A Randomized Controlled Trial Analyzing the Likeability, Usability, and In-Use Efficacy of Mineral Sunscreens Across Diverse Skin Tones

Background: Mineral sunscreens are increasingly favorable among consumers. However, mineral sunscreens typically cause a white cast that can impact consumer selection and application. Objective: This study measured the whitening effect of mineral sunscreens across diverse skin tones and evaluated its relationship with consumer perception, application behavior, and the product's efficacy in terms of ultraviolet A protection factor (UVAPF) and sun protection factor (SPF). Methods: Five mineral sunscreens with differing whiteness and one chemical sunscreen were applied at 2 mg/cm2 on the forearm. Two of the 6 sunscreens were randomly assigned for uncontrolled application on the lower legs, and the participants' preferred product of the pair was then applied to the face at his/her discretion. Imaging and Hybrid Diffuse Reflectance Spectroscopy (HDRS) of the arm and face determined UVAPF and SPF. Results: Controlled application with all mineral sunscreens led to significant whitening, which was 3 times more pronounced on darker skin tones. Uncontrolled sunscreen application showed a significant reduction in the amount applied, whitening, and sunscreen efficacy. Participants had reduced preference for more whitening sunscreens and selected sunscreens in product pairings that resulted in less whitening. Conclusion: Patients may avoid sunscreens with negative whitening aesthetics or compensate with reduced application, compromising their ability to achieve appropriate sun protection, especially in darker skin tones.