January 2023 in “Fashion and textiles” This study found that hair dyed with anionic basic hair dye lost more color after shampooing compared to cationic and nonionic dyes, with alkaline shampoo increasing this effect.
November 2016 in “University of the Arts London Research Online (University of the Arts London)” This study concluded that adding polymeric conditioning actives to shampoos improved color retention in permanently dyed hair, while additional cationic dyes at certain pH levels weakly dyed the hair directly.
April 2026 in “Cosmetics” This study developed and tested a shampoo with semi-permanent dyes designed to gradually cover gray hair, reporting maintained stability and effective gray–black coloration on high-canities hair tresses through eight wash cycles.
June 2026 in “Applied and Computational Engineering” This study reviewed the principles and classifications of hair dyes, identifying significant differences between oxidative, temporary non-oxidative, and semi-permanent non-oxidative dyes in terms of duration, application methods, and potential risks, which could help improve safety and convenience in hair dye use.
November 2025 in “Zenodo (CERN European Organization for Nuclear Research)” This study examined how different hair dye processes affect hair structure at a molecular level, finding that oxidative dyes increase keratin porosity more than non-oxidative dyes, and highlighted emerging technology aimed at reducing hair damage while preserving color quality.
