Earwax sampling could measure stress hormone

A novel method to sample earwax could be a cheap and effective way to measure the hormone cortisol, according to a study led by researchers at UCL and King's College London. The findings, published in the academic journal Heliyon , could point to new ways of monitoring depression and stress-linked conditions. The new device can be used at home without clinical supervision, facilitating medical check-ups while maintaining social distancing due to COVID-19, and may also have the potential to measure glucose or COVID-19 antibodies that accumulate in earwax. Lead researcher Dr Andres Herane-Vives (UCL Institute of Cognitive Neuroscience and Institute of Psychiatry, Psychology & Neuroscience, King's College London) said: "Cortisol sampling is notoriously difficult, as levels of the hormone can fluctuate, so a sample might not be an accurate reflection of a person's chronic cortisol levels. Moreover, sampling methods themselves can induce stress and influence the results. "But cortisol levels in earwax appear to be more stable, and with our new device, it's easy to take a sample and get it tested quickly, cheaply and effectively." Cortisol has been considered as a possible biomarker, or objective biological measure, for depression, but researchers have been stymied by challenges in accurately measuring cortisol levels. The most common technique is with hair samples, but they are more subject to short-term fluctuations in cortisol, and not everyone has enough hair for a reliable sample.