If you’ve ever felt constantly exhausted, foggy, “wired-but-tired”, or low in mood, chances are you’ve come across the term “adrenal fatigue.” It’s a widely talked about concept in wellness spaces — offering a seemingly simple explanation for chronic stress-related symptoms: the idea that your adrenal glands have “burned out” from overwork.

But while the symptoms are very real and deserve attention, the theory itself isn’t supported by endocrinology research — and “adrenal fatigue” is not a recognised recognised diagnosis in conventional medicine.

In this article, we explore where the theory came from, what the science actually shows, and how to better understand what might really be causing your symptoms.

What Are the Adrenal Glands — and What Do They Actually Do?

Your adrenal glands are two small glands that sit on top of your kidneys. They play a central role in how your body responds to stress and help regulate essential functions through hormone production, including:

• Cortisol: Involved in metabolism, blood pressure regulation, inflammation, and the body’s stress response
• Aldosterone: Regulates salt and water balance to help control blood pressure
• Adrenaline & Noradrenaline: Involved in the body’s “fight or flight” response in high-stress situations

These hormones are regulated by a finely tuned system called the hypothalamic-pituitary-adrenal (HPA) axis, which responds dynamically to your body’s needs — not just stress levels.

Where Did the “Adrenal Fatigue” Theory Come From?

The term “adrenal fatigue” was first introduced in the late 1990s by a chiropractor who proposed that prolonged stress could gradually wear out the adrenal glands, leading to a state of low cortisol and non-specific symptoms such as:

• Persistent fatigue
• Difficulty getting up in the morning
• Brain fog
• Salt cravings
• Low mood or anxiety
• Poor stress tolerance

According to this theory, the adrenal glands become overworked and unable to keep up with the body’s demands.

While this concept gained traction in alternative health circles, it oversimplifies how the HPA axis works — and doesn’t align with what we see in scientific or clinical practice.

What the Research Says About Adrenal Fatigue

Over the past two decades, numerous studies have investigated whether adrenal fatigue is a measurable or medically valid condition. The results are consistent: there’s no reliable evidence that chronic stress causes adrenal glands to “burn out” or stop working properly in the way this theory suggests.

Key findings include:

✅ Normal Hormone Test Results

People diagnosed with adrenal fatigue typically have normal cortisol levels when tested using standard, validated methods used by internationally accredited laboratories, such as:

• Morning serum cortisol
• ACTH stimulation tests
• 24-hour urinary cortisol

These tests are clinically validated and widely used by endocrinologists to assess adrenal function. In contrast, some alternative testing methods — such as certain types of salivary or dried urine panels — are not standardised for medical diagnosis and may lead to inconsistent or misleading results. See our separate article on these tests here

🧪 No Agreed Diagnostic Criteria

Unlike recognised adrenal disorders like Addison’s disease (underactive adrenal glands) or Cushing’s syndrome (excess cortisol production), adrenal fatigue has no defined clinical markers, diagnostic standards, or consistent lab findings.

📣 Official Medical Stance

Leading expert bodies — including the Endocrine Society — have publicly stated that adrenal fatigue is not a recognized medical diagnosis. They caution against the use of unvalidated saliva testing, and against cortisol /adrenal steroid supplements unless true adrenal disease is diagnosed.

So What’s Really Causing These Symptoms?

Just because adrenal fatigue isn’t a valid diagnosis doesn’t mean your symptoms aren’t real. On the contrary — they’re common and important to address.

Fatigue, brain fog, poor sleep, and low resilience to stress can be caused by a number of conditions, including:

• Sleep disorders like insomnia or sleep apnoea
• Mental health conditions like depression or anxiety
• Hormonal issues such as hypothyroidism, perimenopause/menopause, and if in a cyclical pattern could be PMS/Premenstrual Dysphoric Diorder
• Nutrient deficiencies, including iron, B12, or vitamin D
• Post-viral fatigue or chronic infections
• Chronic stress or burnout  — without adrenal gland failure

In many cases, the issue isn’t with the adrenal glands themselves, but with how the body is processing stress, recovering, and regulating energy across multiple systems.

How We Approach It at ERH Associates

At ERH, when we see patients who’ve been told they have “adrenal fatigue” — or who feel dismissed when blood tests come back “normal.” Our approach is to go deeper.

We consider or aim for:

• Hormone blood testing where appropriate
• A systems-based review of energy, sleep, thyroid function, mental health, pattern/triggers for symptoms and lifestyle factors
• Evidence-based lifestyle strategies for nervous system recovery, burnout, and fatigue
• Clarity without resorting to unsupported labels

Sometimes the issue is endocrine. Sometimes it’s nervous system dysregulation. Sometimes it’s both. Either way, you deserve answers grounded in science and care.

Final Thoughts

“Adrenal fatigue” has become a popular explanation for stress-related symptoms — but it’s not scientifically accurate, and it doesn’t help guide effective treatment. Most people diagnosed with adrenal fatigue have normal adrenal function, and pursuing this label can delay proper investigation into the real underlying causes. If you’re feeling burnt out, low in energy, or unable to recover from stress, there is a path forward — it just might start with a different diagnosis

Feeling burnt out or run down?

We’re currently developing our Burnout Reset Program — designed to support recovery from stress, fatigue, and nervous system overload using evidence-based strategies.

Watch this space — the program will be launching soon.
In the meantime, you can  sign up to our newsletter below or follow us on social media for updates and early access.