1. Compared with skin, lips are very sensitive;Ikeda T;Fragrance J,1992
2. The function of stratum corneum on lip is more “active” than on face;Arai S;J Jpn Cosmet Sci Soc,1990
3. Condition of stratum corneum in “dry and chapping lips”;Arai S;J Jpn Cosmet Sci Soc,1989
4. Functional properties of the surface of the vermilion border of the lips are distinct from those of the facial skin
5. Changes in the surface configurations of lip corneocytes and activities of desquamation‐regulating proteinases associated with lip chapping;Hikima R;IFSCC Mag,2004