Cortisol To Cortisone Ratio | Read Your Lab Report Smarter

This ratio reflects how much active cortisol is being converted into inactive cortisone in your body, and it can shift with sample type, timing, meds, and kidney enzyme activity.

You can see “cortisol” on lab reports and feel like you’ve got the whole story. Then a report adds “cortisone,” plus a ratio, and suddenly it’s not so simple.

The good news: the cortisol-to-cortisone relationship follows a clear logic. Your body makes cortisol to do work. It makes cortisone to dial that work down in specific tissues. The ratio is one way labs capture that handoff.

This article breaks down what the cortisol to cortisone ratio is, where it shows up (urine, saliva, blood), what tends to move it, and how to read it without jumping to conclusions from a single number.

What cortisol and cortisone are

Cortisol is a steroid hormone made by the adrenal glands. It helps regulate blood pressure, metabolism, immune signaling, and the body’s response to stressors. It also follows a daily rhythm, usually higher in the morning and lower later in the day.

Cortisone is closely related. It’s often described as the “inactive” form, since it binds the glucocorticoid receptor far less strongly than cortisol. That “inactive” label can mislead. Cortisone still matters because it acts like a storage-and-control form, letting tissues manage how much cortisol activity they allow locally.

Many tests measure cortisol alone. Some measure both cortisol and cortisone. When you have both, a ratio becomes possible. That ratio is not a universal constant. It’s a snapshot of conversion dynamics in the setting of a specific test method and body fluid.

Why the body switches between them

Your tissues use enzymes called 11β-hydroxysteroid dehydrogenases (often shortened to 11β-HSD) to interconvert cortisol and cortisone.

Two main forms matter for everyday interpretation:

• 11β-HSD2 shifts cortisol into cortisone in tissues like the kidney. This protects mineralocorticoid receptors from being activated by cortisol.
• 11β-HSD1 tends to shift cortisone back into cortisol inside certain tissues, acting like a local “cortisol regeneration” step.

That means the ratio can hint at whether conversion is trending more toward inactivation (more cortisone relative to cortisol) or more toward active cortisol presence (more cortisol relative to cortisone). It does not, by itself, prove a diagnosis.

Where the cortisol to cortisone ratio shows up

You might see the ratio reported in a few settings:

• 24-hour urine testing: Many labs report urinary free cortisol. Some also report urinary free cortisone, which makes a free cortisol/free cortisone ratio possible.
• Spot urine testing: Some panels use a single urine sample, often morning, for steroid profiling.
• Saliva testing: Some methods can measure both cortisol and cortisone. Salivary cortisone can track serum cortisol trends in certain contexts.
• Serum or plasma panels: Less common for ratio-style reporting, though both molecules can be measured with specialized assays.

Each sample type reflects a different “slice” of physiology. Urine reflects hormone output over time (especially with 24-hour collection). Saliva reflects free (unbound) hormone with fast timing sensitivity. Blood reflects circulating hormone at that moment, influenced by binding proteins and timing.

What the ratio is trying to capture

At a basic level, the ratio answers: “How much cortisol shows up relative to cortisone in this sample?” If cortisol is high relative to cortisone, the ratio rises. If cortisone is high relative to cortisol, the ratio falls.

In urine, many healthy people excrete more free cortisone than free cortisol, so the free cortisol/free cortisone ratio often sits below 1 in studies that measure both using mass spectrometry methods. A classic paper validating urinary free cortisone measurement found urinary free cortisone exceeding urinary free cortisol in healthy adults, yielding a ratio under 1 in that cohort. You can read the abstract details in this PubMed record on urinary free cortisone measurement.

Even with that general pattern, your lab’s reference interval still rules. Different assay methods, collection details, and populations can shift the numbers.

Why timing and collection details matter

Cortisol has strong time-of-day variation, and many tests are built around that fact. A single morning blood draw can’t stand in for an entire day. A late-night saliva sample can be useful for a different reason: it targets a time window when cortisol should be low in many people.

Urine testing helps smooth out short-term spikes because it aggregates output over many hours. A 24-hour urine collection is a common structure for cortisol evaluation in some clinical pathways.

If you’re running any cortisol-based testing, it helps to understand what the test is designed to measure. MedlinePlus gives a plain-language overview of cortisol testing across blood, urine, and saliva, plus common collection steps for 24-hour urine. See MedlinePlus “Cortisol Test” for that background.

Clinical contexts where ratio data can help

Clinicians may use cortisol and cortisone measurements, plus ratios of cortisol metabolites to cortisone metabolites, to assess enzyme activity patterns in specific conditions. One well-known use relates to reduced 11β-HSD2 activity, where cortisol is not inactivated to cortisone as expected in the kidney.

There’s also a practical, non-genetic angle: compounds in liquorice (licorice) can inhibit 11β-HSD2 and mimic a reduced-conversion pattern in some people, with effects on blood pressure and electrolytes in susceptible cases. A clinical review describing this mechanism is available at “Liquorice: a root cause of secondary hypertension” (PMC).

Ratio data can show up in broader endocrine workups too. For suspected Cushing’s syndrome, guidelines often use tests like urine free cortisol, late-night salivary cortisol, and dexamethasone suppression testing as initial steps. The Endocrine Society guideline summary is here: Endocrine Society guideline resource on Cushing’s diagnosis.

Even in those settings, the ratio is one piece. Pattern recognition across symptoms, exam findings, timing, and repeat testing carries more weight than a single ratio line.

What can shift the cortisol to cortisone ratio

Several drivers can move the ratio up or down. Some relate to biology. Some relate to the test itself.

Here are common categories that can shift results:

• Sample type: urine, saliva, and blood reflect different pools of hormone.
• Time of day: especially for blood and saliva, timing can dominate the number.
• Collection quality: a missed 24-hour urine segment changes totals and ratios.
• Kidney enzyme activity: 11β-HSD2 activity affects conversion patterns in renal tissue.
• Medications and steroids: some drugs alter cortisol production, metabolism, or assay readouts.
• Diet exposures: liquorice is a classic example tied to 11β-HSD2 inhibition in some cases.
• Lab method: immunoassays can face cross-reactivity; mass spectrometry tends to be more specific.

How to read a ratio without overreading it

Start with the basics on your report:

• What fluid was tested (24-hour urine, spot urine, saliva, serum)?
• What method was used (often listed as LC-MS/MS, GC-MS, immunoassay, or similar)?
• What units and reference interval did the lab print for your age/sex category?
• Was cortisol reported as “free,” “total,” or part of a metabolite panel?

Then treat the ratio as a direction signal, not a diagnosis label.

When the ratio runs higher

A higher cortisol-to-cortisone ratio means cortisol is elevated relative to cortisone in that sample. Possible reasons include reduced conversion of cortisol into cortisone in the tissues most reflected by that sample, higher cortisol production, or a method artifact that inflates cortisol or suppresses cortisone measurement.

In urine-based interpretation, higher ratios have been used in the assessment of impaired 11β-HSD2 activity, including genetic forms of apparent mineralocorticoid excess and acquired inhibition from certain exposures. Studies that quantify urinary free cortisol and urinary free cortisone, plus metabolite ratios, form the evidence base behind that concept. The PubMed record linked earlier outlines how urinary free cortisone can help assess 11β-HSD2 activity in vivo.

When the ratio runs lower

A lower ratio means cortisone is elevated relative to cortisol in that sample. This can line up with stronger inactivation of cortisol to cortisone, different timing effects, or sample-specific dynamics (saliva can behave differently than urine).

It can also show up when cortisol output is lower overall. If the clinical question is low cortisol production, clinicians usually rely on test designs built for that question, not a ratio alone.

When the ratio is “normal” but symptoms are not

This is common. Ratios can land in-range even when someone still has a real endocrine disorder, because:

• The disorder is intermittent.
• The sample timing missed the pattern.
• The lab method lacks specificity for the clinical question.
• Another pathway is driving the symptoms.

That’s why many endocrine pathways use repeat testing and more than one test type when suspicion remains. For cortisol excess screening, the Endocrine Society notes initial tests with high diagnostic accuracy such as urine free cortisol, late-night salivary cortisol, and dexamethasone suppression testing in appropriate settings, with follow-up based on results and clinical findings.

Ratio reporting formats you may see

Not every report prints “cortisol/cortisone.” Some reports use related urine metabolite ratios that reflect conversion across longer metabolic routes, not just free hormone levels.

Common formats include:

• Free cortisol/free cortisone (urine): a direct ratio of the free forms in urine.
• (THF + allo-THF)/THE (urine metabolites): a metabolite ratio often used in steroid profiling to infer conversion balance.
• Salivary cortisol/salivary cortisone: sometimes used in research and specialized clinical testing.

These ratios are related, yet not interchangeable. A report that uses metabolites is capturing a broader metabolism picture than the free-hormone ratio alone.

How to prepare for testing so results mean more

Preparation depends on the test. Still, some best practices apply across most cortisol-related testing:

• Follow timing instructions exactly. Timing errors can swamp subtle differences.
• List all meds and supplements. Some affect cortisol pathways or interfere with assays.
• For 24-hour urine, collect every void in the window and store as instructed.
• For saliva, avoid food, drink, and tooth brushing in the window your kit specifies.

MedlinePlus outlines collection details for blood, urine, and saliva cortisol testing, including the structure of a 24-hour urine sample and why multiple time points may be ordered. The same link earlier covers that.

Table 1: Common factors that change the ratio and what they tend to do

The table below gives a practical map. It’s not a diagnostic chart. It shows direction and why direction can change.

How clinicians use ratio clues in real workups

In practice, ratio data tends to matter most when the clinical question matches the biology the ratio reflects.

Suspected cortisol excess

When a clinician suspects cortisol excess (Cushing’s syndrome), the first-pass goal is to confirm whether cortisol output is consistently elevated or whether the daily rhythm is disrupted. That’s why recommended initial tests often include urine free cortisol, late-night salivary cortisol, or dexamethasone suppression testing in suitable patients.

In that setting, a cortisol-to-cortisone ratio may appear in comprehensive steroid panels, yet the core decision usually rests on validated screening tests and repeat confirmation. The Endocrine Society’s guideline resource summarizes common initial testing options for diagnosis pathways.

Suspected altered 11β-HSD2 activity

When the clinical question is altered 11β-HSD2 activity, urine ratios become more central. Some investigations quantify urinary free cortisol and urinary free cortisone, plus metabolite ratios, to infer conversion activity. The Clin Endocrinol (Oxf) study linked earlier is one reference point supporting measurement of urinary free cortisone as a marker tied to renal conversion activity.

In acquired inhibition scenarios, liquorice exposure is a classic driver described in clinical literature. The PMC review explains the mechanism and the downstream mineralocorticoid-like effects that can follow in certain cases.

Common reading mistakes that waste your time

These are the traps that send people spiraling after a lab portal alert:

• Mixing sample types: A saliva ratio and a urine ratio do not mean the same thing.
• Ignoring timing: A “low” morning number can be normal if the sample was taken late in the day, and the reverse can happen too.
• Skipping the method line: Method changes can explain mismatches across labs.
• Reading the ratio as a stand-alone verdict: Ratios point. They don’t label.
• Missing exposures: Diet items like liquorice, plus meds and steroid creams, can matter.

What you can do with your result right now

If you have a cortisol to cortisone ratio in hand, you can turn it into a cleaner next step by gathering context. Bring this set of notes to your clinician or keep it for your own tracking:

• Sample type and collection window (24-hour urine, spot urine, saliva time stamp, blood draw time).
• Sleep schedule in the prior two days if the test relies on morning or late-night timing.
• All meds, including steroid inhalers, steroid skin creams, and recent injections.
• Diet exposures that week, with liquorice products called out if relevant.
• Recent illness, heavy exercise, or major schedule disruption.

This context can be the difference between “repeat test” and “targeted follow-up test.”

Table 2: A practical checklist for getting a cleaner ratio result

Use this as a prep and review list. It helps reduce preventable noise.

Cortisol To Cortisone Ratio in your report: a clean way to sum it up

The ratio is a conversion snapshot. It reflects the balance between active cortisol and inactive cortisone in a specific sample, collected in a specific way, measured by a specific method.

If you want the ratio to work for you, treat it like a clue that needs context. Check the sample type, timing, and method first. Then match interpretation to the clinical question: cortisol output patterns, disrupted daily rhythm, or enzyme conversion signals tied to renal handling.

When a clinician is screening for cortisol excess, guideline-backed tests like urine free cortisol, late-night salivary cortisol, and dexamethasone suppression testing often form the backbone of the pathway. When the question is conversion activity, urinary cortisol and cortisone measurements and related metabolite ratios can add value, especially when exposures like liquorice are on the table.

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