It’s Known as the Stress Hormone. I Spent Weeks Tracking Mine. Everyone Is Getting a Key Thing Wrong.

Medical Examiner Stress Test I spent weeks tracking my cortisol levels with a pricey at-home test kit—and learned what people tend to misunderstand about its relationship to our health. Years/iStock/Getty Images Plus Sign up for the Slatest to get the most insightful analysis, criticism, and advice out there, delivered to your inbox daily. It’s a Sunday morning, and in the tradition of Sunday mornings, I’m luxuriating in having nowhere to go and nowhere to be. I begin to drift back to sleep, when my eyes shoot open. I’m awake! I have to take a cortisol test! Dragging myself out of bed, I open a plastic-wrapped kit that looks weirdly like a pregnancy test, pop it in my mouth (saliva, not pee, is the relevant bodily fluid in this case), and swipe to the corresponding app on my phone (there’s always an app, isn’t there?). The cortisol test I’m trying out is most accurate when done as soon as possible after waking to accurately assess the “diurnal curve”—a peak followed by a gradual drop-off—that the hormone should take throughout the day. Scrolling through the various tips and guidelines on the app that morning, I see sleep listed as one of the major factors in keeping cortisol on track. Staring back at my bed, I wish I was, in fact, still sleeping. But if I were sleeping, I, of course, wouldn’t be tracking. For the past year or so, I’ve been tuned in to incessant chatter about cortisol, the hormone most famously associated with stress. On social media, influencers and fitness experts garner millions of views and likes on videos blaming cortisol for an array of concerns from belly fat to hair loss to “moon face.” “Do you often wake up tired?” perfectly toned millennials with titles such as “wellness professional” ask me from my screen. (Yes.) “Do you often feel stressed?” (Yes.) “Do you wish you could lose weight more easily?” (I mean, sure.) “Do you have brain fog?” (I have a healthy list of emails I keep forgetting to reply to, and the number of times I find myself saying, “It’s on the tip of my tongue,” seems to be increasing daily, so, yes again?). Could out-of-whack cortisol levels be to blame for all the symptoms I assumed were the basic hallmarks of living as an adult in 2026? Why not try to find out? A few weeks ago, I ordered a daily at-home cortisol test kit sold by Eli (cortisol tests are their hero product; testosterone tests are “coming soon”), which are $199 for 24 tests and a three-month subscription to their platform. The adorably named “Hormometer” arrived shortly after. I downloaded the app and began testing twice daily as recommended. The process, guided by the app, is relatively straightforward: fill the test with saliva by sucking on it for 60 seconds, wait 20 minutes, scan the test, get results. At the end of this process, the app displays my results against a graph showing the ideal diurnal curve and tells me how many nanograms of cortisol are in a milliliter of my saliva, a measurement that is, according to Eli, 97 percent accurate. If the measurement is higher or lower than “ideal,” the app provides a short blurb about what that could mean, like I could have slept poorly or had too much caffeine. How much could this exercise really tell me about my health? It’s unclear. The thing about cortisol is that it’s more than a stress hormone. It’s an active part of metabolism, your circadian rhythm, inflammation control, blood sugar, and blood pressure. Disruptions to cortisol regulation have been linked to a host of neurodegenerative disorders, and depression. While your cortisol levels can be affected by stress, it “isn’t a stress meter that tells us if you’re stressed at that moment in time,” said Rachna Relwani, an endocrinologist and assistant professor of medicine at NYU. “A higher result doesn’t necessarily mean you’re stressed, and a normal result doesn’t mean that you’re not stressed.” Basically: Cortisol’s role in our biological mechanics is complex, and cortisol levels aren’t really something that clinicians typically think about in isolation. Yet, Relwani said that she’s had more and more patients come to her having tested their cortisol at outside clinics or with direct-to-consumer tests like the ones I’d been doing. Unless a test indicates the very rare but serious Cushing’s syndrome—identified by sustained high cortisol levels—she won’t necessarily need to do anything with the results they show her. (And even then, she’d want to do her own testing: Many of the at-home tests, she added, are not regulated with sound data to back up their conclusions.) When a patient has taken one of these tests, the main thing it tells her is that they’re concerned about their health enough to order and take a test themselves. Then, she’ll start from scratch, asking what a patient is feeling and making clinical decisions from there. “I think in general, people are looking for answers for why they don’t feel well,” Relwani said. Because cortisol is something that can be fairly easily and quantifiably measured, and research shows that high cortisol can be a feature of a slew of problems, it’s an appealing candidate. But multiple experts say influencers promoting cortisol testing are looking at the problem backward. “Patients with severe psychiatric illness, patients who have alcohol and substance use disorder, patients who have severe sleep apnea, if you test their cortisol, it will be abnormally high,” said Susan Seav, clinical assistant professor in the Division of Endocrinology at Stanford. She listed anorexia and severe stress, such as going through a divorce, as other possible triggers. But cortisol levels aren’t really the problem here—or the way that any of those issues are diagnosed. In none of those cases would she recommend surgically removing an endocrine gland or prescribing cortisol-lowering medication (as she would for Cushing’s or rare tumors, like ones that form on the adrenal glands, which can secrete cortisol). Instead, healthcare professionals would treat the underlying disorder. Katie Whitson, a registered dietician at Health Loft, said that for those who come to see her with concerns about their cortisol, instead of taking tests, she recommends tracking their daily routines. Are they eating regularly? Exercising? Do they have an established social circle? Could they meditate as the day winds down? “We all want concrete answers,” Whitson said. But instead of concerning ourselves with measuring our cortisol, she advised thinking instead of what might affect it, and making adjustments there. Tiredness, stress, weight gain, brain fog—all of those things that influencers and testing companies say can be linked to high cortisol are things you can simply address directly. No. 1, Whitson advises, is ensuring you’re consuming enough carbohydrates—and doing so every few hours. While we tend to think that carbs promote fat storage, Whitson said that when leveraged correctly, this isn’t true. We need carbs for our brain, as well as our central nervous system, to function properly, and for our red blood cells to operate, not to mention our muscles, the most important of which is our heart. “Are you making sure you’re prioritizing having breakfast in the morning? Or are you walking out the door with a coffee?” Whitson asked. If brain fog and anxiety are concerns, simply regulating nutritional intake can solve for that, no matter what your cortisol tests say. (If the problem persists? That might be a good time to go to a doctor.) Despite the experts not being jazzed about them, I did technically find some utility in my venture into at-home cortisol testing. Since using the Hormometers, I’ve flown a red eye, had caffeine late in the afternoon, and had more than the recommended daily allowance of one glass of wine in the evening, all of which have corresponded with “out of range” cortisol readings. If asked, I probably would have told you I was feeling a little tired, wired, or off-kilter, so none of those readings were all that revelatory. Still, thanks to the nudge to examine my choices, I’ve found myself pausing and questioning whether I really do want to pour myself more coffee in the afternoons, or whether I could get by with herbal tea or water instead. It’s clear tests like Eli’s Hormometers are part of a wider movement taking place today. Many people rely on biometric readers displaying sleep, heart rate, recovery, and more. Seemingly healthy people use glucose monitors, testosterone and estrogen monitors, and DEXA scans, all promoted to anyone seeking “longevity.” I log my workouts, check my daily step average, and try to gamify myself into upping my daily water intake like the best of them, but the question remains: What has knowing my cortisol levels actually done for me? It’s not really a medical test so much as a reminder, a coach, or maybe even a horoscope of sorts. The tests are offered on a subscription basis, but having expensed the first three-month package for this article (which lasted me about three weeks), I’m not going to continue to pay for them out of pocket. In truth, when I took the last test in my possession, I was glad. To reduce stress and improve my well-being, instead of reading an app, I think I’ll go back to taking the good old advice my mother gave me: Eat well, sleep more, and do the things that help me enjoy life. Health Medicine Fitness