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
Chloé Gaudicheau, Maria Ahlström, Johanna Maria Gillbro, Ulf ÅkerströmAbstract
Background
Blemish‐prone skin is driven by follicular hyperkeratinization, excessive sebum production, microbial dysbiosis and inflammation, often accompanied by post‐inflammatory erythema and hyperpigmentation. Retinal and azelaic acid are established topical actives with complementary mechanisms of action, yet no clinical study has evaluated their combination in a single formulation.
Objective
To evaluate the efficacy and tolerability of a minimalist anhydrous concentrate combining retinal (0.1%) and azelaic acid (10%) in improving objective and self‐perceived features of blemish‐prone skin over 8 weeks.
Methods
In a prospective randomized, vehicle‐controlled split‐face study, participants applied the active concentrate to one side of the face and a vehicle concentrate to the contralateral side, mixed with a moisturizer immediately before application. Assessments were performed at baseline and week 8 using standardized photography, Antera 3D imaging and consumer questionnaires. Statistical comparisons were performed within subjects and between treatment conditions.
Results
Twenty‐three participants completed the study (age 16–49 years; mean 28 years; Fitzpatrick skin types I–IV). After 8 weeks, the active formulation demonstrated statistically significant improvements versus baseline and vehicle. Skin texture improved by 10.9% versus baseline ( p < 0.0001) and 5.6% versus vehicle ( p = 0.0016). Skin volume (surface irregularities/pits) decreased by 24.8% versus baseline ( p < 0.0001) and 12.7% versus vehicle ( p = 0.0053). Overall redness was reduced by 13.2% versus baseline ( p = 0.0009) and 18.1% versus vehicle ( p = 0.011), while maximum redness intensity decreased by 8.8% versus baseline ( p < 0.0001) and 5.2% versus vehicle ( p = 0.029). The pore parameter showed a 22.3% improvement versus vehicle ( p = 0.015) and 15.9% versus baseline ( p = 0.051). Self‐assessments indicated improvements in overall skin condition (87%), pimple size/severity (78%), number of pimples (74%), calmer skin feel (95%) and reduced oiliness (82%). Visible improvements within 4 weeks were reported by 65% of participants. Adverse events were few, mild and transient.
Conclusion
An anhydrous six‐ingredient concentrate combining retinal 0.1% and azelaic acid 10% significantly improved texture, surface irregularities, redness and pore appearance in acne‐prone skin over 8 weeks with good tolerability. The formulation provides a stability‐optimized approach for combining two evidence‐based actives in a minimalist system.