Men's Testosterone Levels May Have Dropped by Over 50% in the Last 50 Years, New Study Finds
Meta Description: New research suggests men's testosterone levels have fallen by more than 50% since the 1970s. Learn about the possible causes, health impacts, and what experts recommend.
A growing body of scientific research indicates that testosterone levels in men may have declined dramatically over the past five decades. According to a recent analysis presented at the 2026 European Society of Human Reproduction and Embryology (ESHRE) conference, average testosterone levels among men have dropped by more than 50% compared with levels recorded in the early 1970s.
The findings have renewed concerns among researchers about male reproductive health and overall wellbeing. While testosterone is commonly associated with sexual health and fertility, it also plays an essential role in maintaining muscle strength, bone density, metabolism, mood, and energy levels.
Although the study has not yet undergone peer review, scientists believe the results add to increasing evidence that male reproductive health has been steadily declining worldwide.
What the New Research Found
Researchers analyzed data from six long-term studies conducted between 1972 and 2019. The review included testosterone measurements from nearly 118,600 men across five countries:
- United States
- Israel
- Brazil
- Finland
- Denmark
The analysis found a consistent decline in testosterone levels across every study included.
According to the researchers, testosterone levels measured in 2019 were, on average, more than 50% lower than those recorded in 1972. They also noted that the decline appears to have accelerated after the year 2000.
Overall, the average reduction since 1979 was estimated at approximately 54%, which equates to nearly a 1% decrease every year.
Scientists argue that such a consistent downward trend is unlikely to be explained by random statistical variation alone.
Why Testosterone Matters
Testosterone is the primary male sex hormone, but its functions extend well beyond reproduction.
Healthy testosterone levels help regulate:
- Sperm production
- Sexual desire (libido)
- Erectile function
- Muscle growth
- Bone strength
- Energy levels
- Mood
- Fat distribution
- Metabolism
- Cognitive performance
Low testosterone can affect physical, emotional, and reproductive health, especially when hormone levels decline below the normal range.
Possible Reasons Behind the Decline
Researchers believe there is no single explanation for the decrease in testosterone levels. Instead, several lifestyle, medical, and environmental factors may be working together.
1. Rising Obesity Rates
One of the strongest suspected contributors is obesity.
Excess body fat contains an enzyme called aromatase, which converts testosterone into estrogen. As body fat increases, testosterone production can decline naturally.
Obesity is also associated with chronic inflammation, another factor that may interfere with healthy hormone production.
2. Diabetes and Insulin Resistance
Type 2 diabetes and insulin resistance may also contribute to falling testosterone levels.
High blood sugar levels can affect the hypothalamus and pituitary gland, two parts of the brain responsible for controlling hormone production.
When communication between the brain and the testes is disrupted, testosterone production may decrease.
3. Environmental Chemicals
Scientists are also investigating the role of endocrine-disrupting chemicals.
These substances can interfere with the body's hormone systems and are found in some plastics, pesticides, industrial chemicals, and certain household products.
Particular attention has focused on PFAS, often called "forever chemicals," because they persist in the environment and the human body for long periods.
Although more research is needed, experts suspect that long-term exposure to these chemicals could influence hormone production.
4. Lifestyle Factors
Modern lifestyles may also contribute to lower testosterone levels.
Potential influences include:
- Poor diet
- Physical inactivity
- Chronic stress
- Lack of sleep
- Smoking
- Excessive alcohol consumption
Each of these factors has previously been linked to hormonal imbalance in varying degrees.
Link to the Male Fertility Crisis
The findings align with previous research showing that sperm counts have declined significantly over the last four decades.
Many scientists believe these trends may be connected because testosterone is essential for healthy sperm production.
Researchers involved in both studies argue that the decline in male reproductive health deserves greater public health attention.
However, experts caution that more research is needed before definitive conclusions can be drawn about the exact relationship between testosterone decline and fertility.
Should Men Take Testosterone Supplements?
Despite growing concern over declining testosterone levels, medical experts do not recommend testosterone therapy for everyone.
Testosterone replacement therapy can benefit men diagnosed with clinically low testosterone, but it should only be prescribed after proper medical evaluation.
Taking testosterone without medical supervision can reduce the body's natural hormone production.
External testosterone signals the brain that sufficient hormone is already available, which can suppress natural testosterone production and may even reduce sperm production.
For this reason, hormone therapy should always be discussed with a qualified healthcare provider.
How Men Can Support Healthy Testosterone Levels Naturally
Although aging naturally leads to a gradual decline in testosterone, lifestyle improvements may help support healthy hormone levels.
Experts commonly recommend:
- Maintaining a healthy body weight
- Exercising regularly, particularly resistance training
- Sleeping seven to nine hours each night
- Eating a balanced diet rich in protein, healthy fats, vitamins, and minerals
- Managing stress effectively
- Limiting excessive alcohol intake
- Avoiding smoking whenever possible
These habits also improve overall health, cardiovascular function, and metabolic wellbeing.
Limitations of the Research
While the findings are significant, it is important to recognize the study's limitations.
The research was presented at the 2026 European Society of Human Reproduction and Embryology (ESHRE) conference but has not yet been published in a peer-reviewed scientific journal.
Peer review allows independent experts to evaluate research methods, statistical analysis, and conclusions before publication.
As a result, the findings should be viewed as preliminary until the full study becomes available.
Final Thoughts
The latest research suggests that men's testosterone levels may have fallen substantially over the past five decades, adding to growing concerns about male reproductive health worldwide.
Researchers believe increasing obesity, diabetes, environmental chemical exposure, and lifestyle changes could all be contributing factors. While the findings are concerning, experts stress that additional peer-reviewed research is needed to better understand the causes and long-term consequences.
Rather than turning immediately to testosterone supplements, men experiencing symptoms of low testosterone should consult a healthcare professional for proper testing and personalized treatment recommendations. In many cases, maintaining a healthy lifestyle remains one of the most effective ways to support hormone health.
Sources
- European Society of Human Reproduction and Embryology (ESHRE) Congress 2026 Presentation: Temporal Trends in Total and Free Testosterone (1972–2019): A Systematic Review and Meta-Trend Analysis.
- Hebrew University-Hadassah Braun School of Public Health.
- The Independent. "Men's testosterone levels have fallen by half in last 50 years, scientists warn." Published July 10, 2026.
Disclaimer
This article is intended for informational and educational purposes only and should not be considered medical advice. The featured research had not been peer reviewed at the time it was presented. If you are experiencing symptoms of low testosterone or have concerns about your hormone health, consult a qualified healthcare professional for evaluation, diagnosis, and treatment recommendations.