A new sampling method developed by researchers from University College London may be able to test your stress levels from just your earwax. The technology is cheap, easy-to-use, and rapidly tests levels of the stress hormone cortisol within the wax. The results were published in the journal Heliyon.
“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," said lead researcher Dr Andres Herane-Vives in a statement. “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.”
For the pilot study, the team tested the device on 37 participants by removing earwax once with a syringe (a standard but slightly painful procedure), and then again one month later using the syringe in one ear and the new device in the other. The new device yielded more cortisol, was rated more comfortable by the participants, and the results were less influenced by confounding variables, such as alcohol.
Cortisol is a hormone that is produced in the adrenal gland and is considered the "fight or flight" hormone. Acting as the primary stress hormone, cortisol works to increase blood glucose levels, regulate your blood pressure, and divert the body’s resources to the areas needed most under stressful conditions.
Measuring cortisol levels within the body can help with the diagnosis of a variety of conditions, from Cushing’s syndrome (overproduction of cortisol) to Addison's disease (underproduction of cortisol). However, it may also be used as a biomarker for depression and too much stress. Oversecretion of cortisol has been directly linked to depression, but to date, there are no standard and reliable methods to measure the hormone.
Current methods involve testing cortisol levels within hair samples taken from the head of a patient, but it takes time, is unreliable and the analysis of the hair is an expensive process. Furthermore, some people simply do not have enough hair on their head to sample. Instead, Dr Herane-Vives and colleagues hope the new device allows for reliable cortisol testing with minimal effort.
It can even be performed yourself – put simply, all the device requires is a swab of earwax from inside the ear. The researchers have even put a brake on it to stop it from entering too far down the ear, something that Q-tips can do.
The study was inspired by natural wax, or honeycomb, from bees, which is known to be resistant to bacterial contamination. Dr Herane-Vives thought as earwax has similar properties, it would be suitable for at-home sampling as it could still be sent to a lab without too much risk of contamination.
Alongside testing for stress, the researchers believe the device has the potential to measure glucose or Covid-19 antibodies in earwax, although their pilot study did not test for this.
The authors do outline some limitations of the new testing method. Firstly, there may be differences with the concentration of cortisol within the hair and earwax, and they express the need for future studies to delve deeper into the difference between the two and whether this is similar for other steroids. Alongside this, the cortisol levels between cohorts were measured in different labs, which may yield different results. However, this study illuminates an interesting hormone sampling technique that will act as a starting point for future research.