37 citations
,
October 2015 in “PeerJ” Perming significantly changes hair's molecular structure, while shampoo and conditioner do not.
February 2019 in “PubMed” The research found that twisting hair fibers can show changes in stiffness and damage, and help tell apart different hair treatments.
Human hair can almost fully recover its structure within about 1,000 minutes after being stretched.
81 citations
,
December 2007 in “Acta materialia” AFM helped show how hair changes under tension and the effects of damage and conditioner.
18 citations
,
January 2008 in “Sen'i Gakkaishi” Thioglycolic acid and L-cysteine change hair structure differently during perms, affecting hair strength and curling efficiency.
19 citations
,
January 2009 in “International review of cell and molecular biology” Hair's strength and flexibility come from its protein structure and molecular interactions.
16 citations
,
October 2003 in “Journal of applied polymer science” 2-iminothiorane hydrochloride improves hair waving permanence without damage.
12 citations
,
January 1934 in “Proceedings of the Royal Society of London Series B Containing Papers of a Biological Character” Stretched hair has a similar structure to natural silk, showing hair's elasticity involves reversible changes within its molecules.
3 citations
,
August 2008 in “PubMed” Repeated digital perming with sodium thioglycolate lotion significantly damages hair protein and structure.
28 citations
,
December 2010 in “Langmuir” Hair fibers interact through classical forces, which are influenced by treatments and products, important for hair care and other applications.
9 citations
,
April 2019 in “Journal of Structural Biology” Keratin fibers in hair twist left-handed.
2 citations
,
December 2010 in “PubMed” The new stiffness test works well for gels but not for sprays.
1 citations
,
January 2006 High temperatures and cosmetic processes can damage hair keratin, affecting its structure and strength.
1 citations
,
June 2014 in “[Thesis]. Manchester, UK: The University of Manchester; 2014.” Chemical modifications can alter hair's stability and flexibility, with hydrophobic interactions helping maintain structure in humid conditions.
10 citations
,
June 2019 in “Cosmetics” Mixed-race individuals have hair with varied shapes and more root damage.
1 citations
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January 2013 in “PubMed” Permanent wave treatment with thioglycolic acid changes hair structure by altering disulfide bonds.
December 2000 in “Kirk-Othmer Encyclopedia of Chemical Technology” Hair care products are regulated, with shampoos, conditioners, dyes, and styling products designed for cleaning, enhancing, and maintaining hair.
July 2023 in “Nature Reviews Chemistry” A new method strengthens hair without using harmful chemicals.
November 2024 in “Biophysical Chemistry” Hair structure changes immediately during perm treatment, with initial damage partially restored later.
7 citations
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January 1990 3 citations
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May 2009 in “International Journal of Cosmetic Science” Relaxer treatments damage African–American hair, with commercial products causing more harm than lab-made solutions.
July 2025 in “Journal of Cosmetic Dermatology” The model shows how heat damages hair, helping test hair care products.
Different treatments change the strength and flexibility of human hair.
49 citations
,
June 2004 in “Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences” Human hair becomes weaker and stretches more easily at higher temperatures.
16 citations
,
October 1992 in “Journal of cutaneous pathology” Bubble hair deformity may be caused by hair shaft trauma and can improve with gentle hair care.
13 citations
,
January 2001 in “Pediatric dermatology” A dark-haired Chinese girl had hair that looked banded under certain light but was normal under a microscope.
February 2026 in “Zenodo (CERN European Organization for Nuclear Research)” Use heat protection and proper techniques to prevent hair damage from styling.
4 citations
,
June 2022 in “Journal of cleaner production” New eco-friendly method strengthens and sets hair using light and causes less damage.
January 2012 in “Jounal of The Korean Society of cosmetology” Applying conditioner mid-treatment reduces hair damage during perms.
3 citations
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January 2018 in “International Journal of Cosmetic Science” Hair stiffness increased by 13.2% after caffeine treatment, validating the Stiffness-Angle Law as an effective measurement method.