Men's Testosterone Levels Have Fallen 54% Since 1972, New Study Links Decline to Obesity and Metabolic Health

What Did the New ESHRE Testosterone Study Find? Key Takeaways

• Men's average testosterone dropped 54% since 1972, and the decline sped up after 2000.

• Obesity and metabolic syndrome may explain a quarter to half of the drop.

• India's rising obesity and diabetes rates make this especially relevant here.

• Don't self-medicate with testosterone boosters. See a doctor for proper evaluation.

The average man today may produce less than half the testosterone his grandfather did at the same age, according to a large international analysis presented at the European Society of Human Reproduction and Embryology (ESHRE) 2026 Annual Meeting in London. Researchers say rising obesity, metabolic disease, and environmental changes may all be contributing to this testosterone decline, although the findings have not yet undergone peer review.

The findings have renewed scientific interest in the factors influencing male hormones and whether changing metabolic health and environmental exposures are affecting men's reproductive health across generations.

What Did the New ESHRE Testosterone Study Find?

According to a pooled analysis based on studies from multiple countries, a study led by Prof. Hagai Levine at the Hebrew University-Hadassah Braun School of Public Health in Israel found that average total testosterone levels declined by 54% between 1972 and 2019. It involved a pooled analysis of 12 longitudinal studies including data from approximately 102,000 adult men across seven countries.

All 12 studies showed the same overall trend of declining testosterone over time, leading researchers to conclude that the pattern is unlikely to be explained by chance alone. The rate of decline also accelerated after 2000.

Importantly, the researchers compared men of similar ages across different decades rather than simply observing the natural decline in testosterone that occurs with ageing. This means the reported 54% decline reflects generational differences in testosterone levels rather than the normal hormonal changes expected as men grow older.

Professor Hagai Levine stated that his findings provide evidence of a serious and under-recognized reproductive health challenge among men and explained why the issue extends beyond libido and fertility to overall male health. The findings were presented at the ESHRE 2026 Annual Meeting and have not yet undergone peer review.

Why Does Testosterone Matter?

Testosterone is the primary male sex hormone. It plays an important role in:

• Maintaining muscle mass and strength

• Supporting bone density

• Sperm production and male fertility

• Sex drive (libido)

• Mood and overall sense of wellbeing

• Red blood cell production

Low testosterone symptoms can include reduced libido, fatigue, erectile dysfunction, infertility, loss of muscle mass, reduced bone density, and low mood. However, these symptoms are not specific to low testosterone alone. A diagnosis of hypogonadism requires both compatible symptoms and consistently low testosterone levels confirmed by appropriate laboratory testing under medical supervision.

Why Are Testosterone Levels Declining in Men Worldwide?

No single cause has been confirmed. Researchers point to a combination of factors working together:

• Rising rates of obesity and metabolic syndrome

• Possible exposure to hormone-disrupting chemicals in everyday products

• Rising ambient heat

When asked to put a number on it, Prof. Levine offered what he called an educated guess to The Guardian that obesity and metabolic syndrome together might explain somewhere between a quarter and half of the overall decline.

Can Obesity and Diabetes Really Cause Low Testosterone?

Yes, excess body fat and insulin resistance can meaningfully lower testosterone, through more than one biological pathway at once.

MedBound Times reached out to Dr. Priyanka Bagdi, a fertility specialist, to explain the mechanism in plain terms.

In simple terms, fat tissue contains an enzyme called aromatase, which converts testosterone into estrogen, the primary female sex hormone. The more fat tissue a man carries, the more of this conversion happens, so less testosterone is left in circulation.

At the same time, obesity-related inflammation and insulin resistance interfere with the hormone signals the brain sends to the testes to keep testosterone production going.

Some scientists in the field think this metabolic link could account for even more of the decline than Levine's own estimate.

Do Plastics and Endocrine-Disrupting Chemicals Play a Role Too?

Possibly, but the evidence is still inconsistent and unproven.

Certain everyday chemicals, found in some plastics, pesticides, and flame retardants, are known as endocrine disruptors because they can mimic or interfere with the body's natural hormones.

Scientists have long suspected these substances might be part of the story behind declining testosterone and sperm counts, but studies looking directly at chemical exposure and hormone levels in people have produced mixed results so far.

Even so, it makes sense to reduce unnecessary exposure to these chemicals while scientists continue to investigate their long-term effects, rather than waiting for absolute proof.

Is Testosterone Decline a Bigger Risk for Men in India?

Based on metabolic health data from India itself, it can be seen that Indian men can be vulnerable to the same factors that are responsible for the worldwide testosterone decline.

The ICMR-INDIAB study conducted across the country showed a prevalence of diabetes of 11.4% and generalized obesity in 28.6% of Indians while almost 40% of people had abdominal obesity.¹

Currently, more than 100 million (10 crore) people in India are living with diabetes, highlighting the country's growing metabolic health burden.¹

The more recent 2025 ICMR-INDIAB study says: 43.3% of adult Indians are metabolically obese but non-obese, meaning that even though they do not suffer from excess weight, they are still exposed to the same factors responsible for the metabolic problems of obese individuals such as high blood glucose and cholesterol levels.² Thus, it is not necessary for a man to look obese to have the same hormonal pathway functioning against his testosterone production.

Should Men Take Testosterone Boosters to Raise Low Levels?

No, self-medicating with testosterone supplements or boosters without a diagnosis is discouraged, and may cause harmful effects. Dr. Bagdi was asked what she would tell a man who reads this headline and worries about his own hormone levels for which she advised the following.

Clinically low testosterone, known as hypogonadism, is not diagnosed from a population trend or a single blood test. It requires both symptoms, such as low sex drive, fatigue, or low mood, and confirmed low levels on repeat morning blood tests. For most men, the more useful response to this study is attention to basic metabolic health:

• Maintaining a healthy weight

• Staying physically active

• Sleeping 7 to 9 hours a night

• Limiting alcohol

• Managing stress

All of these support healthy testosterone production without any prescription.

Is This Testosterone Decline Something to Worry About?

The finding of a roughly 54% drop in average testosterone since 1972 is consistent across several studies examined, and worth taking seriously as a signal about men's metabolic and reproductive health, especially in a country like India where obesity and diabetes are both rising quickly.

At the same time, this is preliminary, not-yet-peer-reviewed data, and the exact causes are still being worked out.

For now, the most evidence-based response is not panic or unsupervised use of testosterone boosters, but maintaining a healthy weight, staying physically active, sleeping well, managing stress, and seeking medical evaluation if persistent low testosterone symptoms develop. These lifestyle measures support overall metabolic health and remain the first step before considering hormone therapy.

REFERENCES

1. Anjana, R., R. Unnikrishnan, M. Deepa, et al. "Metabolic Non-Communicable Disease Health Report of India: The ICMR-INDIAB National Cross-Sectional Study (ICMR-INDIAB-17)." The Lancet Diabetes & Endocrinology 11 (2023): 474–489. https://doi.org/10.1016/S2213-8587(23)00119-5.

2. Mohan, D., R. Pradeepa, U. Venkatesan, et al. "High Prevalence of Metabolic Obesity in India: The ICMR-INDIAB National Study (ICMR-INDIAB-23)." The Indian Journal of Medical Research 161, no. 5 (2025): 461–472. https://doi.org/10.25259/IJMR_328_2025.

3. Levine, H., et al. "Temporal Trends in Total and Free Testosterone (1972-2019): A Systematic Review and Meta-Trend Analysis." Human Reproduction, Supplement 1, Abstracts of the ESHRE 42nd Annual Meeting, 2026. (Conference abstract supporting the age-stratified comparison and temporal trend analysis.)

   https://academic.oup.com/humrep/article/41/Supplement_1/deag083.202/8727608

4. Bhasin, S., Brito, J. P., Cunningham, G. R., et al. "Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline." The Journal of Clinical Endocrinology & Metabolism 103, no. 5 (2018): 1715-1744.

   https://academic.oup.com/jcem/article/103/5/1715/4939465