Mitigation of retinol‐induced skin irritation by physiologic lipids: Evidence from patch testing.

Background: There is a dearth of effective treatments to counter retinol‐induced skin irritation. Objective: This study aimed to investigate the efficacy of three potential mitigants: (i) phytosteryl/octyldodecyl lauroyl glutamate (PLG), (ii) a physiologic lipid mixture (PLM) comprised of ceramide three and cholesterol, and (iii) niacinamide, in ameliorating irritation instigated by retinol. Methods: An occlusive human patch test, spanning 5 days, was undertaken on 18 Chinese participants aged between 23 and 40. It was designed as a randomized, double‐blind, and vehicle‐controlled study. Clinician erythema assessment (CEA) and instrumental evaluations were employed pre and post‐test. Subsequently, a 4‐week consumer in‐use test, randomized and double‐blind in nature, was executed to substantiate the soothing effects of PLG. Results: Data from CEA and bioengineering assessments revealed that, in comparison to the vehicle control, both 2% PLG and 5% PLM notably curbed retinol‐induced skin erythema and inflammation. Notably, PLG outperformed PLM. Conversely, 3% niacinamide did not offer relief against retinol‐induced discomfort. The subsequent consumer in‐use test affirmed that treatments with 2% PLG were better tolerated than those with the vehicle alone. Conclusion: To the best of our knowledge, this study represents the first confirmation that physiologic lipids effectively mitigate retinol‐induced irritation. Given their capacity to counter retinol‐induced irritation, physiologic lipids, particularly PLG, are recommended for incorporation in retinol regimens. Additionally, the Visia‐CR a* value can serve as a robust objective measure for interpreting patch test outcomes. [ABSTRACT FROM AUTHOR]