Assay validation of hair androgens across the menstrual cycle

•Androgen concentrations are significantly associated in hair and saliva samples.•Hair androgen levels are stable within and across hair samples.•Female saliva androgens, primarily DHEA, are variable across menstrual cycle.•Hair assay can be used as a good measure for basal hormone levels.•EIA hair assay method is validated with correspondence of hair and saliva samples. Saliva is a common noninvasive biofluid for measuring stress and sex hormones, yet one pressing limitation is that salivary hormones fluctuate momentarily, daily, and (for girls) across the menstrual cycle. Hair steroid assays are thought to provide a cumulative index which collapses across hormonal variability, potentially eliminating the confound of daily and menstrual cyclicity and thereby reflecting individual differences in average hormone levels. Here we seek to validate a hair bioassay methodology and test whether hair androgens accurately measure long-term, stable androgen levels in emerging adult women across two menstrual cycles. Hair samples were collected at the end of each menstrual cycle for two cycles, and saliva samples were collected in the morning once per week across two menstrual cycles (N = 11 women). Hair samples were segmented by 1 cm for the first 4 cm to reflect the hormone levels of the past four serial months. Hair samples were assayed using commercially-available enzyme-immuno-assays for testosterone and DHEA. Hair androgen concentrations were significantly correlated with averaged saliva hormone levels (DHEA: r = .75, p