A randomized comparative study on melasma during summer with a visible light-protected tinted sunscreen versus a standard non-tinted sunscreen

Melasma is a common hyperpigmentation skin disorder, characterized by relapse due to sun exposure. Ultraviolet (UV) radiation is the main cause of skin pigmentation, but more recently visible light has been shown to be an important contributor. Therefore, sunscreens against UVA, UVB and visible light are key in melasma prevention, but few comparative studies have been conducted. The aim of the study is to compare a sunscreen containing photoprotection against visible light (tinted product) to a non-tinted sunscreen in the prevention of melasma relapse, using instrumental and clinical assessments.

In a single-center, randomized, investigator-blinded clinical study, 42 melasma women (mean age 39.5 years old) were included during summer with type III (93%) and IV (7%) phototypes. Divided into two groups, they applied on the whole face at least twice daily either the tinted sunscreen (SPF50+, UVA index 38, visible-light protection factor 66%) or the same sunscreen but non-tinted. At 3 visits (day [D]1, T2.5 months and T5 months), melasma was assessed by colorimetric measurements using the ITA° angle (which includes the L* and b* parameters) to evaluate skin pigmentation, L parameter for lightness and ΔE calculation (which includes the L*, b* and a* values)  for the color homogeneity, in comparison with the uninvolved area. Moreover, melasma was clinically evaluated using the mMASI (modified Melasma Area and Severity Index). The tolerance evaluation of the two sunscreens and the subjective efficacy were also performed at the end of the study.

The difference between melasma ITA° and the uninvolved area ITA° (ΔITA°) was significantly better of 18.1% (p<0.05) in the tinted sunscreen group compared to the non-tinted group, confirming an improvement of skin pigmentation with the tinted sunscreen, after 5 months of use. Similarly, the ΔL between areas, and ΔE, were better than the non-tinted sunscreen of 16.3% (p<0.05) and 4.3% (p<0.05), respectively. A significant improvement was also observed in the tinted sunscreen group regarding skin pigmentation of 35.7% (p<0.001), skin lightness of 32.6% (p<0.001), and color homogeneity of 25% (p<0.001) at T5 months, when compared to baseline. Furthermore, the women who applied the tinted sunscreen had a significant decrease of the mMASI score of 12.5% (p<0.001) after 5 months, but not statistically significant when compared to the non-tinted sunscreen, and 90% of the subjects reported that their melasma had less worsened compared to previous summers. Finally, both sunscreens showed very good tolerance.