research Permanent hair dyes and bladder cancer risk 24 citations , January 2001 in “International Journal of Cancer” Permanent hair dye use may increase bladder cancer risk, especially in female smokers with certain genetic traits.
research The cutaneous serotoninergic/melatoninergic system: securing a place under the sun 349 citations , January 2005 in “The FASEB journal” Human skin can make serotonin and melatonin, which help protect and maintain it.