Can Your Fingernails Reveal How Stressed You’ve Been? Maybe

We all experience stress—but what if there were a way to physically measure just how much stress your body has been under over time? Cortisol, often called the “stress hormone,” offers one way to do that. Traditionally, researchers measure long-term cortisol levels using hair samples. But now, scientists are turning their attention to something even more accessible: your fingernails.

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In our recent systematic review, we explored whether nail cortisol—that is, the amount of cortisol found in nail clippings—could be a reliable indicator of chronic stress. We reviewed 18 human studies to see how researchers have measured nail cortisol, how it compares to other methods (like saliva or hair), and what kinds of health conditions it might help us understand.

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What we found was both promising and complex. Nail cortisol has been linked to conditions like depression and acute coronary syndrome, and in some cases, it mirrors the results found in saliva and hair. It’s also been studied across different ages and developmental stages.

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However, there’s still a long way to go before we can fully trust this method. Studies vary widely in how they collect and test nail samples, and few have looked closely at important factors like age, sex, ethnicity, or nail thickness—which could all affect the results.

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In short: your nails may carry a record of your body’s stress history, but scientists still need more research to understand how to read that record accurately.

This review highlights a growing and exciting area of stress research—one that could one day make it easier to detect long-term stress through a simple nail clipping.

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Want to know more?
👉 Click below to read the full paper.