JOURNAL OF COSMETIC SCIENCE 404 6) The authors state, “A comparison of Table II and Table III indicates that product B (the no-lye relaxer) was assessed to perform better than product A (the lye relaxer) with regard to straightness, softness, shininess, and dryness.” Yet only the statistical sig- nifi cance of the researcher data for straightness was reported. Further, no comparison of the two relaxers is reported to conclude that one relaxer was better than the other. 7) Different confi dence intervals, 90% and 99%, are reported for the biochemical data, yet 95% was used for the rest of the article. We repeated the paired Student’s t-tests using manuscript data [Table VI] (1) at 95% confi dence intervals. Although cystine decreased after treatment with both relaxers, only the no-lye relaxer was statistical signifi cant (Table I). Studies document the adverse effects experienced by consumers following use of relaxers (2–4) however, few assess the biochemical and physical impact on Afro hair. Lee et al. (5), in a transmission electron microscopy (TEM) study, reported shaft damage in all three ethnicities (cuticle detachments, cell membrane complex, and hair cortex damage) seen with a single use damage increased with repeated chemical straightening. Mamabolo et al. (1) correlate the greater decrease in cystine after no-lye relaxer treatment with “increased straightness and better performance.” The decrease in cystine is a surro- gate for disulfi de bond disruption, which allows hair to be permanently straightened. However, cystine is crucial for hair strength and reduced levels are associated with fragile brittle hair that fails to grow long, similar to the hair in trichothiodystrophy, a genetic fragile-hair disease (6). Virgin African hair has identical sulfur staining (a surrogate for cystine) on TEM to “Asian and European hair” (6) however, it grows much shorter than that of other groups. Relaxed hair (which is straight compared to virgin hair) was also reported to grow much shorter than expected (7) and to have lower cystine levels in distal versus proximal hair (8). This led to the speculation that relaxers weaken hair and induce breakage (7). This hypothesis was recently confi rmed by Bryant et al. (9) who reported that, compared to virgin hair, relaxed hair had lower break stress and higher premature failure rates (more so in distal versus proximal hair. Thus, breakage in virgin hair is me- chanical from combing tight curls, whereas in relaxed hair, it is from chemical fragility. This partly explains the great length to which uncombed virgin Afro hair (dreadlocks) grows. Relaxers also cause contact dermatitis and alopecia (10–12). Table I p-Values for Pairs of Groups of Hair Samples Calculated Using Data (Cystine Levels) from Mamabolo et al.(1) Groups compared (n = 5) p-Value Mamabolo et al.(1) Original (1 used) CI Recalculated 95% CI BT vs. L 9.1[6.7–11.9] vs. 7.8 [2.5–9.9] 0.086 (p 0.1) 2.7 (0.20–5.20) [90% CI] 2.7 (−0.58 to 5.96) BT vs. N 9.1[6.7–11.9] vs. 4.0 [2.9–4.8] 0.005 (p 0.01) 5.38 (1–9.77) [99% CI] 5.38 (2.73–8.02) L vs. N 7.8[2.5–9.9] vs. 4.0 [2.9–4.8] 0.085 (p 0.1) 2.68 (0.16–5.20) [90% CI] 2.68 (−0.61 to 5.96) BT: before treatment, L: lye, N: no-lye, CI: confi dence interval for the mean difference.

NO-LYE NOT BETTER THAN LYE RELAXERS 405 Finally, the authors(1) make conclusions that are not substantiated by the data presented. If anything, the results suggest the contrary, that no-lye are more damaging to hair than lye relaxers. However, even without the methodological issues discussed in this letter, with only 5 subjects it is diffi cult to reliably answer research questions. Mamabolo and co-authors are to be commended for a relevant contribution that is the fi rst to assess both biochemical and cosmetic effects of relaxers. Collaborations between academic centers would improve study quality, infl uence policy to reduce cosmetic adverse effects, and help protect the public. REFERENCES (1) T. Mamabolo, N. M. Agyei, and B. Summers, Cosmetic and amino acid analysis of the effects of lye and no-lye relaxer treatment on adult black female South African hair, J. Cosmet. Sci., 64, 287–296 (2013). (2) D. Nair, N. Shetty, and V. Shetty, Chemical hair relaxers have adverse effects a myth or reality, Int. J. Trichology, 5, 26–28 (2013). (3) O. A. Olasode, Chemical hair relaxation and adverse outcomes among Negroid women in South West Nigeria. JPAD, 19, 203–207 (2009). (4) B. A. Etemesi, Impact of hair relaxers in women in Nakuru, Kenya. Int. J. Dermatol., 46, 23–25 (2007). (5) Y. Lee, Y. Kim, L. Pi, S. Y. Lee, H. Hong, and W. Lee, Comparison of hair shaft damage after chemical treatment in Asian, White European, and African hair, Int. J. Dermatol., 53, 1103–1110 (2014). (6) N. Khumalo, R. Dawber, and D. Ferguson, Apparent fragility of African hair is unrelated to the cysteine- rich protein distribution: A cytochemical electron microscopic study, Exp. Dermatol., 14, 311–314 (2005). (7) H. Bryant, C. Porter, and G. Yang, Curly hair: Measured differences and contributions to breakage, Int. J. Dermatol., 51, 8–11 (2012). (8) N. P. Khumalo, J. Stone, F. Gumedze, E. McGrath, M. R. Ngwanya, and D. de Berker, ‘Relaxers’ dam- age hair: Evidence from amino acid analysis. J. Am. Acad. Dermatol., 62, 402–408 (2010). (9) N. Khumalo and F. Gumedze, African hair length in a school population: A clue to disease pathogene- sis? J. Cosmet. Dermatol., 6, 144–151 (2007). (10) N. Khumalo, K. Pillay, and R. Ngwanya, Acute ‘relaxer’-associated scarring alopecia: A report of fi ve cases, Br. J. Dermatol., 156, 1394–1396 (2007). (11) A. G. Nicholson, C. C. Harland, R. H. Bull, P. S. Mortimer, and M. G. Cook, Chemically induced cosmetic alopecia, Br. J. Dermatol., 128, 537–541 (1993). (12) N. P. Khumalo, S. Jessop, F. Gumedze, and R. Ehrlich, Determinants of marginal traction alopecia in African girls and women, J. Am. Acad. Dermatol., 59, 432–438 (2008).