claim that glycolic acid must go on first with a 15–30 minute wait is unsupported. What the sources do say is about each product separately: Cleveland Clinic advises glycolic acid at night, and the AAD says to apply moisturizer immediately after exfoliating. Using glycolic acid at night and niacinamide in the morning, as the question suggests, is our suggestion for avoiding the question entirely; it is not a tested routine.
What is stronger than niacinamide?
"Stronger" is not something the sources measure across these two. Their documented actions differ: niacinamide increased ceramide synthesis in a 2000 cell and skin study and inhibited melanosome transfer in the 2002 study, and none of the sources we read describes it as an exfoliant, while glycolic acid loosens the bonds between dead skin cells (Cleveland Clinic). We found no source ranking either against prescription retinoids or benzoyl peroxide. Gentleness can be an advantage: DermNet NZ says nicotinamide is well tolerated and often usable by people who cannot tolerate topical retinoids or fruit acids.
Why is my skin getting darker after using niacinamide?
We found no source reporting that niacinamide darkens skin, and the 2002 study found it decreased hyperpigmentation. If your skin looks darker, irritation from another product is a possible cause: Medical News Today says strong or irritating skin care products can cause hyperpigmentation, and Davis and Callender say post-inflammatory hyperpigmentation tends to affect darker skin more often and more severely and that treatments need caution to prevent irritation. The claim that concentrations above 10% irritate is not one we could source. Stop new products one at a time to find the cause, and see a dermatologist if the darkening persists.