by Dr. Joseph Mercola, Mercola:
Story at-a-glance
- CYP19A1, a gene encoding aromatase that converts testosterone to estradiol, has also been linked to COVID-19 severity. A mutation in this gene, which increases aromatase activity, is found in 68.7% of men hospitalized with COVID-19
- Short pinky fingers are associated with lower testosterone levels. A July 2024 study published in Andrology confirmed that COVID-19 patients who had shorter pinky fingers — indicative of lower testosterone levels — experienced more severe outcomes
TRUTH LIVES on at https://sgtreport.tv/
- Testosterone production declines with age, starting around age 30. Other factors like chronic diseases, stress, poor diet and environmental factors also contribute to reduced testosterone levels. Symptoms of low testosterone include fatigue, irritability, reduced libido, infertility and changes in body composition
- Niacinamide naturally increases your testosterone levels by raising NAD+. Studies show it’s helpful for addressing age-related testosterone decline in both males and females
- Additional strategies to boost your testosterone include regular exercise, adequate sun exposure to optimize vitamin D levels and herbal remedies like fenugreek and ashwagandha
Testosterone, also known as the male sex hormone, is important for the health of both genders. This steroid hormone is primarily produced in men’s testicles and, to a lesser extent, in women’s ovaries. It’s responsible for the development of male secondary sexual characteristics, muscle mass and strength, bone density and the production of red blood cells.1
It also influences mood, energy levels and cognitive function in both sexes.2 However, testosterone levels in men naturally decline with age. Previous research3,4 suggested that this decline in testosterone affects elderly men’s risk of severe COVID-19.
To further investigate the link between testosterone levels and COVID-19 severity, a study published in July 2024 in the journal Andrology5 examined testosterone-dependent finger length patterns in hospitalized COVID-19 patients compared to a control group. Their findings uncovered important insights about testosterone’s protective role against severe COVID-19 outcomes.
Further Proof of Testosterone’s Role in COVID Severity
The featured study,6 conducted at the Medical University of Lodz in Poland, examined two competing theories regarding testosterone’s impact on COVID-19 prognosis. The first, known as the high-androgen-driven theory, suggests that elevated testosterone levels cause the virus to infect cells more effectively.
Conversely, the second theory purports that lower testosterone levels, particularly common in elderly men, heighten their immune response to COVID-19, resulting in worse outcomes. To investigate these theories, the researchers analyzed finger length ratios — specifically comparing the index and little fingers — in hospitalized COVID-19 patients versus healthy controls.
This approach is based on the theory that digit ratios are influenced by exposure to testosterone and estrogen during fetal development and puberty. Longer index fingers are associated with low testosterone/high estrogen exposure, while longer little or pinkie fingers indicate high testosterone/low estrogen exposure.
Their findings showed that hospitalized COVID-19 patients consistently had shorter little fingers relative to their other fingers when compared to the control group, a “feminized” pattern indicative of lower testosterone levels. This supports the low-androgen-driven theory, which suggests that reduced testosterone contributes to more severe COVID-19 outcomes.
The lead researcher, Professor John Manning from Swansea University’s Applied Sports, Technology, Exercise and Medicine (A-STEM) research team, explained:7
“The patients had digit ratios that indicated low testosterone before and after birth. The pattern was present at the beginning of the pandemic and after widespread vaccination. This means we can conclude that testosterone is protective against severe COVID-19. The effect may arise because the hormone reduces inflammation in the lungs and other organs. The findings have public health and treatment implications.”
A Key Gene in Testosterone Metabolism Affects COVID Severity
In an earlier study published in Cell Reports Medicine,8 researchers uncovered another testosterone-related factor affecting COVID-19 severity in men — a gene called CYP19A1. The study, led by Gülsah Gabriel from the Leibniz Institute of Virology, builds on a decade of work investigating similar patterns in avian influenza.
CYP19A1 encodes aromatase, an enzyme that converts testosterone to estradiol. The researchers found that a specific mutation in this gene is present in 68.7% of men hospitalized with COVID-19, despite being rare in the general population. This mutation is known to increase aromatase activity, leading to lower testosterone and higher estradiol levels.
Moreover, the researchers found that SARS-CoV-2 infection itself dramatically increases aromatase expression in lung cells, far more than other respiratory viruses. These findings were corroborated through various methods, including analysis of human COVID-19 patients, examination of lung tissue from deceased patients, and experiments with golden hamsters.
In infected male hamsters, CYP19A1 expression increased significantly in the lungs, resulting in decreased testosterone and elevated estradiol levels in their plasma. This hormonal imbalance appears to contribute to more severe COVID-19 outcomes in males.
Interestingly, the researchers found that treating infected male hamsters with letrozole, an aromatase inhibitor, partially restored hormonal balance and improved lung health. These findings not only offer insights into why men face higher risks from COVID-19 but also highlight the often-overlooked role of hormones in respiratory infections.
As Gabriel notes, “It is one of the first studies [showing] that the lung, which is not a classical or typical endocrine organ, suddenly can become an endocrine organ upon infection. It seems that [respiratory viruses] can have long-lasting effects if they dysregulate the enzymes.”9
