Examining the acceptability of providing hair or fingernail samples as a biomarker of physiological stress among older adolescents.

Background. Cortisol derived from hair and fingernail samples can be used as a chronic stress biomarker, but feasibility depends on participant acceptability. While concerns regarding hair sampling have been previously documented, perceptions of nail sampling remain underexplored due to the relative novelty of the method.Methods. Participants were recruited via a university participant pool (N = 110, aged 17-22). Participants completed an online survey assessing initial willingness to provide hair and fingernail samples for stress biomarker research, factors discouraging participation, and willingness after watching brief informational videos.Results. Willingness to provide hair and nail samples were highly correlated; 55.5% willing to provide either, 7.3% willing for only hair, and 7.3% willing for only nails. Significant predictors of willingness to provide hair samples were concerns about hair being cut and discomfort with the idea of hair collection, while nail sampling willingness was negatively associated only with discomfort with the idea of nail collection. There was no significant change in willingness to provide either sample following the presentation of an informational video Discussion. Based on acceptability ratings, nail sampling for cortisol appears to be feasible for adolescent health research, yielding acceptability levels strongly correlated with and comparable to hair sampling. Correlates of acceptability mainly concerned discomfort with the idea of hair/nail sampling, though concerns about having their hair cut was an additional correlate of willingness for hair sampling. These correlates provide insights into the concerns that require addressing to enhance willingness to provide hair/nail samples.