Cortisol, Explained

Cortisol has become the internet’s favorite villain. Tired? Cortisol. Belly fat? Cortisol. Can’t sleep? Cortisol again, and here’s a supplement for it.

The real picture is less dramatic and more useful. Cortisol is a hormone your adrenal glands release on a daily rhythm: it rises in the early morning to help you get going and falls toward bedtime. It also spikes during stress, which is its job. A body that makes cortisol when you’re under pressure is working as designed.

Problems start when the pressure never lets up, when sleep gets chopped into pieces, and when the rhythm flattens out. Even then, most of what gets blamed on “high cortisol” online has other, more likely causes: short sleep, late caffeine, alcohol, too little daylight and too much work.

True cortisol disorders, like Cushing’s syndrome, are uncommon and are diagnosed with specific medical tests, not symptom checklists or at-home saliva kits.

The articles in this section cover what the research says about cortisol, stress and the body, which claims are marketing, and which symptoms mean you should skip the blog and see a clinician. Every article links to its sources.