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Why You Shouldn’t Bother With an Adrenal Fatigue Test

Written by Dr. Michael Ruscio, DC on February 3, 2021

Written by Dr. Michael Ruscio, DC on February 3, 2021 — Reviewed by Mike T. Nelson

• What Is Adrenal Fatigue?|
• Symptoms|
• Testing|
• Fatigue Causes|
• Improve Fatigue|
• Herbs|
• Vitamins and Minerals|
• Diet|
• Support Microbiome|
• Sleep|
• Stress Reduction|
• Verdict|

Adrenal fatigue tests are popular in functional and integrative medicine. However, there is no clear evidence for the adrenal fatigue theory, and adrenal fatigue tests don’t help you understand what is causing your fatigue.

Let’s explore the theory of adrenal fatigue, what adrenal fatigue test results mean, and simple steps you can take to resolve your fatigue.

What Is Adrenal Fatigue?

Your adrenal glands are small but mighty parts of your endocrine system. They help create the stress hormones cortisol, adrenaline, and aldosterone [1], as well as small amounts of progesterone [2]. These adrenal hormones also help regulate your immune system.

It’s been hypothesized that chronic stress can “fatigue” your adrenal glands, leading to impaired adrenal function, persistent low levels of cortisol, immune system imbalance, and fatigue. 

The alleged symptoms commonly associated with adrenal fatigue include:

• Low blood pressure
• Chronic fatigue or ongoing tiredness
• Lightheadedness
• Low sex drive
• Low immune system function (frequent colds or illnesses)
• Hormone imbalances

However, many other health conditions, including gut dysbiosis, thyroid imbalances, or autoimmune conditions can cause these signs and symptoms. Despite this hypothesis of “adrenal fatigue”, there is no evidence that it exists as a medical condition [3]. 

Adrenal fatigue is distinct from recognized adrenal gland dysfunctions such as Addison’s disease (very low cortisol, also called “adrenal insufficiency”) and Cushing syndrome (very high cortisol), which are both medical conditions requiring the help of a health care provider.

​Adrenal Fatigue Testing

When patients present with fatigue symptoms, many functional doctors and naturopaths use salivary cortisol tests to diagnose “adrenal fatigue.”

To complete the adrenal fatigue test, a patient collects saliva samples, typically at four times during the day:

• On waking
• At noon
• Around 4:00 pm
• At bedtime

The saliva test measures your levels of cortisol, commonly known as the stress hormone. Multiple samples are collected because your cortisol levels are naturally different in the morning, afternoon, and night.

Your cortisol test results are shown as a curve that represents your free cortisol levels throughout the day. The curve is compared to a normal range.

According to the adrenal fatigue theory, low cortisol production correlates with fatigue symptoms, while high cortisol correlates with elevated stress, feeling wired, insomnia, and anxiety.

Is Adrenal Fatigue Testing Useful?

Despite the popularity of this theory, there is no evidence that adrenal fatigue is an actual condition, nor that adrenal fatigue testing results correlate with fatigue symptoms. The Endocrine Society does not recognize adrenal fatigue as a real condition [3].

A systematic review of 58 studies about adrenal fatigue and cortisol testing was completed in 2016 [3]. The study authors concluded that:

• Cortisol levels aren’t closely associated with fatigue symptoms 50-80% of the time, no matter the testing method used.
• Salivary cortisol testing is not an accurate way to assess your adrenal glands’ function.
• Popular questionnaires of “adrenal fatigue symptoms” are not scientifically validated.
• There is no evidence that “adrenal fatigue” exists as a medical condition or is a cause of ongoing fatigue.

A separate systematic review of 108 studies concluded that people with post-traumatic stress disorder (PTSD) (a condition characterized by chronically elevated stress) had cortisol levels and patterns similar to those of healthy individuals [4]. An additional systematic review and meta-analysis found that neither adulthood trauma nor PTSD was associated with variations in cortisol levels [5]. These results suggest the adrenal fatigue hypothesis, that stress affects your adrenal function and cortisol levels, is not real.

In other words, adrenal fatigue tests don’t give you any useful clinical information and don’t correlate with symptoms. If you’re fatigued, your money is probably better spent on investigating and repairing the root causes of your symptoms rather than on testing that doesn’t give you any actionable information.

If Adrenal Fatigue Isn’t Real, What’s Causing My Fatigue?

Even though adrenal fatigue test results aren’t reliable, your fatigue is a very real, frustrating experience you want to resolve. There are several likely reasons for ongoing fatigue, many of which are easily addressed.

Gut Health Imbalances 

One of the most common reasons for fatigue is an overlooked and unaddressed problem in the gut. For example, research shows that fatigue is a very common symptom for people with IBS [6, 7], IBD [8], leaky gut [9, 10], and non-celiac gluten sensitivity [11]. It’s also quite common for people with an underactive thyroid (hypothyroidism) [12], which also frequently improves with gut support [13, 14, 3].

Thyroid Trouble

Low levels of thyroid hormones can cause fatigue [12]. Your doctor can order a simple blood test for Thyroid Stimulating Hormone (TSH) and free T4 thyroid hormone. Low free T4 indicates hypothyroidism (underactive thyroid) when paired with high TSH. 

Nutrient Deficiencies 

Specific nutrient deficiencies can contribute to fatigue, notably iron deficiency (anemia) [15] or deficiency of several B vitamins [16, 17] and vitamin C [18, 19]. 

Ongoing Stress Levels

Even though stress and elevated cortisol doesn’t cause adrenal fatigue, high levels of perceived stress — stress from the realities of your daily life like your job, marriage, finances, etc. — can lead to fatigue. This is likely because stress does impact your memory and learning, digestion, cardiovascular health, sleep, immune function, and hormones [20]. The most famous example is getting a stomach ache when you’re nervous about something, like a job interview or a performance.

Sleep Problems

Of course, sleep problems, including insomnia, sleep apnea [3], and too little sleep can also affect your energy levels.

Chronic Pain 

Chronic pain due to injuries or autoimmune health conditions, such as rheumatoid arthritis [21] or fibromyalgia [22], can cause fatigue.

Simple Steps To Improve Fatigue Symptoms

Even if adrenal fatigue isn’t considered a real medical condition, fatigue symptoms are real. The good news is there is plenty you can do to improve them.

Balance Your Gut Microbiome

Though it may not seem like your gut has anything to do with your fatigue symptoms, fatigue is closely correlated with gut imbalances like IBS [6, 7] and leaky gut [9, 10]. 

Probiotics and gut-healing diets can help recondition your gut environment by crowding out bad bacteria, reducing inflammation, and improving leaky gut [23, 24, 25, 26]. 

Probiotics were shown in a meta-analysis to improve depression, which often includes fatigue symptoms [27], and may also help reduce cortisol and anxiety in humans [28]. For best results, use three high-quality probiotic products together. For more information about how to use probiotics, see my Probiotics Starter Guide.

And gut healing diets like the low FODMAP diet have been shown to reduce fatigue [29, 30] because they reduce the food source for the bad bacteria that may be triggering your symptoms.

If you don’t notice the improvement you’d like to see from diet and probiotics, you may need to consider using antimicrobial herbs or medication to clear gut dysbiosis. The protocol in my book, Healthy Gut, Healthy You, gives detailed instructions on how to use these tools. You might also benefit from reaching out to our clinic to learn about becoming a patient.

Eat for Blood Sugar Balance

Eating to keep blood sugar balanced reduces blood sugar swings and hypoglycemia, which can lead to fatigue. 

A low-glucose (low carb) diet rich in high-quality protein, ample healthy fats, and adequate fiber from fruits and vegetables can help. The easiest way to do this is to eat a real-food diet that is low in processed foods, like the paleo diet. The low FODMAP diet is another option that has been shown to improve fatigue [31]. If you need help creating the right diet for yourself, consider reaching out to our clinic to meet with our health coach.

Herbs to Balance Your Stress Response

Certain herbs can help your body adapt to the demands of stress. This class of herbs is called adaptogens, which means they help your body adapt to stress. Several of these herbs have been studied for their impact on fatigue and chronic stress. 

Rhodiola (Rhodiola rosea) and Ginseng (Panax ginseng) have the best evidence supporting their ability to reduce fatigue, stress, exhaustion, and to improve concentration and mood [32, 33, 34, 35, 36, 37]. 

Eleuthero (Eleutherococcus senticosus) and Ashwagandha (Withania somnifera) also have some limited evidence to suggest they help reduce fatigue [38]. These herbs are generally available at health food stores or online retailers as capsules, tinctures, or extracts.

Vitamins and Minerals for Adrenal Support

Deficiencies of a few particular vitamins and minerals are correlated with fatigue symptoms. Iron deficiency anemia can definitely cause fatigue [15]. Consider supplementing with iron. However, excess iron can cause side effects, so ask your doctor to assess your iron and ferritin levels to make sure iron supplementation is right for you.

Using supplemental B vitamin complex has been shown to reduce stress and stress perception [16, 17], and vitamin C may also improve your fatigue [18, 19].

Get Enough Sleep

It may seem obvious, but getting enough sleep can help with fatigue. If you have health conditions like sleep apnea or others that are affecting your ability to sleep well, get help.

Stress Relief

Managing your stress levels can help keep your blood sugar balanced and promote your energy levels and a healthy and happy mood. If you feel chronically stressed, find regular ways to manage this stress. Consider lifestyle practices like exercise, yoga, meditation, therapy, and time in nature. 

Diet, Lifestyle, and Better Gut Health, Not Adrenal Fatigue Tests, Can Improve Fatigue

Salivary adrenal fatigue tests don’t give you actionable information because they don’t help you understand the source of your fatigue, and don’t accurately reflect your adrenal gland status.

Your health care dollars are better spent supporting your gut health and energy levels with adaptogenic herbs, correcting any egregious nutrient deficiencies, a blood-sugar balancing diet, probiotic supplements, and addressing your sleep and stress levels. 

Fatigue often improves by attending to your basic health, so start there. With care and attention, you’ll see your energy levels improve so you can get back to enjoying your life.