Emerging research reveals that endocrine dysfunction may be one of the most significant and lingering legacies of COVID-19
When we first learned about COVID-19, we thought it was primarily a respiratory disease. The telltale signs—cough, shortness of breath, loss of smell—all pointed to the lungs as ground zero. But as the pandemic evolved, doctors and researchers began noticing something puzzling: recovered patients were reporting persistent symptoms that didn't fit the respiratory mold.
COVID-19 was initially classified as a respiratory illness with symptoms primarily affecting the lungs and airways.
Persistent symptoms like fatigue, mental fog, and mood swings pointed toward systemic effects beyond the respiratory system.
To understand how COVID-19 disrupts our hormones, we need to look at how the virus enters our cells. SARS-CoV-2 gains entry through a specific "lock" on the surface of our cells—a protein called ACE2 (Angiotensin-Converting Enzyme 2) 3 4 .
Think of ACE2 receptors as doors that the virus picks with its spike protein key. The problem for our endocrine system? These "doors" are widespread throughout hormonal glands, including the thyroid, pancreas, adrenal glands, pituitary, and testes or ovaries 3 .
ACE2 receptors are found in various endocrine tissues, enabling viral entry 3
Inflammation-induced blood clotting can compromise blood flow to endocrine glands, starving them of oxygen 7 .
A compelling 2025 study published in the Indian Journal of Endocrinology and Metabolism provides some of the most comprehensive evidence to date 1 .
Researchers recruited 83 patients who had recovered from COVID-19, 8-20 weeks after their recovery. The cohort included both mild cases and moderate-to-severe cases.
Comprehensive evaluation of thyroid, adrenal, gonadal, and prolactin systems 1
The results were striking. A full 53% of recovered COVID-19 patients showed some form of endocrine dysfunction more than three months after recovery 1 .
| Endocrine Dysfunction | Prevalence | Key Findings |
|---|---|---|
| Any Endocrine Abnormality | 53% (44/83 patients) | Affected more than half of studied patients |
| Pituitary Axis Alterations | 33.7% (28/83 patients) | Central control system disruption |
| Prolactin Level Abnormalities | 20.4% | Most common pituitary disturbance |
| Thyroid Function Abnormalities | 30.1% (25/83 patients) | Various forms of dysfunction |
| Male Gonadal Dysfunction | 14% of male patients | Low testosterone levels |
| Female Gonadal Dysfunction | 6% of reproductive-aged women | Menstrual irregularities |
Data from Indian Journal of Endocrinology and Metabolism, 2025 1
Over half of recovered patients showed endocrine abnormalities 1
What does it take to investigate the relationship between COVID-19 and endocrine dysfunction? Here's a look at the key research tools and methods that scientists use:
| Tool/Method | Function/Application | Example in COVID-19 Research |
|---|---|---|
| ACTH-Stimulation Test | Assess adrenal reserve and function | Identifying adrenal insufficiency in recovered patients 1 |
| Chemiluminescent Assay (CLIA) | Precise measurement of hormone levels | Quantifying TSH, cortisol, testosterone in patient samples 1 |
| Plasma Proteomics | Simultaneous analysis of thousands of proteins | Identifying protein patterns in mild vs. severe COVID-19 7 |
| ACE2 Receptor Mapping | Locating viral entry points in tissues | Demonstrating ACE2 presence in endocrine glands 3 |
| Cytokine Profiling | Measuring inflammatory molecules | Linking "cytokine storm" to endocrine tissue damage 7 |
Advanced techniques like Olink targeted proteomics have enabled researchers to analyze 3,072 proteins simultaneously in COVID-19 patients, revealing distinct protein signatures in mild versus severe cases 7 .
This comprehensive profiling helps identify specific pathways disrupted by the virus, including those involved in calcium signaling and growth factor response—both crucial for normal endocrine function.
| Hormone | Function | COVID-19 Impact |
|---|---|---|
| Cortisol | Stress response, metabolism | Adrenal insufficiency |
| TSH | Regulates thyroid function | Various thyroid disorders |
| Prolactin | Milk production, reproduction | Elevated or decreased levels |
| Testosterone | Sexual function, muscle mass | Low levels (hypogonadism) |
The discovery that over half of recovered COVID-19 patients show endocrine abnormalities has profound implications for long-term healthcare strategies 1 .
Endocrine disruptions don't always announce themselves with dramatic symptoms—they often manifest as lingering fatigue, weight changes, mood disturbances, and reduced quality of life—symptoms frequently reported in "long COVID" patients 4 .
Common long COVID symptoms that may relate to endocrine disruption 4
Making matters more complex, recent research suggests that environmental chemicals known as endocrine disruptors may amplify COVID-19 severity 2 .
Chemicals like bisphenol A (BPA), phthalates, and perfluorinated substances (PFAS)—found in plastics, food containers, and various consumer products—can interfere with hormonal signaling.
A 2020 systems biology study found that these endocrine-disrupting chemicals affect many of the same biological pathways that contribute to severe COVID-19, particularly those involved in immune response and inflammation 2 . This suggests that people with high exposure to these chemicals might be more vulnerable to COVID-19's endocrine effects—a concerning intersection of environmental and infectious disease threats.
The discovery that SARS-CoV-2 significantly disrupts our endocrine system represents a paradigm shift in how we understand and treat COVID-19.
No longer can we view it as solely a respiratory disease; we must recognize its potential to cause lasting hormonal havoc that extends far beyond the initial infection.
This new understanding brings both challenges and opportunities:
If you're experiencing persistent fatigue, unexplained weight changes, or other potential symptoms of hormonal imbalance after COVID-19, consider discussing endocrine testing with your healthcare provider.
Early detection and management of hormonal disorders can significantly improve recovery outcomes and quality of life.
By recognizing and addressing the "endocrine flaws" exposed by this pandemic, we can work toward more complete healing for the millions affected by this complex and still-unfolding disease.