A study by Korean firm LG Household and Health (LG H&H) has identified 30 genetic markers related to the susceptibility of individuals to retinol-induced irritation, specifically among Korean users.
Retinol is one of the stronger cosmetic ingredients that promote anti-ageing. However, it exhibits a range of irritation in users, such as scaling, burning and itching.
Results of this study could aid the development of anti-irritation ingredients and revise formulations in products to ensure higher user compliance.
“Through this study, we have laid the foundation for safer and more effective use of retinol.
“The goal is to develop global anti-wrinkle products that can be expanded and used safely and effectively,” said Kang Nae-gyu, the director of the research centre.
In cosmetics, retinol has been effective as a treatment for photoaging, which causes fine and coarse wrinkles, skin roughness and abnormal pigmentation.
It also increases collagen production in the skin, producing the “anti-wrinkle” effect; assists in exfoliation; acts as an antioxidant; and promotes skin regeneration.
However, retinol triggers effects such as itching or stinging, and at varying intensities, depending on the individual. This phenomenon occurs because skin types and sensitivities are different among individuals. It is tied to the genes involved in retinol skin stimulation.
Consequently, cosmetics customers would find it difficult to buy a product with optimal retinol content for their skin. This is because the root cause of retinol skin irritation has not been identified.
In this study, scientists gathered Korean genetic big data in customers with retinol-sensitive skin and those who do not have such skins.
The research successfully identified 30 genetic variants of 10 genes associated with retinol-induced irritation. Subsequently, the investigation identified materials that can alleviate retinol-induced molecular pathogenesis and developed a novel formula for cosmetic formulations.
The first clinical evaluation involved 173 Koreans, followed by a small-scale pilot and a large-scale evaluation to verify the anti-irritant efficacy of the said formula.
The 173 subjects applied retinol for three days, followed by a rest of four days a week, over three weeks. The concentration of retinol would increase every week, from 2,500 IU in the first week to 3,300 IU in the following week and 5,000 IU in the final week.
Subjects were then given questionnaires to fill out. The researchers would analyse their answers after the experiment ended to investigate the factors related to retinol-induced irritation.
According to the results, a high proportion of the subjects in the sensitive skin group reported experiencing irritation compared to the non-sensitive skin group. The former was also thrice likely to have experience of stopping cosmetic product usage due to skin irritation.
The type of irritation induced by retinol usage varies greatly among the individuals tested. However, stinging was most common, which comprised about three-fourths of the irritations. This was followed by burning, itching, and erythema.
Novel formula to mitigate the effects
The researchers developed a novel formula to mitigate the irritation based on the results. It consists of glucosamine, sucralfate, trehalose, ectoine, 4-T-butylcyclohexanol and Omega-9 fatty acids.
This formula can decrease skin redness, trans-epidermal water loss and decrease the degree of irritation in subjects, claimed the researchers.
“Our approach will improve the compliance of patients who require retinol for various purposes in the future while suggesting significant scientific clues to basic retinoid science, which remains to be elucidated,” they concluded.
The company has completed two domestic patent applications based on these novel findings.