Azelaic Acid Toner: What It Can Do for Redness and Dark Marks, and What It Cannot

Azelaic acid has earned its reputation. It fades stubborn marks, calms redness and helps with breakouts, and it does all of that while staying gentle enough for most skin types [1, 2]. So it is no surprise that it now turns up in toners. The catch is chemistry: azelaic acid dissolves poorly in water, and a toner is mostly water. That one fact shapes what an azelaic acid toner can and cannot do for you.

What azelaic acid does

Azelaic acid is a naturally occurring dicarboxylic acid. It works on pigment in an unusual way, acting mainly on overactive or abnormal pigment cells, which is why it suits marks and melasma rather than lightening normal skin [1]. It also calms inflammation and reduces acne-causing bacteria [2]. Our guide to azelaic acid for skin covers its full range of uses.

The headline results come from prescription strengths. In a 24-week double-blind trial in 155 people with melasma, 73% of those using 20% azelaic acid cream had good to excellent results, compared with 19% of those using 2% hydroquinone, and both groups used sunscreen [3]. A 16-week study of a 15% gel applied twice daily found that it reduced both acne and the dark marks it leaves behind in patients prone to post-inflammatory hyperpigmentation [4]. Our guide to post-inflammatory hyperpigmentation explains why those marks are so persistent.

Your skin needs months, not days, to fade a dark mark, and the trials that made azelaic acid famous ran for 16 to 24 weeks.

The solubility problem

Here is what most labels leave out. Plain azelaic acid barely dissolves in water at room temperature, so the 15% and 20% products used in those trials are gels and creams that hold the acid in a base designed to carry it. A thin, watery toner simply cannot hold that much, which is why a clear toner claiming a high percentage of plain azelaic acid deserves a second look. Formulators work around this in two ways:

Your skin needs months, not days, to fade a dark mark, and the trials that made azelaic acid famous ran for 16 to 24 weeks.

• Low-strength azelaic acid: a small amount kept in solution with the help of solvents such as propanediol, well below the strengths tested in trials.
• Potassium azeloyl diglycinate: a water-soluble derivative made by joining azelaic acid to glycine, sometimes listed under the trade name Azeloglicina.

The derivative has its own, smaller body of evidence. In a randomized, double-blind, placebo-controlled pilot study of 42 people with early-stage rosacea, a cream containing 5% potassium azeloyl diglycinate and hydroxypropyl chitosan, applied twice daily for four weeks, reduced measured redness and improved hydration [5]. That is encouraging for calming, but it was a leave-on cream combined with another active, and it did not study pigment.

What a toner is good for

An azelaic acid toner is a support step. A well-made one can help calm redness, even out tone gradually and keep pores clearer, and it layers easily under other products. It is not a substitute for a dedicated treatment if you have stubborn marks. For that, a leave-on azelaic acid serum or a prescription cream delivers much more of the acid with each application.

Apply the toner after cleansing on dry skin, pressing it in with your hands rather than a cotton pad, which soaks up a share of the liquid. Give it a minute to absorb before serum or moisturizer. Because a toner spreads thinly and quickly, it is also a practical way to cover the neck and chest, where uneven tone and redness often show up too.

Your skin usually gets far more azelaic acid from a 10% serum than from a toner, so treat the toner as the helper and the serum as the treatment.

Your skin usually gets far more azelaic acid from a 10% serum than from a toner, so treat the toner as the helper and the serum as the treatment.

How to read an azelaic acid toner label

• Position: azelaic acid or potassium azeloyl diglycinate should appear near the top of the list, not after the preservatives.
• Strength: a brand that states a percentage is easier to judge, so be wary of a toner that leans on the name without saying how much it contains.
• Added acids: some azelaic toners also contain exfoliating acids, which makes them stronger but less suitable for sensitive skin.
• Fragrance: skip it if your skin flushes or stings easily.

Who should use one

An azelaic acid toner suits people with uneven tone, early post-acne marks, oily or breakout-prone skin and skin that reddens easily. Azelaic acid is generally well tolerated, and its side effects are usually limited to mild, short-lived irritation [1]. Mild tingling in the first weeks is common, so patch test if your skin is sensitive. Persistent redness, burning or bumps deserve a dermatologist visit, since they can point to a condition that needs its own treatment.

Pairing azelaic acid with retinol and sunscreen

Azelaic acid and retinol make one of the most useful pairings for uneven tone. Azelaic acid calms the overactive pigment cells, while retinol speeds up cell turnover so that pigmented cells reach the surface and shed sooner. Our guide to retinol for dark spots explains that second half of the process.

1. Use the toner in the morning after cleansing, then moisturizer and sunscreen.
2. Use retinol in the evening.
3. If your skin is reactive, introduce one product at a time, two weeks apart.
4. Wear broad-spectrum sunscreen every day. In the melasma trial both groups used it, and fading only lasts if new sun exposure is not darkening the marks again [3].

Calm the color, then renew the skin

An azelaic acid toner helps quiet redness and keeps a routine for marks on track. The deeper work of renewing cells and rebuilding collagen still belongs to retinol, and how well a retinol is tolerated decides whether you keep using it long enough to see the results.

Nanoretinol was designed around that problem. Its 0.2% retinol is encapsulated in biomimetic lipid nanoparticles that the skin recognizes as its own, so it reaches target cells without damaging the epithelial barrier the way conventional formulas can. In North Biomedical’s study it was 232% more effective than conventional retinol in collagen recovery and 73% more effective in elastin recovery, and in 56 days of clinical use skin firmness rose by 61% and elasticity by 56% [6]. Clinical testing found minimal side effects, milder than those of conventional retinol, which makes it an easy evening partner for a morning azelaic acid toner.

References

1. Fitton A, Goa KL. “Azelaic acid. A review of its pharmacological properties and therapeutic efficacy in acne and hyperpigmentary skin disorders.” Drugs. 1991;41(5):780-798. doi:10.2165/00003495-199141050-00007
2. Searle T, Ali FR, Al-Niaimi F. “The versatility of azelaic acid in dermatology.” Journal of Dermatological Treatment. 2022;33(2):722-732. doi:10.1080/09546634.2020.1800579
3. Verallo-Rowell VM, Verallo V, Graupe K, Lopez-Villafuerte L, Garcia-Lopez M. “Double-blind comparison of azelaic acid and hydroquinone in the treatment of melasma.” Acta Dermato-Venereologica Supplementum. 1989;143:58-61. PubMed:2528260
4. Kircik LH. “Efficacy and safety of azelaic acid (AzA) gel 15% in the treatment of post-inflammatory hyperpigmentation and acne: a 16-week, baseline-controlled study.” Journal of Drugs in Dermatology. 2011;10(6):586-590. PubMed:21637899
5. Berardesca E, Iorizzo M, Abril E, et al. “Clinical and instrumental assessment of the effects of a new product based on hydroxypropyl chitosan and potassium azeloyl diglycinate in the management of rosacea.” Journal of Cosmetic Dermatology. 2012;11(1):37-41. doi:10.1111/j.1473-2165.2011.00598.x
6. North Biomedical LLC. “Nanoretinol vs. Conventional Retinol: Efficacy in Collagen and Elastin Recovery.” Clinical Study Summary, 2024. Study summary