JOURNAL OF COSMETIC SCIENCE 12 3. R3 = Last maximum amplitude (last maximal deformation). 4. R4 = Last minimum amplitude (last residual deformation). 5. R5 = Ur/Ue, net elasticity without viscous deformation. 6. R6 = Uv/Ue, the ratio between delayed and immediate deformation, which indicates the relative contributions of the viscoelastic plus viscous and the elastic distension to the total deformation (viscoelastic ratio, the ratio of viscoelastic to elastic distension). 7. R7 = Ur/Uf, the ratio of immediate retraction to the total deformation, which is called biological elasticity (the ratio of immediate retraction to total distension). 8. R8 = Ua, the fi nal retraction after removal of the vacuum (total recovery of the skin). 9. R9 = R3–R0, the difference in maximal skin deformation between the last and the fi rst suction called hysteresis (H). LIMITATIONS OF THE STUDY The current study has two main limitations. First, the number of volunteers who used the emulgel was relatively small. However, this experimental step allowed gathering relevant data on the effi cacy and the sensorial effects of the emulgel prepared and used in this study. Second, we did not compare the effi cacy and the sensorial effects of the emulgel with those of the gel and the emulsion components used to prepare the emul- gel separately. Table VII Results of Paired Sample T-Test Analysis Property Mean N p-value Moisturization of LG emulgel 4.0714 42 0.198 Moisturization of blank emulgel 3.8810 42 Cooling effect of LG emulgel 3.7143 42 0.0001 Cooling effect of blank emulgel 2.7381 42 Emollience of LG emulgel 4.0952 42 0.063 Emollience of blank emulgel 3.8095 42 Odor of LG emulgel 4.1905 42 0.0001 Odor of blank emulgel 1.7143 42 Smoothness of LG emulgel 4.1667 42 0.006 Smoothness of blank emulgel 3.7857 42 Absorbance of LG emulgel 4.0952 42 0.653 Absorbance of blank emulgel 4.0238 42 Compatibility of LG emulgel 4.0238 42 0.230 Compatibility of blank emulgel 3.7857 42 Astringent effect of LG emulgel 2.4286 42 0.254 Astringent effect of blank emulgel 2.1667 42 Overall evaluation of LG emulgel 3.9286 42 0.0001 Overall evaluation of blank emulgel 3.4286 42 Free sample of LG emulgel 1.1190 42 0.0001 Free sample of blank emulgel 1.4762 42 Ready-to-buy LG emulgel 1.0952 42 0.005 Ready-to-buy blank emulgel 1.3095 42

EMULGEL FORMULATION AND IN VITRO AND IN VIVO ASSESSMENT 13 CONCLUSION According to the obtained results in this study, it could be concluded that the natural emulgel, including virgin olive and LG essential oils extracted from the Holy Land, was successfully formulated based on its in vitro assessment. Besides, this product showed a Figure 5. Skin deformation curve obtained with CutoMPA 580, aperture 2 mm. Figure 6. Maximal recovery area of the skin.