October 2022 in “Linköping University medical dissertations” The method shows hair testosterone levels reflect those in saliva, but are affected by various factors and may indicate a risk for heart attack.
September 2023 in “Scientific reports” Segmental hair analysis can track testosterone over time but needs adjustments for sex, hair color, and washing frequency.
July 2022 in “Research Square (Research Square)” Hair analysis can somewhat track past testosterone levels but is influenced by factors like hair washing, growth rate, sex, and hair color.
July 2024 in “Dermatology and Therapy” Darker hair colors may increase the risk of alopecia areata, while lighter hair colors may decrease it.
November 2025 in “Zenodo (CERN European Organization for Nuclear Research)” Polyherbal hair dye creams are safer, effective, eco-friendly, and economical alternatives to synthetic dyes.