The pH of lye and no-lye hair relaxers, including those advertised for children, is at levels that are corrosive to the skin

Background. Hair relaxers are used by up to 70% of females of black African ancestry. Occupational safety regulations list a pH ≥10.5 as irritant and a pH ≥11.50 as corrosive to the skin. Objectives. To determine the pH of all relaxers sold on the South African market and whether it is lower in no-lye relaxers and those marketed for children. Methods. Relaxers were purchased from retailers in Cape Town, but more than half (54%) of the 39 brands tested were international. The pH was determined using a benchtop pH meter with an electrode for emulsions. Three pH readings were done over 3 consecutive days for each sample, and the average was used for data analysis. Differences between relaxers were analysed using Kruskal-Wallis, Wilcoxon ranksum (Mann-Whitney) and two-sample t-tests (p