The efficacy of a highly occlusive formulation for dry lips

OBJECTIVE: Since skin on the lips has a lower water content in the stratum corneum (SC) and a higher transepidermal water loss (TEWL) value than skin on the cheek, the lips are usually very dry and rough areas. Therefore, a lip balm approach to increase occlusivity of the lips is generally used to reduce water loss. Although there have been reports of an improvement effect on lip roughness by specific care agents, differences in the effects due to the occlusivity of a formulation without a specific care agent have not been reported. The purpose of this study was to clarify the improvement effect on dryness and roughness of the lips by a highly occlusive formulation consisting of a combination of common oil and wax, not by a specific care agent. METHODS: Twenty Japanese female subjects with normal skin (age range 20-39 years; mean 28.1) were enrolled in this study. A 4-week continuous use test was conducted using samples with low and high occlusivity. The degree of lip roughness and wrinkles was scored, the hollow index was assessed using ANTERA 3D images, and values of capacitance and TEWL were measured. RESULTS: The hollow index was significantly correlated with both the appearance roughness score and the wrinkle score. The sample with high occlusivity showed significant improvement in the appearance roughness score, wrinkle score, the hollow index and capacitance of the SC. In a comparison between the groups of samples with different occlusive properties, a significant improvement effect in rough appearance was seen in subjects using the highly occlusive formulation. CONCLUSION: The hollow index assessed by ANTERA 3D imaging allowed the objective evaluation of the improvement in appearance. In the case of continuous use of the highly occlusive formulation, an improvement of capacitance in the SC, which is most correlated with lip roughness, was obtained after 2 and 4 weeks. These results demonstrate for the first time that a highly occlusive formulation is effective in improving the roughness of the lips, and this effect is due to the difference in the occlusive property not by a specific care agent.