5 citations
,
November 2003 in “PubMed” Chemical treatments and light exposure damage hair proteins.
7 citations
,
January 2001 in “Comprehensive series in photosciences” UV radiation significantly damages hair, especially with humidity, making it more vulnerable to further damage.
29 citations
,
August 2005 in “Biopolymers” L-cysteine slows down the breaking of bonds in hair due to electrostatic interactions.
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.
5 citations
,
April 2005 in “Journal of applied polymer science” PEI diffuses into hair at a constant rate, and urea speeds up this process.