34 citations
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September 2007 in “Experimental Dermatology” The outer layer of Merino wool is rich in sulfur proteins, making it resistant to damage.
30 citations
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April 2009 in “Mycoses” Microsporum gypseum fungus breaks down keratin in hair by digesting it enzymatically, starting with less keratinized parts.
27 citations
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May 2019 in “Cosmetics” The hair cuticle is made of tough proteins that protect the hair, but more research is needed to fully understand its structure.
10 citations
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January 2010 in “International journal of trichology” Keratin-associated proteins are part of the developing hair fiber cuticle.
8 citations
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January 2016 in “Journal of fiber science and technology” Bleaching hair increases cysteic acid levels in a predictable way.