Low Cortisol: What Happens When the Stress Hormone Runs Short, and Why It Is Not ‘Adrenal Fatigue’

A saliva kit arrives in a padded envelope. Four little tubes, a color-coded chart, and a promise that by Friday the sender will know whether her ‘adrenals are exhausted.’ She ordered it after a 40-second video told her that low cortisol explained the 3 p.m. slump, the salt cravings, and the fact that coffee no longer worked. As of spring 2026, that video has plenty of company: searches for low cortisol have climbed alongside a wave of ‘cortisol face,’ ‘cortisol cocktail,’ and ‘adrenal fatigue’ content, and a steady stream of supplement ads built on all three.

The timing is not entirely frivolous. In 2024, an international endocrine guideline drew new attention to a very real and under-recognized form of low cortisol, the kind that follows long courses of steroid medicines. So two conversations are running at once: one about a serious, testable hormone deficiency, and one about a label no endocrinologist uses.

This piece separates them, and explains why the difference is not academic.

What is low cortisol, and what does cortisol actually do?

Cortisol is a steroid hormone made by the two adrenal glands, each about the size of a walnut, sitting like small caps on top of the kidneys. It is often called the stress hormone, which undersells it. Cortisol keeps blood pressure from collapsing, releases glucose so the brain has fuel between meals, dampens inflammation, and helps the body absorb the shock of surgery, infection, or injury. Without it, an ordinary stomach bug can become a medical emergency.

Production follows a daily rhythm. Levels rise sharply in the hour before waking, peak around 30 to 45 minutes after you get up, then drift down through the day to their lowest point near midnight. The whole system is run by a chain of command: the hypothalamus in the brain releases CRH, the pituitary gland below it responds with ACTH, and ACTH tells the adrenals to make cortisol. Endocrinologists call this the HPA axis. Cortisol then feeds back to the brain to switch the signal off, a thermostat rather than a tap.

Low cortisol, in medical terms, means the adrenals cannot produce enough hormone to meet the body’s needs, even when properly stimulated. The formal name is adrenal insufficiency. It is rare, with most Western estimates landing between roughly 1 in 10,000 and 1 in 100,000 people for the autoimmune form, and it is defined by measurement, not by a symptom score.

That distinction matters because tiredness is universal and adrenal insufficiency is not. A hormone that responds to every late night and every skipped lunch will fluctuate in healthy people all day long. Fluctuation is physiology. Deficiency is disease. The rest of this article is about telling the two apart.

What changed recently in the low cortisol conversation

Three developments explain why this topic is busy right now, and only one of them is medical.

The first is the 2024 joint guideline from the European Society of Endocrinology and the Endocrine Society on glucocorticoid-induced adrenal insufficiency, the form of low cortisol caused by steroid medicines themselves. Its central message was that anyone who has taken a glucocorticoid such as prednisone for more than three to four weeks may have a suppressed HPA axis, and that stopping abruptly can be dangerous. The guideline pushed for gradual tapering under supervision and for patient education rather than routine blood testing in most cases. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) lists sudden withdrawal of steroid medicines among the recognized causes of secondary adrenal insufficiency, and this guideline sharpened that point for prescribers.

The second is a shift in what patients are seeing online. Through 2024 and 2025, short-form video popularized ‘cortisol face,’ ‘cortisol belly,’ and homemade ‘cortisol cocktails’ of juice and salt. Most of that content is about supposedly high cortisol. Yet it created a shared vocabulary that supplement marketers have folded into the older ‘adrenal fatigue’ pitch, so that low cortisol and high cortisol are now blamed for the same puffiness and the same exhaustion, sometimes in the same feed.

The third is that the medical position has not moved at all. Harvard Health’s explainer on adrenal fatigue, published in 2018 and still current, notes that a systematic review of 58 studies found no evidence the condition exists, and no mainstream body has adopted the term since. What changed is the volume of the claim, not the strength of the evidence behind it.

What are the symptoms of low cortisol levels?

Adrenal insufficiency usually announces itself slowly, over months, which is part of why it gets missed. The pattern described by the NHS and Mayo Clinic is consistent: a deep fatigue that rest does not fix, muscle weakness, loss of appetite, unintended weight loss, nausea or abdominal pain, and lightheadedness on standing because blood pressure has fallen. Many people crave salt intensely. Blood sugar can dip, producing shakiness or brain fog, particularly after long gaps between meals.

Mood changes are common and easy to misattribute. Irritability, low mood, and a flattened motivation appear in a large share of people before diagnosis. The cause is physiological, not psychological: the brain is short on both glucose and a hormone it uses to regulate arousal.

One sign belongs to the primary form alone. When the adrenal glands themselves fail, the pituitary pumps out extra ACTH to try to rouse them, and a fragment of that molecule stimulates melanin. The result is a bronzing of the skin that looks like a tan the person never earned, most visible in skin creases, on the knuckles, in old scars, on the gums, and around the lips. Addison’s disease, the classic autoimmune form of primary adrenal insufficiency, is the textbook example. Secondary forms, where the pituitary is the problem, do not produce this darkening because ACTH is low, not high.

The list is long and every item on it overlaps with anemia, depression, thyroid disease, celiac disease, chronic infection, and simple sleep loss. That overlap is the whole point. Symptoms raise the question; only laboratory testing answers it. A person with three of these complaints has a reason to see a clinician. They do not yet have a diagnosis.

What causes low cortisol? Primary, secondary, and tertiary adrenal insufficiency

Doctors sort low cortisol by where in the chain of command the fault lies.

Primary adrenal insufficiency means the adrenal glands are damaged. In high-income countries, roughly 70 to 90 percent of cases are autoimmune, the body’s own immune system destroying the cortex of the gland; this is Addison’s disease. Worldwide, tuberculosis remains a major cause. Rarer triggers include bleeding into the adrenals during severe infection, fungal infections, cancer spreading to the glands, surgical removal, and inherited disorders such as congenital adrenal hyperplasia, in which an enzyme needed to make cortisol is missing from birth. Because the gland also makes aldosterone, the salt-retaining hormone, primary disease usually brings low sodium, high potassium, and marked low blood pressure along with it.

Secondary adrenal insufficiency means the pituitary is not sending enough ACTH. Causes include pituitary tumors, surgery or radiation to the region, head injury, severe blood loss after childbirth, and, increasingly, immune checkpoint inhibitor cancer drugs that inflame the pituitary. Aldosterone is spared here, so salt balance is usually normal.

Tertiary adrenal insufficiency means the hypothalamus has stopped signaling, and by far its commonest cause is glucocorticoid medicine. Prednisone tablets, dexamethasone, high-dose inhaled steroids for asthma, potent skin creams over large areas, and repeated joint injections all tell the brain that cortisol is plentiful, so the brain stops asking for it. Over weeks the adrenals shrink from disuse. Stop the medicine abruptly and there is a gap before the system restarts. Long-term opioid use can suppress the axis in the same way.

This last category, taken together, is the most common cause of low cortisol in clinical practice, and the one most people have never heard of.

Can low cortisol levels be caused by stress?

This is the question behind most of the searches, and the honest answer is: not in the way the videos describe.

Psychological stress raises cortisol. That is the hormone’s job. In acute stress the surge is brief; in chronic stress, such as caregiving or shift work, research using repeated saliva samples shows a flattened daily curve in some people, with a blunted morning peak and a slightly elevated evening level. This is a change in rhythm, measured in groups, and it is associated with poorer sleep and metabolic health in observational studies. It is not a deficiency. The glands are working; the timing has drifted.

The ‘adrenal fatigue’ theory proposes something different: that years of stress wear the adrenals out until they cannot make enough hormone. There is no anatomical or laboratory support for this. Healthy adrenals do not run down like a battery. In people whose HPA axis has genuinely failed, the failure has a demonstrable cause: autoimmune destruction, a tumor, surgery, tuberculosis, or a drug. Stress is not on that list in any mainstream source, including NIDDK, Mayo Clinic, and the NHS.

There is one place where stress and low cortisol truly meet, and it runs in the opposite direction. A person who already has adrenal insufficiency cannot mount a cortisol response to physical stress, so an infection, an accident, or surgery can tip them into crisis. Stress does not cause the deficiency; the deficiency makes stress dangerous.

Feeling wrecked after a brutal year is real and deserves care. Burnout, depression, and insomnia each have their own evidence-based management. Attaching them to a gland that is functioning normally delays that care and sends money toward products that cannot help.

Why doctors do not diagnose 'adrenal fatigue'

The phrase was coined in the late 1990s by a chiropractor, not through clinical research, and it has never been accepted by any endocrine society, national health service, or medical dictionary. Harvard Health puts it plainly: it is not an accepted medical diagnosis. The Endocrine Society has said the same.

The core problem is that the theory makes a prediction that fails when tested. If stress wore out the adrenals, people reporting exhaustion should show measurably lower cortisol or a weaker response to ACTH stimulation than people who feel fine. The 2016 systematic review Harvard cites pooled 58 studies of exactly this question and found no consistent difference. Some studies found lower morning cortisol in tired people, others found higher, and most found none. Methods varied so widely that the reviewers could not even define what a positive test would look like.

Symptoms are the second problem. The lists used by adrenal fatigue practitioners are so broad that almost anyone qualifies: tiredness, difficulty waking, cravings, needing caffeine, feeling low, poor concentration. These describe the human condition on a Tuesday. A diagnosis that fits everyone rules nothing out.

The tests are the third. Home saliva panels marketed for adrenal fatigue measure real cortisol, but they are interpreted against invented ‘optimal’ ranges rather than validated thresholds, and single saliva readings swing with sleep, meals, exercise, and mood. They are not part of any diagnostic pathway for adrenal insufficiency.

Finally there is harm. The usual remedy sold alongside the label is a mix of ‘adrenal support’ supplements, some of which contain dried animal adrenal gland or undeclared steroid hormones. Taking these can suppress a healthy HPA axis, can cause the very deficiency being feared, and can distort future blood tests. Clinicians are not dismissive of the fatigue. They are unwilling to name a disease the evidence cannot find.

How is low cortisol diagnosed?

The workup is orderly and, for most people, quick.

It begins with a blood test drawn in the early morning, ideally around 8 a.m., when cortisol should be at its highest. MedlinePlus explains that timing is everything here: an afternoon value is expected to be low and proves little. A clearly low morning result in a symptomatic person strongly suggests insufficiency; a clearly normal one usually rules it out; an in-between value calls for the next step. Reference ranges differ between laboratories, so the number is always read against the lab that produced it.

The next step is the ACTH stimulation test. A synthetic form of ACTH called cosyntropin is given by injection, and cortisol is measured before and again 30 and 60 minutes afterward. Healthy adrenals respond with a brisk rise. Failed glands cannot. The test can be done in a clinic in an hour and is the standard confirmatory test in the United States, the United Kingdom, and most guidelines.

A blood ACTH level drawn at the same time as the morning cortisol sorts the type. High ACTH with low cortisol points to the adrenal glands themselves (primary). Low or normal ACTH with low cortisol points to the pituitary or hypothalamus (secondary or tertiary). Sodium, potassium, glucose, renin, and aldosterone add detail; antibodies against the adrenal enzyme 21-hydroxylase confirm the autoimmune cause. If the pituitary is implicated, an MRI of the head and tests of its other hormones follow.

Two things are absent from this pathway: hair or saliva panels sold direct to consumers, and any questionnaire. A diagnosis of adrenal insufficiency rests on a stimulation test read by a clinician who knows the person’s medication history. Nothing purchased online substitutes for that.

Adrenal insufficiency vs. adrenal fatigue vs. burnout: a side-by-side

Three labels circulate for the same complaint of exhaustion. Only one is a hormone disorder, and the differences are sharp once laid out.

	Adrenal insufficiency	‘Adrenal fatigue’	Burnout
Recognized diagnosis?	Yes, in every major guideline	No	Yes, as an occupational phenomenon (WHO ICD-11), not a disease
What is wrong	Adrenals, pituitary, or hypothalamus cannot make or signal for cortisol	Claims adrenals are ‘worn out’ by stress	Chronic workplace stress not successfully managed
Cortisol on testing	Low morning level; fails to rise on ACTH stimulation	Normal, or normal variation	Normal or mildly altered rhythm in some studies
Distinguishing features	Weight loss, low blood pressure, low sodium, skin darkening (primary)	None specific	Cynicism about work, reduced efficacy, exhaustion
Danger if untreated	Adrenal crisis; can be fatal	Not a physical threat; risk comes from unregulated supplements	Depression, cardiovascular risk over time
Management	Lifelong prescribed hormone replacement	No validated treatment; supplements not recommended	Workload change, sleep, psychological therapy, medical review

Two rows deserve a second look. The testing row is the decisive one: adrenal insufficiency is the only condition of the three that changes what a laboratory finds. The danger row is why clinicians push back on the middle column. A person with true insufficiency who accepts the adrenal fatigue label and buys supplements instead of seeing an endocrinologist is at risk of a preventable emergency. A person with burnout who does the same loses months that could have gone into changes that actually help.

Burnout, for its part, is not imaginary, and the World Health Organization gave it a formal definition precisely so it could be studied. It simply lives in a different chapter of the manual.

How is low cortisol treated?

Once adrenal insufficiency is confirmed, treatment is replacement: giving back the hormone the body cannot make, in a pattern that copies the natural daily rhythm as closely as tablets allow.

The usual medicine is hydrocortisone, which is chemically identical to cortisol. Some people are prescribed prednisolone or, less often, dexamethasone, which last longer in the body. Tablets are typically split across the day, with the largest share on waking to imitate the morning peak, but the schedule, the amount, and any adjustments belong entirely to the prescribing endocrinologist and are tuned to the individual over months.

People with primary disease usually also need fludrocortisone, which replaces aldosterone and keeps sodium and blood pressure stable. Clinicians follow it with blood pressure checks, electrolytes, and renin levels. Some women with Addison’s are offered DHEA replacement for energy and mood, though the evidence for benefit is mixed and the decision is individual.

Replacement is lifelong for autoimmune and structural causes. For glucocorticoid-induced insufficiency, the axis often recovers over weeks to many months once the steroid is tapered, and the treating team retests to decide when replacement can stop. No one should attempt that taper on their own; the 2024 guideline exists because abrupt stopping has caused avoidable crises.

Two pieces of the treatment are not pills. Every person with adrenal insufficiency is taught ‘sick day rules,’ a written plan from their team for temporarily increasing hydrocortisone during fever, vomiting, injury, or surgery, because their body cannot do so itself. And every person carries an emergency hydrocortisone injection kit and a steroid alert card or medical bracelet so that paramedics know what to give. Family members are trained to use the kit. This preparation, more than any tablet, is what keeps the condition manageable.

What the evidence actually says, and how strong it is

Grading the evidence keeps this topic honest, because the strength varies enormously across the claims people encounter.

That adrenal insufficiency exists and is fatal untreated: very strong. This rests on 170 years of pathology since Thomas Addison described the disease in 1855, on consistent physiology, and on mortality data from the era before hydrocortisone became available in the 1950s. No randomized trial of replacement against placebo has ever been run, because withholding treatment would be unethical. The evidence is observational and mechanistic, and it is as settled as anything in endocrinology.

That replacement should mimic the daily rhythm: moderate. Randomized crossover trials comparing conventional divided-dose hydrocortisone with modified-release formulations show modest improvements in some metabolic and quality-of-life measures, with mixed results across studies. Guidelines endorse the principle; the best way to achieve it remains under study.

That long steroid courses suppress the axis: strong. This is supported by decades of observational cohorts and prospective studies measuring recovery after steroid withdrawal, which is why the 2024 guideline could be firm about tapering and education.

That chronic stress alters cortisol rhythm: moderate, observational. Many studies find flattened curves in high-stress groups; they cannot prove direction of cause, and the changes are subtle.

That stress causes adrenal deficiency (‘adrenal fatigue’): absent. The 58-study systematic review found no reliable marker. This is the lowest tier of evidence there is: a hypothesis that has been tested and has not held.

That supplements raise or normalize cortisol: absent to weak. Small trials of licorice, ashwagandha, or vitamin C report changes in stress ratings or saliva readings in healthy volunteers; none shows treatment of adrenal insufficiency, and licorice can raise blood pressure and lower potassium.

Readers deserve to know which shelf a claim sits on. The gap between the top and bottom of this list is the gap between medicine and marketing.

How do you fix low cortisol naturally?

It is the second most searched question on this topic, so it deserves a direct answer rather than a dodge: if a clinician has confirmed adrenal insufficiency, there is no natural method that restores cortisol production. Damaged adrenal tissue does not regrow, and a pituitary that has stopped signaling does not respond to diet. Replacement hormone is the treatment, and the people who live longest and best with this condition are the ones who take it as prescribed and carry their emergency kit.

That said, lifestyle still matters, in two different ways depending on which group you are in.

For people with diagnosed insufficiency, the useful habits are the ones that reduce the frequency and severity of stressors the body cannot buffer on its own. Staying current with recommended vaccinations lowers the odds of the infections that most often trigger crises. Regular meals prevent the blood sugar dips that hit harder without cortisol. Adequate salt intake, as advised by the treating team, supports blood pressure in the primary form. Consistent sleep helps the medication schedule align with the body’s residual rhythm. None of these replaces a tablet; each makes the tablet’s job easier.

For people who feel exhausted and have normal test results, the honest news is better than the marketing suggests. Sleep, daylight exposure in the morning, regular physical activity, limiting alcohol, and treating any depression, anxiety, or sleep apnea all shift the HPA axis toward a healthier rhythm in observational and small trial data. These are the interventions that address the fatigue itself.

What does not help either group is ‘adrenal support’ supplements. Products containing glandular extracts have been found on testing to contain steroid hormones, and taking them can suppress a healthy axis. Anyone tempted should discuss it with their clinician first, and anyone already taking one should mention it before any cortisol test, because it can invalidate the result.

Common myths about low cortisol, corrected

Myth: If I am always tired, my adrenals are probably depleted. Fatigue is the single commonest reason people see a doctor, and adrenal insufficiency accounts for a tiny fraction of it. Anemia, thyroid disease, sleep disorders, depression, and medication side effects are each far more likely. Cortisol testing is reasonable when symptoms fit the full picture; assuming the answer before the test is how other diagnoses get missed.

Myth: Low cortisol is good because cortisol is the ‘bad’ stress hormone. Cortisol is essential. Too little is as dangerous as too much, and faster. People with untreated adrenal insufficiency die of shock, not of calm. The goal is normal, not low.

Myth: A saliva test can tell me if my cortisol is low. Saliva cortisol has a legitimate use, mainly a late-night sample to screen for excess cortisol in Cushing’s syndrome. It is not validated for diagnosing deficiency, and consumer panels compare results against ranges no guideline recognizes.

Myth: I can fix it with adaptogens and salt water. Salt helps blood pressure in confirmed primary disease and is part of medical advice there. It does not make cortisol. No herb has been shown to treat adrenal insufficiency.

Myth: Steroid inhalers and creams are too weak to affect cortisol. At high doses over long periods, both have been documented to suppress the HPA axis, especially in children. This is not a reason to stop a prescribed inhaler, which would be far more dangerous; it is a reason to keep prescribers informed about every steroid product being used.

Myth: Once diagnosed, life is a cascade of emergencies. With replacement, sick-day planning, and an emergency kit, most people with adrenal insufficiency work, travel, exercise, and have children. Mayo Clinic and the NHS both describe it as a lifelong but manageable condition, and that description is accurate.

Living well with adrenal insufficiency day to day

The first months after diagnosis are mostly about learning a new relationship with illness. A cold that would once have meant a slow week now means following the written plan from your team, watching for vomiting, and knowing when the tablets are no longer enough and the injection is. Most people describe a period of anxiety about this, followed by a settling as the routines become automatic.

Practical anchors help. Keeping medication in more than one place, so a lost bag on holiday is an inconvenience rather than a crisis. Setting phone alarms for each dose until the timing is habit. Wearing a medical alert bracelet and carrying the steroid card in a wallet, because a paramedic who finds an unconscious person with low blood pressure needs to know within seconds why. Telling a partner, a close colleague, or a roommate where the emergency kit lives and showing them how it works. Dentists, surgeons, and anesthetists need to know before any procedure, since cortisol needs rise sharply with surgery and the team will plan cover in advance.

Exercise is encouraged. Prolonged or intense sessions may prompt a conversation with the endocrinologist about adjustments, but ordinary activity requires none. Travel is routine with planning: medication in hand luggage, a letter explaining the injection kit for airport security, and awareness of how time-zone shifts interact with dosing schedules, which the treating team can map out.

Mental health deserves attention. Living with a condition that turns every fever into a decision is wearing, and low mood is more common in adrenal insufficiency than in the general population. Some of that lifts as replacement is optimized; some benefits from counseling or peer support. Endocrine teams expect these conversations and are used to having them.

Regular follow-up, usually once or twice a year when stable, checks weight, blood pressure, electrolytes, bone density in some cases, and whether the current regimen still fits the person’s life. Adrenal insufficiency is a chronic condition, and chronic conditions are lived in ordinary time, not in emergency rooms.

When to see a doctor about low cortisol

Two very different thresholds apply here, and knowing which one you are near is the most useful thing this article can offer.

Book a routine appointment if fatigue has lasted more than a few weeks and comes with any of the following: unintended weight loss, dizziness or fainting on standing, persistent nausea or loss of appetite, new salt craving, or darkening of the skin in creases, scars, or gums. Mention every steroid product you use or have recently stopped, including inhalers, creams, joint injections, and any ‘adrenal’ or ‘glandular’ supplement. A morning cortisol blood test is simple to arrange, and a normal result frees you and your clinician to look at the far more likely explanations.

Seek emergency care immediately, by calling emergency services, if you or someone with known adrenal insufficiency, or on long-term steroids, develops the signs of adrenal crisis. Mayo Clinic and the NHS list these as: severe weakness or inability to stand, repeated vomiting or diarrhea, severe abdominal, low back, or leg pain, confusion or unusual drowsiness, a fast heartbeat with very low blood pressure, cold clammy skin, or loss of consciousness. If an emergency hydrocortisone kit is available, use it as trained while help is on its way; it is safe to give and dangerous to withhold. Adrenal crisis is treated with intravenous hydrocortisone, fluids, and glucose in hospital, and outcomes are excellent when treatment is prompt.

Contact your endocrine team the same day if you have adrenal insufficiency and cannot keep tablets down, have a fever that is not settling, or are about to have surgery or a dental procedure they do not know about.

Every decision about testing, starting, adjusting, or stopping hormone replacement belongs to the prescribing clinician who knows your history. Never alter a steroid medicine on your own, and never stop one because a video suggested your body would recalibrate. It will not, and the consequences can arrive within days.

Frequently asked questions

Can low cortisol levels be caused by stress?

No, chronic stress does not cause adrenal insufficiency. Stress raises cortisol, and in long-term stress some people show a flattened daily rhythm on repeated testing, but the glands still work. True deficiency comes from autoimmune damage, tumors, surgery, infection such as tuberculosis, or long steroid medicine use. Stress does become dangerous in the other direction: someone who already has adrenal insufficiency cannot respond to illness or injury normally.

What are the symptoms of low cortisol levels?

The typical picture is fatigue that rest does not relieve, unintended weight loss, loss of appetite, nausea, dizziness on standing from low blood pressure, salt craving, low mood, and shakiness from low blood sugar. In primary adrenal insufficiency the skin darkens in creases, scars, and gums. Because each symptom overlaps with common conditions like anemia or thyroid disease, only blood testing confirms the diagnosis.

How do you fix low cortisol naturally?

Confirmed adrenal insufficiency cannot be reversed with diet, herbs, or lifestyle; the treatment is prescribed hormone replacement for as long as the deficiency lasts. Healthy habits still help by reducing infections and blood sugar swings that stress the body. If tests are normal and fatigue persists, sleep, morning daylight, exercise, and treating depression or sleep apnea address the tiredness itself. Supplements marketed for adrenals are not recommended.

Is low cortisol good?

No. Cortisol is often called the stress hormone, but the body needs it to hold up blood pressure, keep blood sugar steady, and survive infection or injury. Too little is life-threatening and can cause adrenal crisis within days of a triggering illness. The healthy goal is a normal level with a normal daily rhythm, not a low one. Anyone hoping to lower cortisol should discuss it with a clinician first.

What is a normal morning cortisol level?

Reference ranges differ between laboratories, so a result is always read against the lab that produced it. In general, a clearly normal 8 a.m. value in a symptomatic person makes adrenal insufficiency unlikely, a clearly low one strongly suggests it, and an in-between value leads to an ACTH stimulation test. Timing matters: afternoon or evening cortisol is naturally low and proves little on its own.

Can low cortisol cause anxiety or depression?

It can contribute. Low mood, irritability, and reduced motivation are common before adrenal insufficiency is diagnosed, partly because the brain is short of both glucose and a hormone that helps regulate arousal. Many people notice mood improving once replacement is established. Anxiety and depression are far more often unrelated to cortisol, so persistent symptoms deserve their own evaluation and treatment regardless of hormone results.

Can steroid inhalers or creams cause low cortisol?

Yes, at high doses used over long periods they can suppress the HPA axis, a risk documented especially in children and in people using several steroid products at once. This is not a reason to stop a prescribed inhaler, which would be more dangerous. It is a reason to tell every prescriber about all steroid medicines being used and to raise any concerns with the treating clinician.

What is the difference between Addison's disease and adrenal insufficiency?

Adrenal insufficiency is the umbrella term for any low cortisol state. Addison’s disease is the primary form in which the adrenal glands themselves are damaged, most often by autoimmune attack, so aldosterone is also lost and skin darkening appears. Secondary and tertiary forms stem from the pituitary or hypothalamus, most commonly after long steroid medicine use, and spare aldosterone. Treatment differs accordingly.

Does low cortisol cause weight gain?

No. Adrenal insufficiency typically causes weight loss, through appetite loss, nausea, and salt and fluid depletion. Weight gain around the trunk and face is a feature of excess cortisol, as in Cushing’s syndrome, or of over-replacement in someone on treatment. Online claims that both high and low cortisol produce ‘cortisol belly’ are not supported by the evidence and blur two opposite conditions.

Are at-home saliva cortisol tests reliable for detecting low cortisol?

Not for this purpose. Saliva cortisol has a validated role in a late-night sample to screen for excess cortisol, but it is not part of any guideline pathway for diagnosing deficiency. Consumer panels interpret results against ‘optimal’ ranges no medical body recognizes, and single readings swing with sleep, meals, and exercise. Diagnosis requires a morning blood cortisol and usually an ACTH stimulation test.

References

• Adrenal Insufficiency & Addison's Disease: NIDDK, National Institutes of Health
• Cortisol Test: MedlinePlus
• Addison's disease: NHS
• Cortisol: What It Is, Function, Symptoms & Levels: Cleveland Clinic

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.