Where Has All the Testosterone Gone?
Levels of the hormone have dropped in the past half century—but no one knows exactly why.
The Trump administration's interest in testosterone appears to be significant. Health Secretary Robert F. Kennedy Jr. once stated that the president's testosterone levels were notably high for a man of his age, a claim for which he is known to supplement with himself. In April, the FDA aimed to increase accessibility to testosterone-replacement therapy for a larger number of men.
Moreover, Defense Secretary Pete Hegseth recently announced that older "warfighters" above the age of 30 would undergo annual testosterone assessments to maintain their "leading edge of lethality." However, experts seem skeptical about the necessity of extensive testing or testosterone replacement. Despite most men's testosterone levels remaining within the normal range, average testosterone has been declining among men for several decades.
According to a review of studies involving over a million men globally, blood testosterone levels had dropped by approximately 20 percent in the last half-century. A recent unpublished study suggests the decrease could be as much as 50 percent. Scientists remain uncertain about the cause of this decline, but some suspect environmental factors, such as endocrine-disrupting chemicals like phthalates and PFAS found in plastics and non-stick cookware.
Lifestyle changes, such as decreased physical labor, obesity, and aging, are also considered contributing factors. Obesity, which affects around 14 percent of the global male population, can suppress testosterone levels as fat tissue contains enzymes that convert testosterone into estrogen. Regardless of the cause, the decline is concerning because testosterone is essential for mood, sexual function, energy levels, muscle, heart, and bone health.
Low testosterone may lead to decreased libido, fatigue, depression, muscle loss, and fertility issues. While there is no straightforward solution, medical experts recommend individual assessments for those suspecting low testosterone, as widespread monitoring, as proposed by Hegseth, would not be beneficial for the majority.
Written by urgent.news from The Atlantic's reporting — not their text. Machine-written — it may contain errors, so check the original before relying on it.
