October 2025 in “Dermatology and Therapy” This study observed that adults with thinning hair who ingested a patented botanical-based supplement experienced significant increases in hair shaft diameter and reductions in hair breakage over 180 days, suggesting improved hair strength and length across various demographic groups.
August 2007 in “Microscopy and Microanalysis” Hair fibers break by cuticle cell slipping, shape changing, cuticle fraying, and surface cracking when stretched under specific conditions.
7 citations
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September 2020 in “International Journal of Cosmetic Science” This study investigated the effects of wool-derived hydrolysed keratin peptides on relaxed textured hair and found that mid- and high-molecular weight peptides improved mechanical strength and reduced breakage in different humidity conditions.
2 citations
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September 2008 in “International Journal of Cosmetic Science” This study found that brushing hair increases the ratio of long-to-short segment breaks compared to combing, with factors like bleaching and wet combing contributing to more long segment breaks.
September 2025 in “International Journal of Cosmetic Science” This study found that for straight hair, friction mainly influences fragment formation during combing, suggesting no direct connection to tensile fatigue failure, while with textured hair, combing performance may be more complex.