Blood, saliva, or DUTCH Adrenal — not all cortisol tests are created equal. Here's what each one actually shows you, why most standard testing leaves a critical gap, and the piece of the picture that changes everything.
I've heard it more times than I can count. "My cortisol test came back normal." Meanwhile, the patient sitting across from me is exhausted, gaining weight around the middle despite doing everything right, wired at 10pm when she should be winding down, and crashing every afternoon like clockwork. Normal. Sure.
Here's what I've come to understand after eighteen years of practice: there is more than one way to measure cortisol, and depending on which test you choose — and when — you can get a genuinely useful picture of what's happening with your adrenal function, or you can get almost no useful information at all.
Most standard testing lands in the second category.
The good news is that we have better options. And once you understand what each test is actually measuring — and more importantly, what it's missing — the choice becomes pretty clear.
Three common cortisol testing options — and an honest look at what each one can and can't tell you.
Good for flagging an obvious overt problem. Not useful for understanding why you feel the way you feel.
A meaningful step up from blood testing. Shows the rhythm, but still missing the most important piece of the picture.
The three-dimensional adrenal picture. This is what I order when I need to understand what's actually happening.
Here is the number that stops most people cold when I explain it: free cortisol — the form that saliva tests measure, the form that blood testing tries to estimate — represents approximately one percent of the total cortisol your body produces.
Cortisol metabolites, which can only be detected in urine, represent approximately eighty percent.
So when we test only free cortisol, we are looking through a window into one percent of the picture. The metabolites are giving us the other eighty.
This is why the DUTCH Adrenal exists. It combines the daily free cortisol pattern you'd see on a saliva test with the metabolite data that only urine can provide. Together, those two things give you something no single test can give you on its own: a meaningful picture of both how much cortisol your body is producing and how efficiently it's clearing it.
Production and clearance. That distinction is not academic. It changes the clinical picture completely — and it changes what we do about it.
These are the kinds of cases that show exactly why I will not try to work with adrenal function using free cortisol alone.
A patient with significant, long-standing obesity. Her free cortisol on saliva testing was on the lower end — nothing alarming, maybe something to watch. A reasonable clinical conclusion would be that cortisol is not the issue here.
But when you look at her cortisol metabolites on the DUTCH, the picture shifts entirely. She's producing cortisol at levels that exceed literally 99% of the population. The reason the free cortisol appears low is that her clearance has increased to match — her body is making it and burning through it at the same rate. That is not a low cortisol problem. That is a chronic, massive cortisol production problem that free cortisol testing was completely hiding.
A patient with hypothyroidism. Her free cortisol is elevated — the natural assumption is that she's under chronic stress, producing too much cortisol, cortisol is the driver of her symptoms. We'd be headed down a path of adrenal support and stress reduction protocols.
But her metabolites are low. What's actually happening is that the cortisol is backing up — it's not clearing properly because her sluggish thyroid has slowed cortisol metabolism along with everything else. She is not producing too much cortisol. She is not clearing it. Same free cortisol reading on a saliva test. Completely opposite clinical picture. Completely different treatment approach.
Here's what I'm looking at when I order this test — and why each piece matters.
Four collection points throughout the day showing how your cortisol rises and falls. Cortisol is supposed to peak within the first hour of waking and gradually decline. When that rhythm is off — a late-night spike, a midday crash, a flat morning — it shows up here.
These are the eighty percent of the picture that free cortisol testing misses entirely. Metabolites tell us what your body is actually producing and how well it's clearing cortisol through the liver. This is how we can tell the difference between high production, slow clearance, and both at once.
DHEA is a critical adrenal marker and functions as a buffer against the damaging effects of elevated cortisol. When DHEA is low and cortisol is chronically high, the damage to your hormones, metabolism, and immune function compounds significantly. This ratio matters as much as either number on its own.
The cortisol spike that occurs in the first 30–45 minutes after waking is your brain stress-testing your adrenals. When this response is exaggerated, it can indicate anticipatory stress — your nervous system bracing for the day before it has even started. An important window into how your body is responding to psychological and perceived stress.
I order this test when a patient's symptoms point toward adrenal or cortisol involvement — and when I need more than a single number to understand what's actually going on.
A blood test gives you a number at a single point in time. A saliva test gives you the daily rhythm of your free cortisol. The DUTCH Adrenal gives you the rhythm plus the metabolites plus DHEA plus, optionally, your stress response at waking. Those are not minor additions — they are the pieces that tell you whether your cortisol picture is one of insufficient production, excessive production, poor clearance, or some combination of all three.
Without the metabolites, you are working with incomplete information. And in functional medicine, incomplete information leads to incomplete protocols — or worse, protocols aimed at the wrong problem entirely.
If you've been told your cortisol is fine and you don't believe it — or if you know something is off with your energy, your sleep, your weight, or your stress resilience and no one has been able to explain it — this is usually where we find the answer.
I'm happy to talk through whether it makes sense for where you are.