January 2008 in “Chinese Journal of Spectroscopy Laboratory” Cysteine formation on hair indicates damage, best detected at pH 4.5.
2 citations,
November 2018 in “International Journal of Cosmetic Science” Chamomile extract can protect hair from damage caused by light.
7 citations,
October 2020 in “International Journal of Cosmetic Science” Different sizes of keratin peptides can strengthen hair, with smaller ones possibly increasing volume and larger ones repairing damage.