No, testosterone levels in men haven’t decreased by 50 percent in recent years

What is the claim?

Posts on social media claim that the average testosterone level of males has declined by 50 percent over the last two decades. In one such post on TikTok (archived here) a user claims, “Did you know that 20-year-old men on average today have testosterone levels that 70-year-old men had in 2000?”

Similar claims have been circulating at least since 2021. Archived versions of such posts can be viewed here, here, here, and here. 

Screenshot of posts making the claim. (Source: X/TikTok/Screenshot/Modified by Logically Facts)

However, according to medical experts and available studies, data does not suggest there has been a 50 percent decrease in testosterone levels over the past 20 years.

What are the facts? 

We traced the claim to an article published by the website “American Greatness,” an editorial outlet that focuses on content related to "next generation conservatism," on January 4, 2021. The phrases in the viral claim have been picked from the article, which states, “The average 22-year-old man today has an average testosterone level roughly equal to that of a 67-year-old man in 2000.” 

The article includes data from two studies, one conducted in 2007 and another from 2021, that researched testosterone levels in males in the U.S. The 2007 study, titled “A Population-Level Decline in Serum Testosterone Levels in American Men,” conducted by the New England Research Institutes in Watertown, Massachusetts, collected 2,769 observations from 1,532 men and observed a "substantial" drop in U.S. men's testosterone levels since the 1980s. However, the reasons for this decline remain unclear. Reuters reported the study's details, which noted an average one percent decline in male hormones yearly. 

From this, we could infer that a 70-year-old man in 2024 would have testosterone levels 20 percent lower than those of 70-year-old in 2004 (two decades before 2024), not a 50 percent reduction, as claimed in the post. 

Another study in 2021, published in the European Urology Focus journal, also said that testosterone levels for 4,045 men in the U.S. declined from 1999 to 2016. However, it added that more studies are required to understand the cause of low testosterone.

Logically Facts spoke to Stefan Arver, a professor at Karolinska Institutet in Sweden, who told us that the claim is untrue. “There is no data to support such a statement.”

He added, “Observational studies from Denmark (CPH region) and the U.S. East Coast have reported on a secular trend, but there are no mechanisms that have been demonstrated that could support the trend. One issue is confounders like an increased prevalence of obesity. Obesity suppresses testosterone total levels to some extent, but the free fraction of testosterone may be persistent due to lower levels of a binding protein (SHBG)."

Prof. Arver said that the normal range for testosterone levels can vary, and such overall average changes “may still be ok if the proportion of men who fall below a symptom threshold is unchanged.”

“However, bias in selecting participants can be misleading. Therefore, any conclusions should be supported by evidence, and the data should be free from common confounders,” he told us.

He also added that the decrease in levels raises concerns about male testicular health, including lower sperm production and quality and a higher rate of genital malformations and testicular cancer in some regions. These issues could be linked to environmental factors such as pollution and pesticides.

Endocrinologist Dr. Vinayak Harale, based in India, told Logically Facts, “As men get older, their testosterone levels may decline about one percent per year after the age of 30.” He added that no data supports the claim that the levels have decreased to 50 percent in the last two decades. The expert also highlighted that possible reasons for lower testosterone could be lifestyle changes, high cholesterol, obesity, and diabetes.

The verdict

While there has been a general decline in average testosterone levels in men, it has not been by 50 percent, as claimed in viral posts. Therefore, we have marked the claim as misleading.