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Lab Markers · Hormones
Cortisol Levels: Normal Range, High & Low Symptoms, and How to Lower It
A doctor's guide to reading a cortisol result, covering what's normal at each time of day, what high and low really mean, and the steps I use to bring a stressed-out system back into rhythm.
Evidence-basedReference ranges citedMedically reviewedUpdated October 19, 2026
Cortisol Reference RangesSee how cortisol is tested →
Where your result fallsSerum (blood), 6–8 a.m.
10–20 mcg/dL
Cortisol is read by the clock, not a single cutoff. See how cortisol is tested →
0102030+ mcg/dL
Possible adrenal insufficiency
< 3 mcg/dL
Seek medical evaluation. This is a red flag, not a lifestyle fix
Low-normal to low
3–10 mcg/dL
Re-test in the morning; consider pairing with ACTH and DHEA-S
Typical morning range
10–20 mcg/dL
Look at the rhythm and your symptoms; no action needed if you feel well
Elevated, usually stress-driven
> 20 mcg/dL
Address sleep, stress, blood sugar; screen for Cushing's signs if marked
How to read your result
- Use this as a starting map, not a diagnosis.
- Read your number against the time it was drawn, and bring symptoms and the daily pattern into the picture.
- Always read a result against the time it was collected and your lab's reference range.
Quick answer & key takeaways
Cortisol is your body's main stress hormone. A normal morning blood level is about 10–20 mcg/dL, falling through the day. High cortisol usually reflects chronic stress (and, rarely, Cushing syndrome); low cortisol points to adrenal insufficiency. For the common, stress-driven kind of high cortisol, sleep, smarter exercise, daily down-regulation, steady blood sugar, and adaptogens like ashwagandha can help bring it back into rhythm.
- Normal morning (6–8 a.m.): ~10–20 mcg/dL; afternoon ~3–10 mcg/dL
- High signs: belly and face weight gain, poor sleep, high BP and blood sugar, anxiety, brain fog
- Low signs: deep fatigue, low blood pressure, salt cravings, dizziness; get evaluated
- The rhythm matters as much as the number; test in the morning, or use a multi-sample panel
- Persistent or extreme results need a medical workup. This is not a DIY situation
Few lab numbers get misread as often as cortisol, because the number only means something once you know what time it was drawn.
Cortisol is the steroid hormone your adrenal glands release in response to stress, on the orders of a brain circuit called the HPA axis. It mobilizes energy, manages blood sugar and blood pressure, dampens inflammation, and sets your sleep–wake rhythm.1 In other words, cortisol is no villain; you'd die without it. For most of my patients the problem is a stress hormone stuck in the "on" position, not a disease, with a daily curve flattened by sleep debt, blood-sugar swings, and a nervous system that never quite gets the all-clear.
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The framing matters here. The vast majority of people searching how to lower cortisol don't have a tumor. They have a rhythm knocked out of place. A small minority have a genuine medical cause that needs a doctor. This page covers both how to read a cortisol result and how to fix the common, stress-driven version, while flagging clearly when a number means you need a workup, not a routine.
I care less about a single cortisol number than about its shape across the day, a strong morning and a quiet night. Lose that rhythm and you feel it everywhere.
What is cortisol?
Quick answer
Cortisol is a steroid hormone made by your adrenal glands and controlled by the HPA axis (hypothalamus → pituitary → adrenals). It mobilizes energy, regulates blood sugar and blood pressure, calms inflammation, and drives your daily sleep–wake rhythm. It's essential, and the goal is a healthy balance.
Here's the chain of command. Your hypothalamus releases CRH, which tells the pituitary to release ACTH, which tells the adrenal cortex to make cortisol, and when cortisol rises, it signals back up the line to shut the loop off.1 That feedback loop is what keeps the system balanced. Cortisol also follows a pronounced daily rhythm: it's already climbing as you wake, surges another 50–60% in the 30–45 minutes after waking (the "cortisol awakening response"), then drifts down all day to bottom out near midnight.4
1Hypothalamus
in the brain · CRH
2Pituitary
gland · ACTH
3Adrenal glands
above the kidneys · Cortisol
4CORTISOL acts on the body
energy · blood sugar · blood pressure · inflammation · sleep–wake rhythm
5Negative feedback
rising cortisol signals the brain to ease off
Three jobs explain almost everything cortisol does:
- It runs your stress response. When your brain reads a threat, cortisol (with adrenaline) floods the system, freeing glucose and sharpening focus so you can act. Brilliant for a genuine emergency; corrosive when it fires all day over traffic, deadlines, and a phone that never stops.
- It sets your daily rhythm. The morning peak is what gets you up and alert; the nighttime trough is what lets melatonin rise and sleep take hold. When the curve flattens or reverses, running high at night and dragging in the morning, you get the classic "wired but tired" pattern.
- It regulates metabolism, blood pressure, and immunity. Cortisol raises blood sugar, supports blood pressure, and tamps down inflammation in the short term.1 Chronically high, though, it does the opposite of what you want: it drives belly fat, pushes up blood sugar and pressure, and wears down the immune system.
When the system works, cortisol is one of your best allies. The trouble is chronic activation, and that's what shows up, over and over, as a disrupted curve on a test.
What a cortisol test measures, and why it's ordered
Quick answer
A cortisol test measures the hormone in your blood, saliva, or urine to check how your adrenal glands and HPA axis are working. Doctors order it to investigate signs of too much cortisol (Cushing syndrome) or too little (adrenal insufficiency); functional practitioners also use it to map a stress-disrupted daily rhythm.2
Conventionally, a cortisol test gets ordered when there's a reason to suspect the extremes, such as the central weight gain and high blood pressure of cortisol excess, or the profound fatigue and low blood pressure of cortisol deficiency.2 That's the right instinct for ruling in or out a medical condition. Where I add a second layer for everyday patients is the rhythm: a single in-range number can hide a curve that's lost its shape, which is why a multi-sample panel often tells you more than one morning draw. More on the test types and timing below.
What are normal cortisol levels?
Quick answer
For a morning blood test (6–8 a.m.), normal is about 10–20 mcg/dL, dropping to roughly 3–10 mcg/dL by late afternoon and lowest near midnight. Saliva and urine tests have their own ranges. Always read a result against the time it was collected and your lab's reference range.2
Because the numbers move so much across the day, there's no single "normal cortisol." Here's how the common tests line up:
| Test & timing | Typical normal range | SI units | What it reflects |
|---|---|---|---|
Serum (blood), 6–8 a.m. | 10–20 mcg/dL | 276–552 nmol/L | The daily peak; the anchor value most results are judged against |
Serum (blood), ~4 p.m. | 3–10 mcg/dL | 83–276 nmol/L | Should sit clearly below the morning value |
Saliva, on waking | 10.2–27.3 ng/mL | N/A | Captures the morning awakening response |
Saliva, bedtime | 2.2–4.1 ng/mL | N/A | Should be low; a high night value flags a disrupted rhythm |
24-hour urinary free cortisol | 10–55 mcg/day | 28–152 nmol/day | Total daily cortisol output; used to screen for excess |
This is where the conventional and functional views diverge, and it's worth understanding both. Standard lab ranges are built to catch disease. They flag the values high or low enough to suggest Cushing's or Addison's. They're excellent at that. What they're not designed to catch is a curve that has lost its shape, a morning that never really peaks or a night that never settles, which is exactly the pattern I see in people who feel exhausted, anxious, and unrested while their one-time blood test reads "normal."2 Neither view is wrong; they answer different questions. The lab range answers "is this a disease?" The rhythm answers "is this system handling load well?"
Standard vs. optimal cortisol: what's the difference?
People often search for an "optimal" cortisol number. The answer is that "optimal" is really a different question. A standard range asks whether you have a disease; an optimal or functional read asks whether your rhythm and reserves are healthy. Here's how the two lenses compare:
| Lens | What it looks at | What it's good for |
|---|---|---|
Standard reference range | A single value vs. the lab's cutoffs | Ruling major disease in or out (Cushing's, Addison's) |
Functional / optimal read | The shape of the daily curve and the cortisol-to-DHEA-S balance | Gauging stress load, resilience, and whether a "normal" number is masking a disrupted rhythm |
Disease-range abnormality | A value far outside the range (e.g., morning <3 mcg/dL) | A red flag that needs prompt medical evaluation, not lifestyle changes |
So when someone asks me what their "optimal" cortisol is, I show them the rhythm and the ratio. A clear morning peak, a low night, and cortisol balanced against DHEA-S is what "optimal" looks like.
A few interpretation anchors clinicians use: a morning serum cortisol below about 3 mcg/dL strongly suggests adrenal insufficiency, while a value above roughly 15–18 mcg/dL largely rules it out; results in between call for further testing such as an ACTH stimulation test.5 The point for you as a reader is that one number rarely settles anything. Timing, symptoms, and often a repeat or second test method are what make a result meaningful.
How I read a cortisol result: rhythm first, then ratio
This is the practical difference between screening for a disease and reading a system under load. A high cortisol with a high DHEA-S is an adrenal system working hard but still keeping up. A high (or even normal) cortisol with a low DHEA-S, a high cortisol-to-DHEA ratio, is the pattern I most often see in people who are exhausted, wired at night, and gaining weight around the middle despite doing “everything right.” It’s why I rarely order a cortisol level by itself; I want the rhythm and the ratio in the same picture. (More on the markers I pair it with in cortisol and the markers around it.)
A normal morning number on a flat curve with a depleted DHEA-S can hide a stressed system that hasn’t failed a test yet.
What your cortisol result means, and what to do next
Use this as a starting map, not a diagnosis. Read your number against the time it was drawn, and bring symptoms and the daily pattern into the picture.
| Your morning result | What it may mean | A reasonable next step |
|---|---|---|
10–20 mcg/dL | Typical morning range | Look at the rhythm and your symptoms; no action needed if you feel well |
Elevated, usually stress-driven | Address sleep, stress, blood sugar; screen for Cushing's signs if marked | |
3–10 mcg/dL | Low-normal to low | Re-test in the morning; consider pairing with ACTH and DHEA-S |
< 3 mcg/dL | Possible adrenal insufficiency | Seek medical evaluation. This is a red flag, not a lifestyle fix10 |
High at night (salivary) | Disrupted daily rhythm | Prioritize sleep, light timing, and stress down-regulation; consider a full-curve panel |
Flat curve across the day | HPA-axis dysregulation | A functional workup (rhythm, DHEA-S, thyroid, blood sugar) tells you more than one value |
High cortisol: symptoms & causes
Quick answer
Persistently high cortisol most often reflects chronic stress; less commonly, it signals Cushing syndrome. Tell-tale signs include weight gain around the face and midsection, a rounded face, high blood pressure and blood sugar, easy bruising, poor sleep, anxiety, and brain fog.3
The symptoms that most often track with chronically elevated cortisol:
- Weight gain concentrated in the face, abdomen, and upper back
- A rounded "moon" face, easy bruising, or purple stretch marks (with marked excess)
- High blood pressure and high blood sugar
- Muscle weakness and thinning skin
- Anxiety, irritability, or low mood
- Brain fog and trouble concentrating
- Poor sleep, the "wired but tired" pattern
- More frequent infections from a dampened immune response
By far the most common driver is chronic stress, psychological but also physiological stress like poor sleep, over-restriction, blood-sugar swings, alcohol, and chronic overtraining. The next most common is long-term steroid (glucocorticoid) medication taken for asthma, autoimmune conditions, or inflammation.3 The rarer-but-serious cause is Cushing syndrome, where a pituitary or adrenal tumor drives cortisol overproduction; the rapid central weight gain, moon face, and purple stretch marks are its hallmark, and it needs prompt evaluation by an endocrinologist.311
Low cortisol: symptoms & causes
Quick answer
Low cortisol points to adrenal insufficiency. Symptoms include deep, persistent fatigue, low blood pressure, dizziness on standing, salt cravings, low blood sugar, and weight loss; in Addison's disease, the skin can darken. This pattern needs medical evaluation and isn't something to self-treat.5
- Deep, persistent fatigue not fixed by rest
- Low blood pressure and dizziness when standing
- Salt cravings and low blood sugar
- Unintended weight loss and poor appetite
- Darkening of the skin (a specific sign of Addison's disease)
The causes split by where the problem sits. Primary adrenal insufficiency (Addison's disease) is damage to the adrenal glands themselves, most often autoimmune. Secondary insufficiency comes from the pituitary not making enough ACTH. And a common, preventable cause is stopping long-term steroid medication too abruptly, which leaves the adrenals temporarily unable to keep up.510 This is also the territory where the popular term "adrenal fatigue" gets used, and the distinction matters: that label isn't a recognized medical diagnosis. A stress-disrupted cortisol rhythm is real and worth addressing, but it's not the same as true adrenal insufficiency, which is a distinct, testable, and treatable condition. If you have the symptoms above, get tested rather than guessing.
How to lower cortisol naturally
Quick answer
For the common, stress-driven kind of high cortisol, the levers that move the needle are sleep, smarter exercise, daily nervous-system down-regulation, blood-sugar-steady eating, and a few well-studied supplements. (A persistent or markedly high result needs a medical workup, see when to see a doctor.)
This is where most searches land. None of the steps below will fix a tumor, and they shouldn't be aimed at one. What they do address is the everyday version, a system stuck on high alert, and there the evidence and my clinical experience line up well. I've ranked them by how reliably they help.
1
Fix sleep and protect your rhythm
Strong leverfoundationalNothing else works as well on a sleep-deprived nervous system. Poor and irregular sleep keep cortisol elevated and flatten the daily curve, and the relationship runs both ways.16 In fact, even a single night of partial or total sleep loss can raise cortisol the next evening by roughly 37–45%.16 Aim for 7–9 hours on a consistent schedule, get bright light in the morning to anchor your rhythm, and keep screens and late caffeine out of the evening. If I could change one thing for a stressed patient, it would be this. (See our Deep Sleep Protocol.)
Clinical takeaway: consistent, sufficient sleep is the single highest-yield way to restore a healthy cortisol curve.
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Move daily, but don't overtrain
Strong leverdose-dependentRegular low-to-moderate movement (walking, easy cycling, yoga, strength work) lowers baseline cortisol over time and improves how you handle stress. The catch is dose: chronic high-intensity overtraining without recovery raises cortisol instead. Most people benefit from more walking and gentler sessions, not from grinding themselves down.
Clinical takeaway: consistent moderate activity lowers cortisol; relentless overtraining does the opposite.
3
Train your nervous system to stand down
Strong levermeta-analysisCortisol responds directly to a calmed nervous system. A meta-analysis of mindfulness studies found that mindfulness practice measurably lowers cortisol.6 Slow breathing (a few minutes of long, slow exhales), prayer or meditation, and simply time in nature all down-regulate the stress response. Pick one you'll do daily; consistency beats intensity here.
Clinical takeaway: a daily down-regulation practice reliably reduces cortisol output, and the habit matters more than the method.
4
Eat to steady your blood sugar
Solid levermechanism + dietBlood sugar and cortisol are tied together: every crash is read by the body as a stressor, prompting another cortisol release. Build meals around protein, fiber, and healthy fat, lean on whole foods, and go easy on refined sugar. Then mind the two biggest cortisol provocateurs in a typical diet, excess caffeine and alcohol, both of which push cortisol up or scramble its rhythm. Caffeine alone, at about a 2–3 cup dose, can raise cortisol roughly 30%.17
Clinical takeaway: steadier blood sugar means fewer cortisol spikes; refined sugar, excess caffeine, and alcohol work against you.
5
Add targeted support: ashwagandha, magnesium, omega-3s
Helpful adjunctRCT-supportedSupplements are the finishing touch, not the foundation. The standout is ashwagandha, an adaptogen: in a randomized trial of chronically stressed adults, a standardized root extract lowered serum cortisol by about 28% over 60 days versus placebo,7 and a 2024 meta-analysis of randomized trials confirmed a significant pooled reduction in cortisol across studies.9 Magnesium supports the stress response and sleep,8 and omega-3s from fish oil may buffer cortisol reactivity. I reach for these to support the lifestyle changes above, never to replace them. (See our guide to magnesium glycinate.)
Clinical takeaway: ashwagandha has the best trial support for lowering cortisol; magnesium and omega-3s play supporting roles.
Ashwagandha lowered serum cortisol 27.9% in 60 days, against 7.9% on placebo
6
Tend relationships, laughter, and play
Underrated leveremergingConnection is physiology, not a nicety. Supportive relationships, laughter, and unstructured play all signal safety to the nervous system and are associated with lower cortisol. It's the lever people skip because it feels unserious, and the one many of my most stressed patients need most.
Clinical takeaway: social connection and downtime are genuine cortisol regulators, not optional extras.
Best foods to support healthy cortisol
The job of food here is to steady blood sugar and supply the raw materials your nervous system uses to calm down. These are the ones I lean on:
- Omega-3 fish like wild salmon, sardines, and mackerel buffer the stress response
- Magnesium-rich foods such as dark leafy greens, pumpkin seeds, and a little dark chocolate
- Quality protein from pasture-raised eggs, grass-fed meat, and legumes to blunt blood-sugar swings
- Healthy fats like avocado, olive oil, nuts, chia, and flax
- Colorful, polyphenol-rich produce such as blueberries, cherries, citrus, and leafy greens
- Calming herbal teas such as chamomile, tulsi (holy basil), lemon balm, and passionflower
- Fermented foods, for the gut–brain axis that helps regulate the stress response
Just as important is what to pull back: refined sugar, excess caffeine, and alcohol are the three biggest dietary cortisol provocateurs.
The top 7 supplements for cortisol support
These are the seven I reach for most, chosen on a mix of clinical evidence and long traditional use, and the adaptogens at the top have both. Doses are typical of the published trials, a starting reference rather than a prescription. Talk to your provider before starting any of them, especially if you're pregnant or nursing, take medication, or have a health condition.
| Supplement | Typical studied dose | Best for | Evidence & tradition | Key cautions |
|---|---|---|---|---|
| 300–600 mg/day | Stress-driven high cortisol, sleep | Strongest, from multiple RCTs and a meta-analysis; classic Ayurvedic adaptogen79 | Avoid in pregnancy; caution with thyroid and autoimmune conditions or medications |
| 200–600 mg/day | Stress fatigue, blunting the morning cortisol spike | Moderate, from RCTs (SHR-5 extract); traditional Russian and Scandinavian use13 | Can be stimulating, so take earlier in the day; caution with bipolar disorder or stimulants |
| 300–600 mg/day (or tea) | Everyday stress, blood-sugar balance | Emerging, from RCTs and a systematic review; revered Ayurvedic adaptogen14 | May lower blood sugar; caution with antidiabetic or blood-thinning medication |
| 200–400 mg/day | Sleep, stress, muscle tension | Moderate, from randomized trials8 | Reduce dose with kidney disease; can loosen stools |
| 100–200 mg | Acute stress, calm focus | Emerging, from RCTs (often acute); the calming amino acid in green tea15 | Generally very well tolerated; can add mild calm/drowsiness |
| 1–2 g/day | Stress reactivity, inflammation | Emerging; supports a calmer stress response | Caution with blood thinners |
| 300–600 mg/day | Exercise-induced and nighttime cortisol | Emerging, best studied in athletes and overtraining; 600 mg blunted exercise cortisol ~35%12 | Check medication interactions; most data are short-term |
A few rules I give patients: build the foundation first, since no supplement out-performs fixed sleep and a calmer nervous system. Give it time: adaptogens generally need 4–8 weeks of consistent use before the effect on your rhythm shows. And don't stack everything at once; I'd start with one adaptogen (usually ashwagandha) plus magnesium, then adjust. If your cortisol is low rather than high, none of these are the answer. See the note just below.
What if my cortisol is low?
The action query runs the other way here, so the answer is shorter and firmer: don't try to "raise" suspected low cortisol on your own. Low cortisol means adrenal insufficiency until proven otherwise, and the fix is diagnosis and, when needed, prescription replacement under a doctor, not an adaptogen or a salt-and-licorice protocol. While you get evaluated, the supportive basics still apply: protect sleep, keep blood sugar stable, favor gentle movement over hard training, and follow your provider's guidance on salt and fluids. If you take long-term steroids, never stop them abruptly.
How and when to test your cortisol
Quick answer
Test in the morning (6–8 a.m.), when cortisol peaks, for a single value. To see the whole daily rhythm, practitioners use a multi-sample salivary or dried-urine panel rather than one blood draw. Tell your provider about steroids, supplements, pregnancy, and illness, which all affect results.2
Morning blood draw
A single peak value; the standard first-line clinical test.
Salivary panel
Several samples across the day to map the daily curve.
Dried urine (DUTCH)
Cortisol plus its metabolites across the day.
Late-night / suppression tests
Doctor-ordered to confirm Cushing's or Addison's.
Timing is the whole game. A 7 a.m. draw and a 4 p.m. draw should look very different, so a result is only interpretable against the clock.2 A few practical notes: steroid medications, pregnancy, acute illness, and some supplements can shift cortisol or interfere with the assay, so list everything you take. And if you want a clean read of your baseline rhythm rather than a stress-test snapshot, ask whether a multi-sample salivary or dried-urine panel fits your situation better than a one-time blood draw.
Cortisol: the master stress hormone
Quick answer
Cortisol sits at the top of the body's stress system, so when it runs high for too long it pulls on nearly every other hormone, blunting thyroid (slowing the conversion of T4 to active T3), suppressing sex hormones and DHEA, raising insulin and blood sugar, and disrupting melatonin and sleep. This is why a stuck stress response rarely stays a "cortisol problem."
I think of cortisol less as one hormone among many and more as the conductor of the stress orchestra. In a real emergency, it's supposed to take over, raising blood sugar, lifting blood pressure, and quieting non-urgent systems, and then hand control back. The trouble with chronic stress is that cortisol never hands control back, and the systems it borrows from start to suffer:
- Thyroid: high cortisol slows the conversion of the storage hormone T4 into active T3 and shunts more of it toward inactive reverse T3, so you can have a "normal" TSH and still feel hypothyroid, which is why thyroid and stress symptoms so often blur together
- Sex hormones & DHEA: a chronically stressed system tends to run lower DHEA, progesterone, and testosterone, the pattern behind the "cortisol steal" below
- Insulin & blood sugar: cortisol raises blood sugar by design, and over time that drives higher insulin and more fat storage around the middle
- Melatonin & sleep: cortisol and melatonin are meant to seesaw, with cortisol high in the morning and melatonin high at night; a cortisol curve stuck high at night flattens that seesaw
The "cortisol steal," explained
In functional medicine you'll often hear about the cortisol steal (also called the "pregnenolone steal"). The idea: both cortisol and your other steroid hormones trace back to the same parent molecule, pregnenolone, and under relentless stress the body prioritizes cortisol, so DHEA and the sex hormones can run low.
1Pregnenolone
the shared precursor
2Chronic stress
Cortisol · prioritized under stress
3Downstream hormones can run low
DHEA · Progesterone · Testosterone & estrogen
Cortisol and the markers around it
Cortisol rarely tells the whole story alone. It's best read alongside DHEA-S, ACTH, thyroid (TSH and free T3), and fasting glucose/insulin, because the stress, thyroid, and blood-sugar systems all pull on one another.
| Marker | Why it pairs with cortisol |
|---|---|
DHEA-S | The adrenals' other major output; the cortisol-to-DHEA balance reflects overall stress load |
ACTH | The pituitary signal that drives cortisol; helps separate a pituitary cause from an adrenal one |
TSH / free T3 | Chronic stress can lower the conversion of T4 to active T3, so thyroid and adrenal symptoms overlap |
Fasting glucose / insulin | Cortisol raises blood sugar, and blood-sugar swings raise cortisol, a two-way street |
This is why I rarely chase a cortisol number in isolation. A "stuck on" stress system shows its fingerprints across these markers, such as a suppressed DHEA, a sluggish T3, or a creeping fasting glucose. Reading them together turns a confusing single result into a coherent picture.
Myths vs. facts
Myth
Cortisol is bad, and you want it as low as possible.
Fact
Cortisol is essential, and too little is dangerous. The goal is a healthy daily rhythm at the right levels.
Myth
A normal morning blood test means my cortisol is fine.
Fact
One value can miss a flat or reversed daily curve that tracks with real symptoms.
Myth
"Adrenal fatigue" is why I'm exhausted.
Fact
"Adrenal fatigue" isn't a recognized diagnosis. The rhythm can be disrupted, but true adrenal insufficiency is a separate, testable condition.
Myth
A cortisol supplement will fix high cortisol.
Fact
There's no such thing. You lower stress-driven cortisol with behavior; medical causes need medical care.
When to see a doctor
See a doctor, rather than self-treating, for any result well outside your lab's range, or for the red-flag symptoms below. Cortisol excess (Cushing's) and deficiency (Addison's) are both medical conditions that need prompt, professional evaluation.
See a doctor, and don't self-treat, if you have
Rapid central weight gain with a rounded face, purple stretch marks, or easy bruising
Persistently high blood pressure or blood sugar alongside these changes
Deep, unexplained fatigue with low blood pressure, dizziness, salt cravings, or darkening skin
Symptoms while taking long-term steroid medication, and never stop steroids abruptly
A cortisol result well outside your lab's reference range
Suspected Cushing syndrome or Addison's disease, both of which need prompt workup
You're pregnant or nursing, or take medication, before starting adaptogens like ashwagandha
The bottom line
Should you worry about your cortisol?
For most people, the issue is a stress hormone stuck "on," not a disease, with a rhythm flattened by sleep debt, blood-sugar swings, and a nervous system that never gets the all-clear. Read by the clock, the number tells you where you stand, and the fix is mostly upstream, through sleep, movement, daily down-regulation, steady fuel, and a few supportive nutrients like ashwagandha and magnesium.
The exceptions matter, though. A markedly high or low result, or any of the red-flag symptoms above, points to conditions that need a doctor, not a routine. Used the right way, as number plus rhythm plus symptoms together, cortisol is one of the most useful windows you have into how well your body is handling the load it's under.
Cortisol: frequently asked questions
What is a normal cortisol level?
For a morning blood test (6–8 a.m.), a normal cortisol level is typically about 10–20 mcg/dL, falling to roughly 3–10 mcg/dL by late afternoon. Ranges vary by lab, test type, and time of day, so cortisol is always interpreted against when the sample was taken.
What are the symptoms of high cortisol?
Common signs include weight gain around the face and midsection, a rounded face, easy bruising, high blood pressure, high blood sugar, muscle weakness, poor sleep, anxiety or irritability, and brain fog. Very high cortisol can indicate Cushing syndrome and needs medical evaluation.
What are the symptoms of low cortisol?
Low cortisol can cause persistent fatigue, low blood pressure, dizziness on standing, salt cravings, low blood sugar, weight loss, and (in Addison's disease) darkening of the skin. Low cortisol should be evaluated by a doctor.
How can I lower my cortisol naturally?
Protect sleep and your daily rhythm, use low-to-moderate exercise rather than chronic overtraining, practice daily stress down-regulation (meditation, slow breathing, time in nature), steady your blood sugar with whole foods, and limit excess caffeine and alcohol. Adaptogens like ashwagandha and minerals like magnesium have trial support.
When is the best time to test cortisol?
Morning, usually between 6 and 8 a.m., when cortisol peaks. To assess the full daily rhythm, practitioners often use a salivary or dried-urine panel with several samples across the day rather than a single blood draw.
Does a normal cortisol blood test rule out a problem?
Not entirely. A single in-range value can miss a disrupted daily rhythm, which is why a flat or reversed curve across the day can matter even when a one-time morning number looks normal. Symptoms and the pattern across the day are interpreted together.
What causes high cortisol?
The most common driver is chronic psychological or physiological stress. Other causes include long-term steroid (glucocorticoid) medication, and less commonly Cushing syndrome from a pituitary or adrenal tumor. Poor sleep, alcohol, and blood-sugar swings also push cortisol up.
Can ashwagandha lower cortisol?
Several randomized trials in stressed adults have reported meaningful reductions in serum cortisol with standardized ashwagandha extract over 6–8 weeks. It's best viewed as supportive for stress-driven elevations, not a treatment for medical causes like Cushing syndrome.
What time of day is cortisol highest and lowest?
Cortisol is highest in the early morning, peaking roughly 30–45 minutes after you wake (the cortisol awakening response), and lowest around midnight. This daily rhythm is why a cortisol result only means something when read against the time the sample was taken.
Can stress cause high cortisol?
Yes. Chronic psychological and physiological stress is by far the most common cause of elevated cortisol. Poor sleep, blood-sugar swings, excess caffeine and alcohol, and chronic overtraining all keep cortisol elevated and can flatten its normal daily curve.
What foods help lower cortisol?
Foods that steady blood sugar help most: protein, fiber, and healthy fats such as fatty fish (omega-3s), eggs, nuts and seeds, leafy greens, avocado, and magnesium-rich foods like dark leafy greens and dark chocolate. Limiting refined sugar, excess caffeine, and alcohol matters as much as what you add.
Does coffee raise cortisol?
Caffeine can raise cortisol, especially in large amounts, on an empty stomach, or late in the day. In controlled studies, a 2–3 cup dose raised it about 30%. Most people do fine with moderate coffee taken with or after breakfast; the bigger problems are very high intake and afternoon or evening caffeine that disrupts sleep and the cortisol rhythm.
How do I prepare for a cortisol test?
A standard cortisol blood test is usually drawn in the morning, often around 8 a.m. Tell your provider about any steroid medication, supplements (including biotin and licorice), pregnancy, recent illness, or shift work, since all can affect the result. For a salivary or dried-urine panel you collect several samples across the day at set times.
Can high cortisol cause belly fat?
Yes. Chronically high cortisol promotes fat storage around the abdomen and raises blood sugar, which is why stubborn belly fat is one of the classic signs of an elevated, stress-driven cortisol pattern. Addressing sleep, stress, and blood sugar tends to help more than any single food or supplement.
Can high cortisol cause anxiety and insomnia?
Often, yes. Cortisol that stays elevated or peaks at the wrong time of day is linked with anxiety, irritability, and the "wired but tired" pattern of trouble falling or staying asleep. A cortisol curve that should be low at night but isn't can keep the nervous system switched on when it should be winding down.
Does fasting raise cortisol?
Short, moderate fasting is a mild stressor and can nudge cortisol up modestly, which is usually harmless in healthy people. Aggressive or prolonged fasting, especially combined with poor sleep, hard training, or being underweight, can push cortisol higher and disrupt its rhythm. If fasting leaves you wired, anxious, or sleeping poorly, it may not suit your current stress load.
Is cortisol the same as "adrenal fatigue"?
No. "Adrenal fatigue" is a popular term for stress-related symptoms with a disrupted cortisol rhythm, but it isn't a recognized medical diagnosis. True adrenal insufficiency (Addison's disease) is a distinct, diagnosable condition with very low cortisol that requires treatment.
Freshness & update log
October 19, 2026 — Rebuilt the page as Dr. Axe's updated guide, with sources checked and links to related DrAxe.com pages added.
Last medically reviewed — June 1, 2026 by the DrAxe.com Medical Advisory Board.
Updated June 8, 2026. — Added a "cortisol: the master stress hormone" section covering its effect on thyroid, sex hormones, insulin, and sleep, with a "cortisol steal" explainer; added two diagrams (the HPA-axis cortisol cascade and the cortisol steal); expanded the supplement guidance to a sourced top 7 (ashwagandha, rhodiola, holy basil, magnesium, L-theanine, omega-3s, phosphatidylserine) with doses and cautions; added a "standard vs. optimal cortisol" comparison, a "what your result means & what to do next" table, a best-foods section, SI (nmol/L) unit conversions, and expanded FAQs. References now include the Endocrine Society Cushing's and adrenal-insufficiency guidelines and trials for each supplement listed.
Published June 2026. — Includes time-of-day reference ranges across blood, saliva, and 24-hour urine; interpretation anchors for adrenal insufficiency (morning serum <3 mcg/dL suggestive, >15–18 mcg/dL largely excludes); high- and low-cortisol symptom and cause lists; an evidence-ranked "how to lower cortisol" section with a folded low-cortisol note; testing methods and timing; and related-marker pairing (DHEA-S, ACTH, TSH/free T3, fasting glucose). Uses the lab-marker template, a reference-range interpretation panel in place of the supplement Dr. Axe Score.
References
- Cleveland Clinic. Cortisol: What It Is, Function, Symptoms & Levels. my.clevelandclinic.org
- Cleveland Clinic. Cortisol Test: What It Is, Purpose, Types & Results. my.clevelandclinic.org
- NIH, National Library of Medicine, MedlinePlus. Cortisol Test. medlineplus.gov
- Clow A, Hucklebridge F, Stalder T, et al. The cortisol awakening response: more than a measure of HPA axis function. Neurosci Biobehav Rev. 2010;35(1):97-103. PMID:20026350
- UCSF Health. Cortisol blood test, normal values and interpretation. ucsfhealth.org
- Pascoe MC, Thompson DR, Jenkins ZM, Ski CF. Mindfulness mediates the physiological markers of stress: a systematic review and meta-analysis. J Psychiatr Res. 2017;95:156-178. PMID:28863392
- Chandrasekhar K, Kapoor J, Anishetty S. A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults. Indian J Psychol Med. 2012;34(3):255-262. PMID:23439798
- Boyle NB, Lawton C, Dye L. The effects of magnesium supplementation on subjective anxiety and stress: a systematic review of randomised clinical trials. Nutrients. 2017;9(5):429. PMID:28445426
- Arumugam V, Vijayakumar V, Balakrishnan A, et al. Effects of ashwagandha (Withania somnifera) on stress and anxiety: a systematic review and meta-analysis. Explore (NY). 2024;20(6):103062. ScienceDirect
- Bornstein SR, Allolio B, Arlt W, et al. Diagnosis and treatment of primary adrenal insufficiency: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2016;101(2):364-389. PMID:26760044
- Nieman LK, Biller BMK, Findling JW, et al. The diagnosis of Cushing's syndrome: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2008;93(5):1526-1540. PMID:18334580
- Starks MA, Starks SL, Kingsley M, et al. The effects of phosphatidylserine on endocrine response to moderate intensity exercise. J Int Soc Sports Nutr. 2008;5:11. PMID:18662395
- Olsson EM, von Schéele B, Panossian AG. A randomised, double-blind, placebo-controlled, parallel-group study of the standardised extract SHR-5 of the roots of Rhodiola rosea in the treatment of subjects with stress-related fatigue. Planta Med. 2009;75(2):105-112. PMID:19016404
- Jamshidi N, Cohen MM. The clinical efficacy and safety of tulsi (Ocimum tenuiflorum / holy basil) in humans: a systematic review of the literature. Evid Based Complement Alternat Med. 2017;2017:9217567. PMID:28400848
- Hidese S, Ogawa S, Ota M, et al. Effects of L-theanine administration on stress-related symptoms and cognitive functions in healthy adults: a randomized controlled trial. Nutrients. 2019;11(10):2362. PMID:31623400
- Leproult R, Copinschi G, Buxton O, Van Cauter E. Sleep loss results in an elevation of cortisol levels the next evening. Sleep. 1997;20(10):865-870. academic.oup.com
- Lovallo WR, al'Absi M, Blick K, Whitsett TL, Wilson MF. Stress-like adrenocorticotropin responses to caffeine in young healthy men. Pharmacol Biochem Behav. 1996;55(3):365-369. PMID:8951977
Medically reviewed by the DrAxe.com Medical Advisory Board on Jun 1, 2026.
DrAxe.com may earn a commission on tests or supplements linked in this article, including products from brands Dr. Axe is affiliated with. This does not influence which research is cited or how evidence is presented. Our editorial and medical-review processes are independent of commercial relationships.
This content is for educational purposes only and is not medical advice. Cortisol abnormalities can signal serious conditions, so always ask a qualified healthcare provider to interpret your results, especially if you are pregnant, nursing, taking medication (including steroids), or managing a health condition.