April 2023 in “Han'gug miyong haghoeji/Journal of the Korean society of cosmetology” Direct heat perms cause more damage to hair than softening heat perms.
Chemical treatments weaken hair's thermal stability and structure.
63 citations
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August 1996 in “Forensic Science International” Cosmetic treatments like bleaching and perming can greatly reduce opiate levels in hair, possibly leading to false-negative drug tests.
20 citations
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January 2003 in “Journal of oleo science” Chemical treatments and daily stresses damage hair, especially the cuticle layer.
18 citations
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July 2015 in “Journal of cosmetic dermatology” Straightening and coloring hair, especially with sodium hydroxide, greatly increases protein loss.