Hidden excess cortisol may be behind stubborn blood pressure and blood sugar

If your blood pressure or blood sugar stays high even though you take your medicines, there may be a reason that has nothing to do with you. A hidden excess of cortisol, a hormone your body makes, turns up more often than doctors used to think. And there is a simple test to look for it.

A new review of the research says that about 1 in 4 people with hard-to-control type 2 diabetes or resistant high blood pressure had too much cortisol. That matters because it is a cause doctors can find and treat.

How the study worked

This was an expert review, which means the authors pulled together recent studies and what is known about how cortisol affects the body. It was published Oct. 28, 2026, in the European Heart Journal. The numbers come from people with hard-to-treat conditions, not from the general public.

What they found

Cortisol is a stress hormone made by the adrenal glands, two small glands that sit on top of your kidneys. Too much of it can push blood sugar up, make your body hold on to salt, raise blood pressure and strain your blood vessels.

The severe form is called Cushing syndrome. A milder form, called mild autonomous cortisol secretion, is more common and often goes unnoticed. It is linked to about 2.5 times the risk of dying from heart disease. It also goes along with more high blood pressure, type 2 diabetes and kidney trouble.

Here is how often excess cortisol showed up in two recent studies:

That is about 1 in 4 in both groups. The review gives the exact figures as 24% and 27%.

How do doctors check for it?

The test of choice is the overnight dexamethasone suppression test. You take a small 1 mg pill of a steroid medicine at bedtime. The next morning, a blood draw shows whether your body turned its own cortisol down the way it should. It is simple and uses a standard blood test.

What happens if the test is positive?

This is the encouraging part. The review describes a potentially reversible contributor to poor control. Options include medicines that block cortisol production or its effects. When the cause is something removable, such as an adrenal tumor, surgery is the first choice. The authors also call for more clinical trials and standard testing cutoffs, so care keeps getting better.

What you can do today

If you take three or more medicines for blood pressure, or your diabetes stays high despite treatment, write one question on your phone or on paper: “Should I be tested for excess cortisol?” Bring it to your next visit. Keep taking all your medicines as prescribed in the meantime.