Validation of Hair Estradiol Immuno-Assays Across the Menstrual Cycle in Emerging Adults

The study aimed to validate a hair bioassay methodology for measuring long-term androgen levels in emerging adult women across two menstrual cycles. Hair and saliva samples were collected from 11 women, with hair samples segmented to reflect hormone levels over the past four months. The results showed significant correlations between hair androgen concentrations and averaged saliva hormone levels (DHEA: r = .75, p < .05; Testosterone: r = .67, p < .05). Hair hormone stability was confirmed by significant correlations between segments corresponding to the same time period. Salivary androgen stability showed more variance within individuals for DHEA and between individuals for testosterone. The findings suggest that hair samples provide a valid and reliable estimate of average steroid levels over months, capturing individual differences in long-term hormone exposure, while saliva samples reflect short-term fluctuations. The study supports the use of hair samples, particularly the first 3-4 centimeters, as a stable hormonal index for research on stable hormone levels.