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A 2026 study evaluated an anhydrous skincare concentrate containing 10% azelaic acid and 0.1% retinal, with Azepur99® used as its azelaic acid ingredient. In 23 participants, researchers reported improvements versus the vehicle in several measured skin parameters after eight weeks; the results apply to the complete formula, not Azepur99® alone.
A 2026 study reported improvements in several measured skin parameters after participants used an anhydrous concentrate containing 10% azelaic acid and 0.1% retinal for eight weeks. The formulation used Azepur99® as its azelaic acid ingredient, but the researchers assessed the finished product, so the results cannot be attributed to Azepur99® alone.
The randomized, prospective, split-face, vehicle-controlled study involved 23 participants who completed the eight-week assessment. Researchers evaluated the formula using Antera 3D imaging, standardized photographs and participant self-assessments. The report identifies the study as a trial of a novel anhydrous concentrate intended for blemish-prone skin.
Compared with the vehicle, the complete active formulation was associated with statistically significant reported improvements: 18.1% in overall redness, 12.7% in surface irregularities, 22.3% in pore parameters and 5.6% in skin texture. The report also lists a 5.2% reduction in maximum redness intensity. These are study-specific measurements over eight weeks, not evidence of a guaranteed result for individual users.
The concentrate contained six ingredients: squalane, azelaic acid, caprylic/capric triglyceride, hydrogenated vegetable oil, Hordeum vulgare seed flour and retinal. Consumer self-assessments reported that 95% of participants felt their skin was calmer, 87% noticed an improvement in overall skin condition and 82% reported reduced oiliness. Participants also reported improvements in pimple size or severity (78%) and number of pimples (74%).
Results Apply to the Finished Formula
The findings offer a clinical evaluation of one specific 10% azelaic acid and 0.1% retinal formulation, rather than a test of azelaic acid as a standalone ingredient. That distinction matters to consumers and product developers: the formula included several other ingredients, and the reported outcomes reflect use of the whole concentrate compared with its vehicle.
The study may inform discussion of how azelaic acid can be incorporated into a minimalist anhydrous product for blemish-prone skin. But its 23-person sample and eight-week duration limit how broadly the results can be applied. The reported percentages describe this study’s measurements and self-assessments; they do not establish that all products with azelaic acid or retinal will produce the same effects.
The supplier’s role is also relevant. Azeco Cosmeceuticals supplied Azepur99®, described as cosmetic-grade azelaic acid with at least 99% purity, natural origin and micronized particle size. The report says the company did not take part in study design, execution, data analysis or publication. That disclosure helps define the supplier’s involvement, while the study still provides evidence about the full formulation rather than the ingredient in isolation.
azelaic acid 10% serum for blemish-prone skin
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How the Ingredient Was Evaluated
The study by Gaudicheau, Ahlström, Gillbro and Åkerström was published in the International Journal of Cosmetic Science in 2026. Its title describes an eight-week randomized, prospective, split-face, vehicle-controlled study of an anhydrous concentrate containing 0.1% retinal and 10% azelaic acid. A split-face design compares treatments on different sides of the face, while a vehicle control helps researchers compare the active formulation with its base.
Azelaic acid has attracted attention in skincare products aimed at concerns including blemishes, visible redness and uneven tone or texture. In this report, however, the relevant evidence is limited to the specific product and study methods. Azepur99® was the azelaic acid source in that formulation; the ingredient supplier did not conduct or analyze the research, according to the report.
The study reference is listed as: Gaudicheau C, Ahlström M, Gillbro JM, Åkerström U. “Efficacy and safety of a novel anhydrous 0.1% retinal and 10% azelaic acid concentrate for blemish-prone skin: An eight-week randomized prospective split-face, vehicle-controlled study.” International Journal of Cosmetic Science, 2026; 00:1–13. DOI: 10.1111/ics.70131.
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Limits of the Eight-Week Trial
The available report does not provide enough detail here to establish how durable the observed changes were after the eight-week study ended, or whether they would persist with longer use. It also does not show whether the same outcomes would occur in a larger or more varied participant group. With 23 completers, the findings are a limited test of this particular formula, not a broad estimate of how consumers will respond.
The reported results combine a product containing both azelaic acid and retinal with its other formulation ingredients. The study therefore does not isolate the contribution of each ingredient or establish the effect of Azepur99® on its own. Although the report names the study as evaluating efficacy and safety, the source material does not provide detailed adverse-event results or a breakdown of safety findings, so those details cannot be summarized here.
The reported consumer-assessment percentages are participants’ self-reported impressions. They sit alongside imaging and photography results but should not be treated as identical measures. The source material also does not specify all participant characteristics or provide enough information to judge how representative the sample was of people with blemish-prone skin.
anhydrous azelaic acid concentrate
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Further Evidence on Formula Performance
The next useful evidence would be replication in a larger participant group, with longer follow-up and fuller reporting of safety findings and participant characteristics. Additional studies could also test how outcomes vary by skin type and separate the effects of azelaic acid, retinal and the rest of the product base.
For now, the published report supplies an eight-week evaluation of one complete concentrate. Readers considering a product with these ingredients should check its directions and warnings; the study does not establish that every formulation or use pattern is suitable for everyone. No further study milestone or follow-up publication is specified in the source material.
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Key Questions
What did the study test?
It tested an anhydrous concentrate with 10% azelaic acid and 0.1% retinal over eight weeks, comparing the active formula with a vehicle. Twenty-three participants completed the study.
What is Azepur99®’s role in the findings?
Azepur99® was the azelaic acid ingredient used in the tested formulation. The reported outcomes concern the complete product and should not be attributed to Azepur99® alone.
What changes did researchers report?
Compared with the vehicle, the active formula was associated with reported improvements in overall redness, surface irregularities, pore parameters and skin texture, as well as a reduction in maximum redness intensity. These were study-specific results over eight weeks.
Does the study show the product will work for everyone?
No. The study had 23 completers and evaluated one particular formula over eight weeks. Its findings do not guarantee the same results for every user or for other products containing azelaic acid or retinal.
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