J. Cosmet. Sci., 65, 403–405 (November/December 2014) 403 No-lye not better than lye relaxers JENNIFER C. VAN WYK, KWEZIKAZI MKENTANE, FREEDOM GUMEDZE, and NONHLANHLA P. KHUMALO, Division of Dermatology, Groote Schuur Hospital, and Department of Statistical Sciences, University of Cape Town, South Africa. Accepted for publication August 17, 2014. The general perception that “no-lye relaxers are safer” is not based on valid scientifi c evidence. We are thus delighted by the contribution from Mamabolo and co-authors entitled, “Cos- metic and amino acid analysis of the effects of lye and no-lye relaxer treatment on adult black female South African hair” (1). The comparisons were based on six parameters (length, damage, straightness, softness, shine, and volume) made by fi ve subjects. One researcher assessed the same six parameters (but also added three others: split ends, dry- ness, and wash-off time). Comparisons also included amino acid analysis. The study raises various concerns, some of which may be minor omissions or typographic but others seem more fundamental: 1) It is not stated whether the hair was relaxed with both relaxers at the same time or at different times, on the same day or on different days? This is an important technicality as it can infl uence scalp irritation. 2) It is not stated whether the scoring system that was used for hair assessment was previ- ously published or specifi cally developed for the study—and if so, how it was validated. 3) How was the hair length measured? Were the 50 strands measured after removal from the scalp? How did the study participants measure their own hair? How many mea- surements were performed? Why are standard deviations not reported? 4) The table labels suggest that “means” were used for analysis instead of medians. The study utilized the non-parametric, Wilcoxon signed-rank test to determine the statis- tical signifi cance. 5) The “wash-off time” was not defi ned we inferred that it is the time that the relaxer treatment was left on before the subject complained of scalp irritation. The results indicate a 48 s difference between the lye (13.4 min) and no lye (14.2 min) relaxer. Although the difference was not statistically signifi cant (p = 0.690), the authors still used this as evidence that the no-lye relaxer caused less irritation and was safer than the lye relaxer. It is not clear how this conclusion was reached. Address all correspondence to Nonhlanhla P. Khumalo at n.khumalo@uct.ac.za.