Development and validation of hair specimen collection methods among extremely short-length Afro-textured hair

Cortisol, a biomarker of stress, is slowly deposited into the growing hair strands on the head. Meyer, Novak, Hamel, and Rosenberg (2014) established a method for hair cortisol extraction and analysis, and showed that hair cortisol can serve as an integrated measure of psychophysiological stress activity during the period of hormone incorporation into the hair. The hair sample collection methods offered, however, (ie, cutting as close to the scalp as possible with scissors) is inefficient when collecting samples among participants with Afro-textured and extremely short-length hair types. In this article, we propose an alternative method for collecting hair among this group.

Our proposed alternative method involves sampling hair from all sections of the scalp, rather than the posterior-vertex position alone. This provides more volume of hair making it feasible to extract and analyze cortisol in extremely short-length Afro-textured hair types. To validate this method, we compared a homogeneous specimen of hair cortisol sampled from all regions to that from the posterior-vertex region of the scalp, a region most commonly sampled.

There was no statistical difference between the homogeneous mixture and the posterior-vertex region of the scalp.

Our findings suggest that our proposed method may serve as a feasible alternative to the currently prevailing standard collection methodology, and underscores the importance of diversifying hair cortisol research beyond the limitations of developing collection methodologies only suited for straighter-textured hair types.