3.4. Whitening assessment
The quantitative evaluation of whitening was done by determining the changing level of luminosity index L* after 4 weeks of daily topical application of samples. As shown in Fig. 4, skin lightness increased time-dependently after UV exposure. After topical application of hesperetin microemulsion, the hyperpigmentation was lightened when compared to the control group, particularly after 29 days of application which indicated that hesperetin had a
depigmentation effect.