News | Research Focuses on Long-Term Changes in Male Hormones: Average Testosterone Levels Have Declined Significantly Over the Past 50 Years
An analysis presented at the 2026 Annual Meeting of the European Society of Human Reproduction and Embryology (ESHRE) shows that between 1972 and 2019, the average total testosterone level in men showed a continuous downward trend, with an overall decline of 54%. The research team believes that this change warrants continued attention from the perspectives of male reproductive health and overall public health. However, the study also suggests that metabolic factors such as obesity and diabetes may explain a considerable portion of this change, and the specific role of environmental exposure still needs further clarification.
A Cross-National Integrated Data Analysis Draws Attention
According to a report by The Guardian on July 7, this study was led by a research team from the Hebrew University-Hadassah Braun School of Public Health and Community Medicine in Israel and was presented during the ESHRE 2026 Annual Meeting.
The study is not a single cohort observation but rather integrates data from 6 previous longitudinal studies. These studies all included testosterone tracking information from at least 3 time points, encompassing a total of 118,593 men, involving Israel, the United States, Brazil, Finland, and Denmark, with a time span extending from 1972 to 2019.
The researchers reported that total testosterone levels in men showed a downward trend in each of the studies; after combined analysis, the overall decline was estimated at 54%, and the downward trend appeared to accelerate after 2000.
Why Testosterone Deserves Attention
Testosterone is an important male sex hormone, closely related not only to sperm production but also involved in libido, muscle mass, bone density, mood, energy, and metabolic regulation. Therefore, long-term changes in testosterone levels are not just a matter for reproductive medicine but may also reflect broader changes in health status.
Professor Hagai Levine, one of the study's lead researchers, stated in an interview that male reproductive health should be regarded as an important signal of overall health. If relevant indicators continue to decline, it is necessary to seek causes from multiple levels, including lifestyle, chronic disease burden, and environmental exposure.
Study Subjects, Methods, and Main Findings
In terms of study design, this work is an integrated analysis of previous longitudinal studies, with the advantages of a large sample size, long observation period, and coverage of multiple countries. The researchers focused primarily on the trends in total testosterone levels among male cohorts from different eras, rather than comparing the effects of a specific treatment.
Main findings include:
Between 1972 and 2019, the average total testosterone level in men declined overall by approximately 54%.
The downward trend was observed across different studies, not only in a single country or a single population.
The research team estimated that this trend corresponds to a decline of more than 1% per year.
In terms of temporal distribution, the downward trend may have been more pronounced after 2000.
These results bring the question of "whether male reproductive health is continuously weakening" back into the public eye. However, the study itself cannot directly answer all mechanistic questions, nor can it be inferred from these results alone that all individual men will experience the same changes.
Possible Causes Still Under Discussion
The report noted that the rise in obesity and diabetes is considered an important factor. Clinically, the relationship between obesity and low testosterone is clear; excess adipose tissue increases the possibility of testosterone conversion to estrogen, thereby affecting hormone levels. The research team also mentioned that metabolic syndrome may explain part of this downward trend.
At the same time, environmental factors have also been proposed as possible clues, including exposure to endocrine disruptors and climate change-related impacts. However, it must be emphasized that the relationship between such factors and testosterone decline is still under ongoing research and debate. Current evidence is insufficient to make definitive causal judgments regarding specific environmental exposures.
Limitations Must Be Acknowledged
Although this study has a large sample size and a long time span, it still has several limitations.
First, the study controlled for age, but other cohort differences may still exist between samples from different eras, affecting the interpretation of results. Second, obesity was not fully controlled for in all analyses, and it is highly correlated with low testosterone. In other words, the study observed a "trend," but it cannot fully separate which changes are attributable to metabolic issues and which may be related to environmental exposure.
Additionally, these results were presented as a research analysis at an academic annual meeting, and the information is mainly derived from conference reports and interview content, which is not equivalent to clinical conclusions that have undergone complete peer review. When interpreting this, the public should regard it as a scientific signal worthy of attention, rather than a definitive causal conclusion.
What It Means for Clinicians and the Public
From a reproductive medicine perspective, the importance of this study lies in the fact that it once again reminds people to pay attention to the role of the male factor in fertility issues. For a long time, discussions on infertility have often focused more on women, but male hormone levels, sperm quality, metabolic health, and lifestyle are equally critical.
For the public, the study cannot currently support conclusions such as "a single environmental factor is directly causing a male fertility crisis," nor can it be used to extrapolate unproven treatment recommendations. It is particularly noteworthy that experts in the report cautioned that promotional claims about testosterone replacement therapy on social media should be treated with caution, because exogenous testosterone may, in some cases, actually suppress sperm production.
A more prudent understanding is: male reproductive health deserves earlier screening and earlier intervention. Weight management, control of metabolic diseases, seeking standard medical care, and avoiding unnecessary hormone use remain the more practically meaningful directions at present.
Background Information
In recent years, research on trends in male reproductive health has been increasing, especially the relationship between sperm count, hormone levels, and metabolic health, which has become an important topic at the intersection of reproductive medicine and public health. The results presented at this ESHRE Annual Meeting once again bring long-term changes in male hormones back to the center of academic and public discussion, and also suggest that more high-quality research is needed in the future to clarify the mechanisms and modifiable intervention points.
Impact and Significance
The significance of this analysis lies not in providing a simple conclusion, but in providing a long-term trend signal worthy of caution. For clinicians, it suggests that male evaluation should not be limited only to semen analysis but should also incorporate a comprehensive assessment of hormones and metabolic health; for researchers, it raises clearer questions about how to distinguish the relative contributions of lifestyle, chronic disease burden, and environmental exposure in long-term changes; for the public, it once again emphasizes that reproductive health and overall health are not two separate matters.
Story Source:
Collected from the internet
Author LinkedIVF TeamPublished 2026-07-10
This article used AI assistance; LinkedIVF has not recorded an editorial review for this item. It is not medical advice.
This content is for informational purposes only and does not constitute medical advice. Please consult a licensed physician. Content guidelines & editorial policy
News | Study Focuses on Long-Term Changes in Male Hormones: Average Testosterone Levels Have Significantly Declined Over the Past 50 Years
News | Research Focuses on Long-Term Changes in Male Hormones: Average Testosterone Levels Have Declined Significantly Over the Past 50 Years
An analysis presented at the 2026 Annual Meeting of the European Society of Human Reproduction and Embryology (ESHRE) shows that between 1972 and 2019, the average total testosterone level in men showed a continuous downward trend, with an overall decline of 54%. The research team believes that this change warrants continued attention from the perspectives of male reproductive health and overall public health. However, the study also suggests that metabolic factors such as obesity and diabetes may explain a considerable portion of this change, and the specific role of environmental exposure still needs further clarification.
A Cross-National Integrated Data Analysis Draws Attention
According to a report by The Guardian on July 7, this study was led by a research team from the Hebrew University-Hadassah Braun School of Public Health and Community Medicine in Israel and was presented during the ESHRE 2026 Annual Meeting.
The study is not a single cohort observation but rather integrates data from 6 previous longitudinal studies. These studies all included testosterone tracking information from at least 3 time points, encompassing a total of 118,593 men, involving Israel, the United States, Brazil, Finland, and Denmark, with a time span extending from 1972 to 2019.
The researchers reported that total testosterone levels in men showed a downward trend in each of the studies; after combined analysis, the overall decline was estimated at 54%, and the downward trend appeared to accelerate after 2000.
Why Testosterone Deserves Attention
Testosterone is an important male sex hormone, closely related not only to sperm production but also involved in libido, muscle mass, bone density, mood, energy, and metabolic regulation. Therefore, long-term changes in testosterone levels are not just a matter for reproductive medicine but may also reflect broader changes in health status.
Professor Hagai Levine, one of the study's lead researchers, stated in an interview that male reproductive health should be regarded as an important signal of overall health. If relevant indicators continue to decline, it is necessary to seek causes from multiple levels, including lifestyle, chronic disease burden, and environmental exposure.
Study Subjects, Methods, and Main Findings
In terms of study design, this work is an integrated analysis of previous longitudinal studies, with the advantages of a large sample size, long observation period, and coverage of multiple countries. The researchers focused primarily on the trends in total testosterone levels among male cohorts from different eras, rather than comparing the effects of a specific treatment.
Main findings include:
Between 1972 and 2019, the average total testosterone level in men declined overall by approximately 54%.
The downward trend was observed across different studies, not only in a single country or a single population.
The research team estimated that this trend corresponds to a decline of more than 1% per year.
In terms of temporal distribution, the downward trend may have been more pronounced after 2000.
These results bring the question of "whether male reproductive health is continuously weakening" back into the public eye. However, the study itself cannot directly answer all mechanistic questions, nor can it be inferred from these results alone that all individual men will experience the same changes.
Possible Causes Still Under Discussion
The report noted that the rise in obesity and diabetes is considered an important factor. Clinically, the relationship between obesity and low testosterone is clear; excess adipose tissue increases the possibility of testosterone conversion to estrogen, thereby affecting hormone levels. The research team also mentioned that metabolic syndrome may explain part of this downward trend.
At the same time, environmental factors have also been proposed as possible clues, including exposure to endocrine disruptors and climate change-related impacts. However, it must be emphasized that the relationship between such factors and testosterone decline is still under ongoing research and debate. Current evidence is insufficient to make definitive causal judgments regarding specific environmental exposures.
Limitations Must Be Acknowledged
Although this study has a large sample size and a long time span, it still has several limitations.
First, the study controlled for age, but other cohort differences may still exist between samples from different eras, affecting the interpretation of results. Second, obesity was not fully controlled for in all analyses, and it is highly correlated with low testosterone. In other words, the study observed a "trend," but it cannot fully separate which changes are attributable to metabolic issues and which may be related to environmental exposure.
Additionally, these results were presented as a research analysis at an academic annual meeting, and the information is mainly derived from conference reports and interview content, which is not equivalent to clinical conclusions that have undergone complete peer review. When interpreting this, the public should regard it as a scientific signal worthy of attention, rather than a definitive causal conclusion.
What It Means for Clinicians and the Public
From a reproductive medicine perspective, the importance of this study lies in the fact that it once again reminds people to pay attention to the role of the male factor in fertility issues. For a long time, discussions on infertility have often focused more on women, but male hormone levels, sperm quality, metabolic health, and lifestyle are equally critical.
For the public, the study cannot currently support conclusions such as "a single environmental factor is directly causing a male fertility crisis," nor can it be used to extrapolate unproven treatment recommendations. It is particularly noteworthy that experts in the report cautioned that promotional claims about testosterone replacement therapy on social media should be treated with caution, because exogenous testosterone may, in some cases, actually suppress sperm production.
A more prudent understanding is: male reproductive health deserves earlier screening and earlier intervention. Weight management, control of metabolic diseases, seeking standard medical care, and avoiding unnecessary hormone use remain the more practically meaningful directions at present.
Background Information
In recent years, research on trends in male reproductive health has been increasing, especially the relationship between sperm count, hormone levels, and metabolic health, which has become an important topic at the intersection of reproductive medicine and public health. The results presented at this ESHRE Annual Meeting once again bring long-term changes in male hormones back to the center of academic and public discussion, and also suggest that more high-quality research is needed in the future to clarify the mechanisms and modifiable intervention points.
Impact and Significance
The significance of this analysis lies not in providing a simple conclusion, but in providing a long-term trend signal worthy of caution. For clinicians, it suggests that male evaluation should not be limited only to semen analysis but should also incorporate a comprehensive assessment of hormones and metabolic health; for researchers, it raises clearer questions about how to distinguish the relative contributions of lifestyle, chronic disease burden, and environmental exposure in long-term changes; for the public, it once again emphasizes that reproductive health and overall health are not two separate matters.
Story Source:
Collected from the internet