Background: Brazilian keratin treatment (BKT) and similar straightening products fix and retain a straight shape even when the hair is wet. Unacceptably high concentrations of formaldehyde have been reported in such products.
Objective: We sought to measure the formaldehyde concentration in all BKT brands marketed in South Africa in 2012.
Methods: We quantified formaldehyde by high-performance liquid chromatography with ultraviolet light detection after derivatization with dinitrophenylhydrazine. All components of 7 identified commercial brands were each tested 3 times.
Results: The maximum safe concentration of formaldehyde set by the US Cosmetic Ingredient Review Expert Panel is less than 0.2%. Of the 7 commercial BKT brands, 6 had formaldehyde levels that ranged from 0.96% to 1.4%, ie, 5 times higher than the recommended level; these included 5 brands labeled formaldehyde-free.
Limitations: The study is limited by not including all internationally available BKT products.
Conclusions: Formaldehyde concentrations in BKT products may exceed recommended levels and serve as a health hazard. Industry monitoring is needed to improve compliance and protection of hairdressers and consumers.
Keywords: BKT; Brazilian keratin treatment; Brazilian keratin treatments; DNPH; DNPHF; HPLC; dinitrophenylhydrazine; formaldehyde; formaldehyde dinitrophenylhydrazone; hair; hairdressing; high-performance liquid chromatography; public health.
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