How to Lower Cortisol — and Why “Adrenal Fatigue” Is Not a Diagnosis

Cortisol has become the most monetised hormone on the internet — blamed for belly fat, exhaustion, poor sleep and almost everything else, and used to sell supplements, saliva tests and “adrenal support” protocols.

Some of the underlying biology is real. Most of what is sold on the back of it is not.

What cortisol actually does

Cortisol is a hormone produced by the adrenal glands. It is not a villain — you cannot function without it.

It follows a daily rhythm: highest shortly after waking, falling through the day, lowest around midnight. That morning peak is what gets you out of bed. It regulates blood sugar, blood pressure, the immune response and the body's handling of stress.

Cortisol rises in response to stress, and that is the system working correctly, not malfunctioning.

“Adrenal fatigue” is not a recognised condition

This needs saying plainly, because a great deal of money changes hands over it.

The theory holds that prolonged stress “exhausts” the adrenal glands so they stop producing enough cortisol, causing fatigue, brain fog and low mood.

It is not recognised by the Society for Endocrinology, by NICE, or by any endocrine society internationally. Systematic reviews have looked for evidence of it and found none — the studies claiming to demonstrate it use inconsistent definitions and unvalidated tests.

Salivary cortisol profiling, sold widely to diagnose it, has no validated role in assessing everyday stress or tiredness. We do not arrange these tests.

This matters for two reasons. First, people spend substantial sums on supplements and protocols for a condition that does not exist. Second — and more importantly — the symptoms attributed to “adrenal fatigue” are real, and they usually have a real cause that goes unexamined while the money is spent elsewhere.

What those symptoms usually turn out to be

Persistent fatigue, poor concentration and low mood are genuinely common, and the causes are unglamorous but treatable:

• Iron deficiency — and ferritin has to be asked for specifically, since a normal full blood count does not exclude it
• Sleep apnoea — substantially under-diagnosed, particularly in women
• Thyroid disease
• Depression and anxiety, which present physically far more often than people expect
• B12 deficiency, coeliac disease, and diabetes
• Alcohol, medication, and simply not sleeping enough

A focused set of blood tests answers most of this, and costs a great deal less than a year of supplements.

The genuine adrenal conditions — which are rare but real

Addison's disease is genuine adrenal insufficiency. It is uncommon, and it is serious — causing profound fatigue, weight loss, low blood pressure, salt craving and skin darkening. It is diagnosed with a specific blood test, not a saliva panel, and it needs lifelong treatment.

Cushing's syndrome is genuine cortisol excess — causing weight gain around the trunk with thin limbs, a rounded face, purple stretch marks, easy bruising, muscle weakness and high blood pressure.

Both are real, both are testable, and neither resembles the vague picture sold as “adrenal fatigue”. If your symptoms genuinely fit either, that warrants proper endocrine assessment — which is free on the NHS.

What actually lowers cortisol

The interventions with real evidence are free, and unsurprising:

Sleep

Sleep deprivation raises evening cortisol, and poor sleep is both a cause and a consequence of stress. Fixing sleep does more than any supplement — and for persistent insomnia, CBT for insomnia is first-line and available free on the NHS.

Exercise — with a caveat

Regular moderate activity lowers baseline stress hormones over time. Note the words “over time”: a hard session acutely raises cortisol, which is normal and beneficial. Chronic overtraining without recovery does raise it persistently, which is worth knowing if you are training hard and feeling worse.

Psychological approaches

CBT, mindfulness-based stress reduction and structured relaxation all have measurable effects, and NHS Talking Therapies takes self-referrals without a GP appointment.

Alcohol and caffeine

Both raise cortisol. Alcohol also fragments sleep, which compounds the effect. Caffeine late in the day is worth moving earlier.

Actually addressing the stressor

The least marketable intervention and often the most effective. Where the source is work, adjustments — hours, workload, role — do more than anything taken by mouth. That is also something a letter to an employer can support.

What does not work

• Adrenal support supplements and glandular extracts — no good evidence, and some contain actual steroid hormones, which is a genuine safety concern
• Ashwagandha and other adaptogens — some small studies suggest modest effects on subjective stress; the evidence is weak, quality control is variable, and there have been reports of liver injury
• Salivary cortisol panels — no validated role outside specific endocrine investigation
• “Cortisol-blocking” fat loss products — no

The honest summary

Cortisol is real, adrenal fatigue is not, and the symptoms people attribute to it deserve a proper explanation rather than a supplement.

If you are persistently exhausted, the useful next step is a focused set of blood tests and an honest conversation about sleep, mood, alcohol and workload — not a saliva kit.

That is a conversation we are happy to have, including telling you when the answer is that nothing is medically wrong and the problem is your working week.