Sofia Quaglia argues at-home cortisol tests misunderstand the hormone

In a column for Slate, Sofia Quaglia argues that direct-to-consumer cortisol tests and wellness influencers fundamentally misunderstand the role of the hormone, mistaking a complex biological regulator for a simple daily stress meter.

Key Clinical Takeaways:
• At-home cortisol tests require saliva samples taken immediately upon waking to measure the diurnal curve, but medical experts note these levels reflect multiple physiological functions rather than momentary stress.
• Endocrinologists state that elevated cortisol is a downstream feature of severe underlying conditions—such as sleep apnea, psychiatric illness, or substance use disorders—rather than an isolated root cause.
• Registered dietetics professionals recommend focusing on consistent nutritional intake, adequate carbohydrate consumption, and balanced daily routines instead of tracking hormone metrics.

The Rise of At-Home Cortisol Testing Kits

Quaglia reports on testing a daily at-home cortisol kit sold by the company Eli, which markets the tests as its hero product. Priced at $199 for 24 tests and a three-month platform subscription, the device—named the “Hormometer”—involves filling a collection stick with saliva for 60 seconds. Users then wait 20 minutes before scanning the test with a smartphone application to view their nanogram-per-milliliter measurements against an ideal diurnal curve. While the app claims 97 percent accuracy, Quaglia notes that the exercise functions more as a digital reminder or personal coach than a reliable clinical assessment.

Endocrinologists Clarify Cortisol Biology

Medical experts interviewed in the column emphasize that cortisol acts as an active component of human metabolism, circadian rhythms, inflammation control, blood sugar regulation, and blood pressure maintenance. Rachna Relwani, an endocrinologist and assistant professor of medicine at NYU, explains that the hormone does not operate as an immediate stress indicator. A higher result does not confirm current stress, nor does a normal reading guarantee the absence of it.

Underlying Triggers Versus Isolated Hormones

Susan Seav, a clinical assistant professor in the Division of Endocrinology at Stanford, points out that influencers and direct-to-consumer testing companies examine physiological stress backward. Patients dealing with severe psychiatric illness, substance use disorders, severe sleep apnea, anorexia, or major life stressors frequently exhibit abnormally high cortisol levels. However, Seav clarifies that cortisol is not the root pathology in these cases, and clinicians treat the underlying disorder rather than prescribing cortisol-lowering medications or pursuing surgical interventions.

Dietitian Recommends Routine Changes over Diagnostic Tests

Katie Whitson, a registered dietitian at Health Loft, advises individuals concerned about their cortisol levels to examine their daily routines and nutritional habits instead of purchasing diagnostic tests. Whitson recommends ensuring adequate and regular carbohydrate consumption every few hours to support brain, central nervous system, red blood cell, and cardiac function. By prioritizing consistent breakfast habits, structured eating, and proper sleep schedules, individuals can address fatigue, brain fog, and anxiety directly without relying on app-based biometric tracking.

Disclaimer: The information provided in this article is for educational and scientific communication purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider regarding any medical condition, diagnosis, or treatment plan.