Hormone Lab

Fatigue, mood shifts, disrupted sleep — these signs can point to cortisol running too high or too low. Here's how to tell the difference, and what to do next.

Blood and saliva cortisol tests both measure cortisol — but they don't measure the same thing. Learn how each method works, what each one is designed to tell you, and how to choose the right test for your goals.

Cortisol isn't a fixed number—it's a rhythm that naturally fluctuates, falling gradually from morning to night. When you get an unexpected reading, it's important to consider the context around it, since factors like timing, recent stress, sleep, and collection technique all impact your results. 

Your master stress hormone controls energy, sleep, and recovery—when the rhythm breaks, everything feels harder.

Your diurnal curve is your complete daily cortisol rhythm—a powerful pattern that governs your energy, sleep, and stress response.

Your evening cortisol is an extremely strong signal of sleep quality. Under 1 ng/mL = biochemically ready for sleep. Above 2 ng/mL = fighting your biology. Fix your evening cortisol, fix your sleep.

Your morning cortisol reveals your starting point for the day. Your natural peak can occur anytime in the first hour after waking—so consistency in testing time matters more than the exact timepoint.

Your CAR is your body's daily stress test. These three measurements reveal whether your stress response system is healthy, exhausted, or overactive—giving you an early warning of burnout. Your natural peak timing may vary, but the magnitude of the increase matters most.

Persistently high cortisol throughout the day isn't just stress—it's a medical red flag. If lifestyle changes don't bring levels down, consult a doctor.

An inverted curve isn't just "bad sleep"—it's a complete reversal of your body's master clock. This requires targeted intervention, not just better habits.

A flat curve is your body's way of saying: "I've been running on empty for too long." The good news? With consistent effort, most flat curves can be restored.

Discover how cortisol rhythms shape stress, sleep, and energy, and why tracking patterns with Hormometer™ provides clearer hormone insights.