If there was an award for the hardest-working skin-care ingredient, tretinoin would undoubtedly be a frontrunner. A synthetic derivative of vitamin A, it’s long been considered the gold standard for treating everything from acne and hyperpigmentation to fine lines. But even this dermatologist-favorite ingredient can benefit from having a good sidekick. Lately, TikTokers and skin-care enthusiasts are making the case for using tretinoin with azelaic acid, a multitasking ingredient that can help address discoloration, redness—and even offset some of the irritation tretinoin can cause.

Beverly Hills-based dermatologist Jessica Wu, MD, likens the tretinoin and azelaic acid pairing to a balanced workout routine. "It's like doing cardio plus strength training," she tells Allure, noting that many of her patients can't tolerate tretinoin alone. “They both help with acne, anti-aging, and pigmentation, so the combination is really appropriate for a wide range of patients. But,” she adds, “it has to be sequenced properly so you don't cause more irritation.”

To help you reap the benefits—without overdoing it—we asked dermatologists and cosmetic chemists to explain exactly how to use tretinoin and azelaic acid together.

Available by prescription only, tretinoin is a vitamin A derivative and is the only retinoid approved for treating signs of aging, whereas retinol is its over-the-counter alternative. “Tretinoin is considered the gold standard topical treatment for acne and one of the most well-studied ingredients for improving signs of photoaging, including fine lines, uneven pigmentation, and skin texture,” says Connie Yang, MD, FAAD, a board-certified dermatologist in New York City. The ingredient works by binding to retinoic acid in the skin, thus boosting cell turnover, stimulating collagen production, and improving things like acne, fine lines, and uneven texture.

Tretinoin isn't just for mature skin; it's prescribed to patients of all ages for different reasons. Because it decreases oil production in the sebaceous glands, it's long been a go-to acne treatment and is often recommended for teenagers, according to Julie Russak, MD, a board-certified dermatologist and the founder of Russak Dermatology Clinic in New York City. Later in life, tretinoin is equally sought after for its ability to improve the appearance of wrinkles, fine lines, and discoloration by stimulating skin-cell turnover. Says Dr. Russak, “It helps our cells replenish the surface of the skin with newer, healthier cells.”

According to Dr. Yang, a common misconception is that any irritation caused by tretinoin is because the formula is too strong. “The irritation isn't because tretinoin is damaging the skin, it's because it's asking your skin to work faster than it's used to,” she explains. “Tretinoin increases the rate at which your skin cells turn over and, while that's what makes it so effective for treating acne and improving signs of aging, it can also temporarily disrupt the skin barrier.” But as the skin adapts over several weeks, Dr. Yang adds, irritation typically improves while the benefits continue to build.

Azelaic acid is a naturally occurring dicarboxylic acid that's available in both prescription and over-the-counter strengths, Dr. Yang says. (Over-the-counter azelaic acid strengths are typically 10% or lower, while prescription formulas are available in 15% and 20% strengths.) “It's a multitasking ingredient that helps treat acne, reduce inflammation, fade post-inflammatory hyperpigmentation, and improve redness, all while targeting acne-causing bacteria,” she notes.

Azelaic acid helps reduce inflammation by targeting several inflammatory pathways in the skin, while helping fade pigmentation by inhibiting the pigment-forming enzyme tyrosinase. “Inflammation in acne isn't one single event—it's a chain of signals, one step triggering the next,” says Dr. Russak. Essentially, azelaic acid interrupts that chain at multiple points. “It neutralizes unstable oxygen molecules that help set inflammation off in the first place,” she explains. “It reduces the signaling proteins that cells use to pass the inflammatory message to each other.” Meanwhile, azelaic acid reduces the activity of NF-kB, the main cellular trigger for inflammation and redness.

For those prone to blemishes, the ingredient targets cutibacterium acnes (formerly known as propionibacterium acnes), a bacterium associated with acne. “It also interferes with how cells inside the pore stick together—which is the actual mechanism behind a clog forming—so it works not only on inflamed, angry breakouts but also on blackheads and whiteheads,” says Dr. Russak. Additionally, azelaic acid reduces keratin buildup in the skin’s outermost layer, helping dead skin cells shed more easily.

Dr. Russak points out that azelaic acid's anti-inflammatory properties also make it a go-to for treating rosacea: “For rosacea-prone skin it inhibits kallikrein-5 and the cathelicidin gene, which lowers LL-37, a peptide involved in both inflammation and the vascular reactivity behind visible redness.” By targeting this pathway, azelaic acid can lessen the flushing and redness associated with rosacea.

What sets azelaic acid apart from other ingredients is its versatility. Says Dr. Yang, “The reason I love azelaic acid is that it addresses multiple common skin concerns at once: acne, discoloration, and redness, all while causing much less irritation than most other active ingredients.”

Another major advantage is its gentle nature. Unlike many acne-fighting ingredients, azelaic acid is generally well-tolerated, making it a great option for people with sensitive skin. It also stands out as one of the few topical skin-care ingredients widely considered suitable to use during pregnancy, according to Dr. Wu. By contrast, dermatologists advise against using tretinoin during pregnancy because of the potential risk of birth defects.

Though this combination has recently taken TikTok by storm, it's hardly a new skin-care duo. “While it's a new trend on social media, dermatologists have been prescribing these medications together for decades,” says Dr. Yang. The reason is simple: The two ingredients complement each other. For example, if you're treating acne, tretinoin speeds up skin-cell turnover but doesn't kill acne-causing bacteria—a gap that azelaic acid helps fill, Dr. Wu explains. Conversely, azelaic acid isn't known to stimulate collagen production, whereas tretinoin does.

The coupling is equally beneficial for concerns like hyperpigmentation, melasma, and sun damage. “Tretinoin helps normalize and speed skin-cell turnover, so pigment-containing cells are shed more efficiently over time. It can also help other topical treatments work more effectively,” explains Mona Gohara, MD, a board-certified dermatologist based in Hamden, Connecticut. “Azelaic acid more directly targets abnormal pigment production by inhibiting tyrosinase, an enzyme involved in making melanin. It also has anti-inflammatory properties, which is particularly helpful when inflammation is contributing to discoloration." An easy way to think about it is this, says Dr. Gohara: "Azelaic acid helps turn down the faucet of excess pigment production, while tretinoin helps move the pigment that is already there up and out more efficiently.” Because the ingredients address discoloration at different points in the process, they work exceptionally well together.

Meanwhile, Dr. Russak notes, the benefits extend beyond treating acne and pigmentation. Because azelaic acid has anti-inflammatory properties, it can help minimize some of the irritation associated with tretinoin.

If you want over-the-counter options, dermatologists recommend azaleic acid from Anua and La Roche Posay, and retinol from Skinbetter and Skinceuticals.

Individually, both tretinoin and azelaic acid have been studied extensively, whereas the combination has not—at least not to nearly the same extent, according to Dr. Russak. Nevertheless, while direct clinical trial evidence on the combination is limited, she says years of research on the individual ingredients, along with clinical experience and guideline support, make it a common and reasonable treatment at the disposal of dermatologists: “Both are individually endorsed in the 2024 American Academy of Dermatology guidelines; and the Delphi consensus among board-certified dermatologists goes further, recommending a topical retinoid as first-line therapy with azelaic acid added as an adjunct for patients dealing with acne-associated hyperpigmentation.” (The Delphi consensus is a structured method where a panel of skin experts answers anonymous questionnaires in multiple rounds.)

In addition to the reasons mentioned above, tretinoin and azelaic acid don’t chemically react with each other, says Krupa Koestline, a cosmetic chemist and biotech innovator. “They don't share a reactive functional group [meaning the part of a molecule that can chemically react with another ingredient] that would cause degradation or an adverse reaction between them, the way, say, benzoyl peroxide oxidizes tretinoin.” In other words, the ingredients remain stable when used together; they don't chemically break each other down or reduce the other's effectiveness.

Dr. Russak is comfortable prescribing the two ingredients together, in part because they tend to have different side effects. “Their side-effect profiles don't overlap in the same way,” she explains. With tretinoin, irritation shows up as scaling and redness, while azelaic acid manifests as a brief tingling or burning sensation right after application that’s usually gone within a few minutes.

You generally don't want to pair tretinoin with other exfoliating acids like glycolic acid, mandelic acid (which are alpha hydroxy acids, or AHAs) or salicylic acid (which is a beta-hydroxy acid, or BHA), according to cosmetic chemist Ginger King. Azelaic acid is the exception, as King doesn't consider it an exfoliating acid.

The issue is that when you use tretinoin alongside other exfoliating acids, you end up stacking acids that can all disrupt the skin barrier, says Dr. Russak, who adds that it's worth distinguishing glycolic and lactic acid from salicylic acid as they don't behave the same way. AHAs, like glycolic and lactic acid, work on the surface, exfoliating the outer layers of the skin.

Using AHAs and tretinoin at the same time "can increase dryness, peeling, redness, and irritation,” says Dr. Gohara. “While removing surface cells can theoretically influence penetration, from a practical standpoint the bigger consideration is tolerability. You want tretinoin to work effectively without unnecessarily irritating the skin.” If you want to use both, and your skin can tolerate them, dermatologists recommend using them on alternate nights.

BHAs, like salicylic acid, are oil soluble and work “especially well inside oily pores, while tretinoin normalizes cell turnover and helps prevent pores from being clogged in the first place,” says Dr. Gohara. “They can complement each other, particularly for acne-prone skin, but using both at the same time may increase irritation without necessarily giving you better results.” Again, the advice is to use them on different days or different times of the day, like a salicylic acid-based cleanser in the morning and tretinoin at night.

When it comes to azelaic acid and tretinoin, “too much of a good thing isn’t always a good thing,” says Dr. Russak. Those with sensitive skin should proceed with caution when using the two ingredients together, as the combination may be too much for their skin to tolerate. As always, it’s important to see how your skin responds to the combination before going all in. “Make sure the barrier isn’t compromised, because if it is, it will be too irritating for the skin,” she adds.

Don’t be surprised if your skin needs time to acclimate to the combination. “When used together, especially at the start of treatment, some people may experience dryness, peeling, redness, stinging, or a temporary increase in skin sensitivity,” says Dr. Yang. Because tretinoin tends to be the more irritating of the two ingredients, these reactions may be particularly noticeable as your skin adjusts to the retinoid.

If this is your first time using either ingredient, Dr. Wu recommends starting with azelaic acid before introducing tretinoin if you have sensitive skin, since it's generally much gentler. For some people, she says, it can take up to a month for the skin to adjust to azelaic acid. And while many can tolerate using it daily from the start, those with sensitive skin should begin every other day, then increase to daily use after a week if they don't experience irritation.

Alternatively, if your goal is to address comedones or clogged pores, Dr. Wu recommends starting with tretinoin first. She suggests applying it on Monday and Friday nights, initially; if you aren't experiencing irritation, add a third night, such as Wednesday, before gradually working up to nightly use. “If on a stable routine of tretinoin with no irritation after two weeks,” she says, “you could add azelaic acid. If you can't go past three nights a week, you can alternate azelaic acid in between. If you're already using tretinoin nightly, then add azelaic acid during the day.”

Once your skin has gotten used to both ingredients, Dr. Wu recommends using azelaic acid in the morning and tretinoin at night to help minimize irritation. That said, you can layer the two ingredients if your skin can tolerate it; although, because tretinoin can increase sun sensitivity, it should only be used in the evening and always apply SPF 30 or above in the morning. If you do apply both in the same nighttime routine, start with the thinner formula. “If you have azelaic acid gel, that should go on before tretinoin cream,” says Dr. Yang.

Now what about the rest of your skin-care routine when using both tretinoin and azelaic acid? Dr. Yang suggests you keep things simple: “In the morning, use a gentle cleanser, apply azelaic acid, follow with a moisturizer if needed, and finish with a broad-spectrum sunscreen,” she says. “In the evening, cleanse, let your skin dry completely, apply a pea-sized amount of tretinoin to the entire face, and follow with a moisturizer.” For those prone to irritation, this separates the two ingredients while still providing benefits from both.

When incorporating tretinoin and azelaic acid into your routine, consult with your dermatologist, who can recommend the ideal strengths for your skin. Koestline says 0.025% tretinoin is a realistic starting point when pairing it with azelaic acid. While higher strengths, such as 0.05% and 0.1%, may be more effective, they also increase the risk of irritation. “For azelaic acid, 10% is a reasonable over-the-counter starting concentration; 15 to 20% (prescription-strength, as in Finacea/Azelex) is where most of the anti-inflammatory and pigmentation data comes from,” she adds.

While tretinoin is available by prescription only, Dr. Russak recommends encapsulated retinol formulas for those who are looking for an over-the-counter alternative. She points to Skinbetter Science’s formulas as a favorite. Dr. Russak also likes SkinCeuticals' range of retinol strengths, which allow beginners to start with a lower concentration and gradually work their way up.

For over-the-counter azelaic acid, Dr. Yang suggests Anua’s Azelaic Acid 10 Hyaluron Redness Soothing Serum and, for acne specifically, La Roche Posay’s Effaclar A.Z. Acne Face Gel. The formula you choose matters too. According to Dr. Russak, cream-gel formulations are good for acne-prone skin as they absorb easily and minimize pore blockage; creams, on the other hand, are typically better suited for people with rosacea or sensitive skin, as they're generally more moisturizing. She also recommends avoiding formulas that contain alcohol, which can further irritate already sensitive skin. Serum textures tend to work well for those with normal to combination skin.

The writer before using tretinoin and azelaic acid together, and two-to-three weeks after using the ingredient combo.

Everyone’s skin is different, but according to Dr. Wu, most people see results within about two weeks of consistent use. “You should start to see some skin looking clearer because both of them are starting to slough off the top layers of dead skin; there should be less dullness by two weeks,” she says. By the one-month mark, you should start to see some improvement in clogged pores, blackheads, and acne. “By two months,” Dr. Wu continues, “you should start to see improvement in pigmentation.”

Allure beauty director, Sarah Kinonen, has firsthand experience with the pairing. Four years ago, Kinonen’s dermatologist prescribed tretinoin and azelaic acid to her after an acne consultation. “I was dealing with a couple of hormonal breakouts that would pop up every month during my period, plus redness from my rosacea,” Kinonen recalls. “So it was during that appointment that she put me on an oral drug and a handful of topicals: Altreno (tretinoin), azelaic acid 15% (Finacea), Soolantra (for rosacea), and 100mg of Spironolactone (for hormonal breakouts).”

Kinonen says further that her skin needed time to adjust to the new lineup of topical treatments. “I had instant dryness and flaking, but I soon learned to balance them out: azelaic acid (twice a day, every day) and tretinoin (every other night),” she explains. “On nights when I use the tretinoin and azelaic acid together, I first apply a dime-sized dollop of tretinoin, wait a beat for it to dry, then layer on a hydrating serum as a barrier before going in with my azelaic acid (also a dime-sized dollop). It's the sandwich technique, and it really does help prevent dryness or peeling days later.” She follows that with a moisturizer and an occlusive balm to lock in hydration.

Allure beauty director, Sarah Kinonen, before starting on tretinoin and prescription azelaic acid, and TK TIME after.

Kinonen notes, too, that the results didn’t happen overnight—it took her a few months to notice a significant difference in her skin. “I didn't have any breakouts—and I haven't had any since, if you can believe it. It's been four years!” she says, pointing out that her results weren’t solely from tretinoin and azelaic acid. “I do think my other medications (Spironolactone and Soolantra) are also a big reason I haven't had any irritations, but the tret and azelaic acid have become non-negotiable powerhouses in my routine.”

After hearing TikTokers wax poetic about the combo, I decided to try it myself. Following my dermatologist’s recommendation (and because I'd never experienced irritation while using tretinoin in the past), I opted for 0.025% tretinoin (the same strength I used a few years ago) at night, along with 15% azelaic acid in the morning. Right away, I was pleasantly surprised by my skin’s reaction: no dryness or discomfort. Although it’s been only two weeks since I added the duo to my routine, I’ve already noticed less redness, dullness, and hyperpigmentation, as well as smoother skin texture. Time will tell how my skin continues to respond to this regimen, but so far, it’s easy to see why TikTokers and dermatologists swear by the combo.