Hair coloring and bleaching can permanently break down hair protein and temporarily change its properties.
49 citations,
September 2008 in “International journal of pharmaceutics” Artificial sebum L closely mimics human sebum for drug delivery research.
21 citations,
March 2017 in “Skin research and technology” Removing external lipids from hair reduces moisture and increases strength, while removing internal lipids decreases water permeability.
4 citations,
June 2016 in “PubMed” Repeated dyeing and shampooing cause hair color loss and damage.
3 citations,
June 2019 in “Journal of cosmetic dermatology” Lower pH straighteners change hair more but weaken it.