September 2024 in “Heliyon” Repeated hair dyeing significantly damages hair.
2 citations
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July 2013 in “Fashion business” Keratin essence protects and improves damaged hair.
24 citations
,
April 2016 in “Experimental Dermatology” Chemical treatments like dyeing, perming, and bleaching damage hair by altering amino acids and lipids.
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.
September 2020 in “Benha Journal of Applied Sciences” Protein hair straighteners damage the hair more than hair dyes.