3 citations,
May 2009 in “International Journal of Cosmetic Science” Relaxer treatments damage African–American hair, with commercial products causing more harm than lab-made solutions.
January 2011 in “Yearbook of Dermatology and Dermatologic Surgery” Hair relaxers are linked to reduced cystine levels and potential hair damage.
8 citations,
October 2014 in “Journal of analytical toxicology.” Chemical hair straightening significantly reduces detectable drug levels in hair.
March 2010 in “Cosmetic Dermatology” Hair straightening methods have advanced to improve effectiveness and reduce damage, but still rely on heat and chemicals.
November 2022 in “International journal of trichology” Glyoxylic acid straighteners cause more protein loss but have similar hair strength effects as traditional alkaline straighteners.