What is Chronic Fatigue?

At Sheen Vein (Aesthetics and Functional Medicine) in St. Louis, many patients come to us saying: “I’m just tired all the time, and no one can tell me why.” Often, they’ve already seen multiple doctors, had basic labs, and been told, “Everything looks normal.” Yet, they wake up exhausted, struggle to get through the day, and feel as if their body just won’t cooperate.

This is the reality of chronic fatigue, a complex condition that is more than simply being tired. It can have deep physiological roots, and when left unaddressed, it severely impacts quality of life. In this article, we’ll explore what chronic fatigue is, how it differs from ordinary tiredness, what causes it, and how a functional medicine approach offers real solutions.

What is Chronic Fatigue?

Chronic fatigue is a persistent, overwhelming exhaustion that does not improve with rest and lasts for months or even years. Unlike normal tiredness—which typically follows exertion and improves with sleep—chronic fatigue is disabling and often accompanied by other symptoms such as brain fog, muscle aches, and poor concentration.

In some cases, chronic fatigue meets the criteria for Chronic Fatigue Syndrome (CFS), also called Myalgic Encephalomyelitis (ME), a recognized medical condition characterized by:

Severe fatigue lasting 6 months or longer
Post-exertional malaise (worsening of symptoms after physical or mental effort)
Unrefreshing sleep
Cognitive difficulties (“brain fog”)
Sometimes pain, headaches, sore throat, or swollen lymph nodes

But even if someone does not meet the strict criteria for ME/CFS, they may still suffer from functional chronic fatigue—a state of energy depletion driven by metabolic, hormonal, immune, or mitochondrial dysfunction.

Symptoms of Chronic Fatigue

Chronic fatigue manifests in different ways, but the most common symptoms include:

Persistent exhaustion not relieved by rest
Brain fog – difficulty focusing, memory issues, or slowed thinking
Unrefreshing sleep – waking up tired even after 8+ hours
Muscle weakness or aches
Headaches
Dizziness or lightheadedness (sometimes related to low blood pressure or poor circulation)
Mood changes such as anxiety or depression
Increased susceptibility to infections or slower recovery from illness

Some patients describe it as “like having the flu that never goes away.”

Who Gets Chronic Fatigue?

Chronic fatigue can affect anyone, though women are diagnosed more often than men. It often develops in people in their 30s to 50s, but younger adults and even teenagers can experience it.

In our St. Louis clinic, we see patients across the spectrum—busy professionals, parents, and retirees—whose lives have been disrupted by unrelenting fatigue.

What Causes Chronic Fatigue?

There is no single cause of chronic fatigue. Instead, it usually arises from multiple overlapping factors that deplete the body’s energy systems. Some of the most common contributors include:

1. Mitochondrial Dysfunction

The mitochondria are the “powerhouses” of our cells, producing ATP (energy). If they are damaged by toxins, infections, or oxidative stress, energy output plummets.

2. Chronic Infections

Viruses like Epstein-Barr, Lyme disease, and even long COVID can trigger or worsen chronic fatigue by overactivating the immune system.

3. Hormonal Imbalances

Low thyroid function
Adrenal fatigue or cortisol dysregulation
Imbalances in sex hormones (estrogen, testosterone, progesterone)

All can lead to poor energy regulation.

4. Sleep Disorders

Sleep apnea, restless leg syndrome, or poor sleep quality prevent the body from restoring itself at night.

5. Nutrient Deficiencies

Low levels of vitamin D, magnesium, B vitamins, iron, and CoQ10 are common in patients with fatigue.

6. Gut Health Imbalances

Leaky gut, dysbiosis, or food sensitivities trigger inflammation, which drains energy and affects neurotransmitter production.

7. Stress and Trauma

Chronic stress elevates cortisol and dysregulates the hypothalamic-pituitary-adrenal (HPA) axis, a central player in energy balance.

8. Environmental Toxins

Mold exposure, heavy metals, and other toxins can impair mitochondrial function and immune regulation.

Conventional Medicine and Chronic Fatigue

Traditionally, conventional medicine struggles with chronic fatigue because routine labs often look “normal.” Patients are sometimes misdiagnosed with depression or told it’s “all in their head.”

Treatment often focuses on symptom relief with:

Sleep medications
Antidepressants
Pain relievers
Physical therapy

While these may help somewhat, they rarely address the root causes.

A Functional Medicine Approach to Chronic Fatigue

At Sheen Vein (Aesthetics and Functional Medicine), we take a deeper look. Chronic fatigue is not a random condition—it’s the body’s way of signaling an underlying imbalance. By identifying and correcting these imbalances, many patients can regain energy and vitality.

Step 1: Comprehensive Evaluation

We start with a detailed history and advanced testing, which may include:

Thyroid panel (TSH, free T3, free T4, antibodies)
Adrenal cortisol rhythm testing
Mitochondrial markers (CoQ10, carnitine)
Nutrient panels (iron, B vitamins, magnesium, vitamin D)
Inflammation markers (CRP, homocysteine)
Gut testing for dysbiosis, leaky gut, or infections
Viral panels if chronic infection is suspected

Step 2: Restoring Mitochondrial Health

We support energy production with nutrients like:

CoQ10
Magnesium
B vitamins
L-carnitine
Alpha-lipoic acid

These compounds fuel the mitochondria and improve ATP production.

Step 3: Balancing Hormones

If thyroid, adrenal, or sex hormones are imbalanced, we use targeted therapies to restore normal rhythms—sometimes with natural supplementation, other times with bioidentical hormone therapy.

Step 4: Optimizing Gut Health

Through stool testing and dietary adjustments, we correct imbalances, eliminate trigger foods, and restore the gut microbiome. This reduces inflammation and improves nutrient absorption.

Step 5: Lifestyle Interventions

Sleep optimization – addressing apnea, sleep hygiene, and circadian rhythm
Gentle exercise – pacing activity to avoid post-exertional crashes
Stress reduction – mindfulness, breathwork, and restorative practices like yoga

Step 6: Advanced Therapies

We also offer cutting-edge therapies to support recovery:

IV nutrient therapy for rapid replenishment
Red light therapy (PBM) to stimulate mitochondrial repair
PRF and regenerative medicine for localized pain relief that worsens fatigue
PEMF therapy to improve circulation and cellular energy

Living with Chronic Fatigue

One of the most important lessons for patients is learning how to pace themselves. Overexertion can worsen fatigue, so balancing activity with rest is key. Patients also benefit from supportive communities, counseling, and compassionate care that validates their experience.

The encouraging truth is that chronic fatigue does not have to be a life sentence. By addressing the root drivers, patients often experience dramatic improvements in energy, mood, and daily function.

Final Thoughts

Chronic fatigue is more than just being tired—it’s a sign that the body’s energy systems are under strain. Conventional medicine often overlooks it, but functional medicine provides a path forward by identifying and correcting the underlying causes.

At Sheen Vein (Aesthetics and Functional Medicine) in St. Louis, we specialize in helping patients uncover the root reasons for their fatigue and restoring energy through personalized, integrative care.

If you’ve been struggling with unrelenting fatigue and have been told “your labs look normal,” don’t give up. Schedule a consultation with us today through our contact page. Together, we can uncover the cause of your fatigue and help you reclaim your energy and your life.

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