The maker of Kanebo, Sensai and Curél said it conducted the study to determine if it was possible to improve the dryness and roughness of lips using different occlusive formulation samples comprised of a combination of common oil and wax.
“Lip balm is commonly used to care for lips and several studies regarding the effects of its components on improving lip roughness have been conducted. However, the contributions of the occlusivity of a coating film to lip roughness improvement remain unclear,” said the Makeup Research Laboratories of Kao Corporation.
The lips are an area of the human body that can easily become dry and rough because there are no sebaceous glands at the boundary between the oral mucosa and skin.
As a result, moisture evaporation is more likely to occur from the stratum corneum of the lips than from other skin types, causing many people to suffer from dryness and chapping.
Previously, Kao conducted another study on the lip to determine and quantify the significant changes to the shape of the lip and the surrounding area as women age.
The study determined that conditions such as dryness and chapping tend to peak around 30 years of age, while issues such as dullness, loss of fullness, and vaguely defined lip contours, increased along with ageing.
Occlusivity is key
To prove the effectiveness of its high occlusive formula, the Kao team tested it on 20 Japanese female subjects who have dry lip concerns.
For the experiment, the subjects were divided into two groups and each was given one of two lip balm samples.
Subjects were told to apply one of the two lip balm samples four times a day for four consecutive weeks. Use of other lip cosmetics was prohibited throughout the test period.
Visual, photography, 3D photography, and stratum corneum capacitance evaluations were performed at the baseline, and again after two and four weeks.
Visual evaluations were judged based on roughness score and wrinkle score.
Additionally, the researchers used images obtained with the firm’s newly acquired ANTERA 3D camera to measure the hollow index and quantitatively calculate wrinkles on the lips.
The group using the highly occlusive lip formula was observed to have an improved roughness score after two and four weeks, while chapping was ‘significantly reduced’ after four weeks.
Wrinkle score and hollow index were also significantly improved after four weeks of using the highly occlusive formula and no deep vertical wrinkles or dents were observed.
The stratum corneum capacitance was also found to have increased after two and four weeks,
“These results clearly showed that not only the appearance of the lips but also the condition of the stratum corneum were improved,” said Kao.
It concluded: “Although lip balm is generally used for lip care, improvement effects based on its occlusivity characteristics have not been previously revealed. The present results clarified that the occlusive property of coating film has great effects to improve lip roughness. In the future, Kao will apply this knowledge to the development of lip care formulations.”
The results of this study were previously published in the International Journal of Cosmetic Science.