Elevated formaldehyde concentration in “Brazilian keratin type” hair-straightening products: A cross-sectional study

Published:December 10, 2013DOI:https://doi.org/10.1016/j.jaad.2013.10.023


      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.


      We sought to measure the formaldehyde concentration in all BKT brands marketed in South Africa in 2012.


      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.


      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.


      The study is limited by not including all internationally available BKT products.


      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.

      Key words

      Abbreviations used:

      BKT ( Brazilian keratin treatment), DNPH ( dinitrophenylhydrazine), DNPHF ( formaldehyde dinitrophenylhydrazone), HPLC ( high-performance liquid chromatography)
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