No / Background Generation and accumulation of reactive oxygen/nitrogen species in the epidermis of patients with vitiligo has been widely documented. Moreover, semiquinone radical-mediated sensitivity has been shown in blood lymphocytes of these patients. Objectives To determine the possible mechanism behind Q10-induced facial vitiligo. Methods This was a clinical assessment supported by in vivo Fourier transform–Raman spectroscopy and repigmentation. Results Topical Q10 application generated hydrogen peroxide (H2O2) leading in turn to facial vitiligo in susceptible individuals. Proof of the basic result stemmed from reduction of epidermal H2O2 by using narrowband ultraviolet B-activated propseudocatalase PC-KUS in association with cessation of depigmentation and repigmentation of the lost skin colour. Conclusions Over-the-counter availability of Q10-containing topical formulations can be harmful to individuals susceptible to vitiligo.