Alarming drop in testosterone levels in young men
In rich countries, the endocrinology of average men is changing in an alarming way. According to American scientists, young men today have as much as a third less testosterone than the young men of 15 years ago.
Study
Soum Lokeshwar, an American physician and researcher, analyzed data from 4,045 men aged 15-39 collected in the National Health and Nutrition Examination Surveys in 1999-2016. He looked in particular at the total testosterone level.
Results
In the period studied, men became fatter. Their average BMI increased by just over 2 points. That increase was statistically significant.
During the same period, the men's total testosterone levels plummeted. In 1999-2000, the average was still close to 600 nanograms per deciliter. In 2015-2016 this was only 400 nanograms per deciliter. This equates to a decrease of about thirty percent.


Lokeshwar again measured the change in testosterone levels over time, but then only looked at the men with a 'healthy' BMI. When he brushed off this effect, and immediately did the same for other confounders such as chronic conditions and diseases, age, smoking, alcohol and exercise, testosterone levels still dropped significantly.
Causes?
Lokeshwar does not know what could explain the decrease in testosterone level he described. Perhaps men are getting more phytoestrogens through their diets, he suggests. Or maybe it's because of the growing popularity of marijuana. But whatever it is, it's an environmental factor.
Mechanism
We, the unwitting compilers of this website, suspect that deteriorated sleep habits are the main cause of declining testosterone levels. According to surveys, not only are we sleeping less and less, but the quality of our sleep has also deteriorated.
Source:
Eur Urol Focus. 2021 Jul;7(4):886-9.
In rich countries, the endocrinology of average men is changing in an alarming way. According to American scientists, young men today have as much as a third less testosterone than the young men of 15 years ago.

Study
Soum Lokeshwar, an American physician and researcher, analyzed data from 4,045 men aged 15-39 collected in the National Health and Nutrition Examination Surveys in 1999-2016. He looked in particular at the total testosterone level.
Results
In the period studied, men became fatter. Their average BMI increased by just over 2 points. That increase was statistically significant.
During the same period, the men's total testosterone levels plummeted. In 1999-2000, the average was still close to 600 nanograms per deciliter. In 2015-2016 this was only 400 nanograms per deciliter. This equates to a decrease of about thirty percent.


Lokeshwar again measured the change in testosterone levels over time, but then only looked at the men with a 'healthy' BMI. When he brushed off this effect, and immediately did the same for other confounders such as chronic conditions and diseases, age, smoking, alcohol and exercise, testosterone levels still dropped significantly.
Causes?
Lokeshwar does not know what could explain the decrease in testosterone level he described. Perhaps men are getting more phytoestrogens through their diets, he suggests. Or maybe it's because of the growing popularity of marijuana. But whatever it is, it's an environmental factor.
Mechanism
We, the unwitting compilers of this website, suspect that deteriorated sleep habits are the main cause of declining testosterone levels. According to surveys, not only are we sleeping less and less, but the quality of our sleep has also deteriorated.
Source:
Eur Urol Focus. 2021 Jul;7(4):886-9.