‘Relaxers’ damage hair: Evidence from amino acid analysis - 24/04/13
Abstract |
Background |
‘Relaxers’ are used by more than two thirds of African females to straighten hair, with easy grooming and increased length often cited as reasons. A recent study reported relaxed hair lengths much shorter than expected, suggesting increased fragility; the potential for scalp inflammation and scarring alopecia remains unclear.
Objective |
To investigate the biochemical effects of ‘relaxers’ on hair.
Methods |
With informed consent, included participants represented 3 groups: natural hair, asymptomatic relaxed hair, and symptomatic (brittle) relaxed hair. Biochemical analysis was performed by using a Biochrom 30 amino acid analyzer. Differences in amino acid levels were assessed using either Wilcoxon rank sum test or matched-pairs signed-rank test.
Results |
There was a decrease in cystine, citrulline, and arginine; however, an increase in glutamine was found in all relaxed compared to natural hair. Cystine levels (milligram per gram amino acid nitrogen) were similar in natural proximal and distal hair: 14 mg/g (range, 4-15 mg/g) versus 14 mg/g (range, 12-15 mg/g); P = .139. In asymptomatic relaxed hair, cystine levels were higher in less frequently relaxed samples proximal to scalp: 7.5 mg/g (5.6-12) versus 3.3 mg/g (1.3-9.2); P = .005. Cystine levels in distal asymptomatic relaxed and symptomatic relaxed hair were similar to each other and to those in the genetic hair fragility disease trichothiodystrophy.
Limitations |
It was not possible to analyze lye and no-lye ‘relaxers’ separately.
Conclusions |
‘Relaxers’ are associated with reduced cystine consistent with fragile damaged hair. A decrease in citrulline and glutamine has been associated with inflammation; prospective studies are needed to investigate whether or how ‘relaxers’ induce inflammation.
Le texte complet de cet article est disponible en PDF.Key words : African hair, amino acids, cystine, hair fragility, hair relaxers, hair straightening
Abbreviations used : TN, TTD
Plan
Funding sources: Dr Khumalo’s post at the time of the study was funded by the Discovery Foundation of South Africa. |
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Conflicts of interest: None declared. |
Vol 62 - N° 3
P. 402-408 - mars 2010 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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