Social media’s spheres have been abuzz with new research that reveals a decline in testosterone in men. The worry of men becoming more effeminate has been around in written media for decades. Some people target face creams, juice boxes or electronics as culprits of “feminizing” men. Even prominent figures like Health and Human Services Secretary Robert F. Kennedy Jr. is declaring a drop in testosterone levels an “existential problem”.
Whatever reasoning is made as to the decline, the research around the world is clear. Research indicates that there is a generation-on-generation slide in testosterone. Studies show that American men born in 1970 averaged higher hormone values than equally aged persons born 3 decades later.
Scientists call this secular decline “age-independent” because the drop remains after adjusting for birthdays. Decreasing testosterone levels are now being recorded in teenagers, young adults, and seniors alike. However, it is important to separate scientific evidence from sensationalism to understand why testosterone levels are dropping in modern men.
A Generational Downshift in Hormone Levels
U.S. health guidelines define normal testosterone levels as any value above 11.1 nmol/L, with 6.9 nmol/L as the lowest acceptable limit. European Union guidelines set the normal range slightly higher, accepting levels above 12 nmol/L and no lower than 8 nmol/L. Human sperm counts have dropped more than 50% globally, according to a 2022 review from the Human Reproduction Update journal.
This staggering decline appeared over 5 decades. Data from between 1973 and 2018 was used in the review and sparked debate. Some fertility experts caution the methodology for recording sperm count has changed over time, affecting the outcomes. Other medical professionals support the findings.
Population scientists worry about this decline because lower testosterone increases risks for diabetes, osteoporosis, and cardiovascular disease later in life. A 2020 U.S. analysis in young men found levels slipping fastest in those under 40, raising concern for future fertility. Together, these large datasets confirm that decreasing testosterone levels are no longer confined to aging men; they mark a public-health warning.
Body Weight
Overweight or obese individuals record lower testosterone levels. This is due to excess body fat that converts testosterone into estrogen. The Massachusetts Male Aging Study showed that going from a normal weight (BMI 25) to obese (BMI 29) drops testosterone levels significantly. This weight gain has the same hormonal impact as aging 10 years. Obesity also drives insulin resistance and inflammation, both of which suppress testicular output. With global obesity tripling since 1975, weight gain likely pushes the single largest modifiable pressure on male testosterone levels.
Dietary Patterns
This decline in testosterone has happened too rapidly, ruling out genetic adaptation. However, a modifiable culprit is diet. A recent meta-analysis published in Nutrition and Health by UK researchers revealed consuming too much protein can significantly reduce testosterone levels. The meta-analysis of intervention trials found low-carbohydrate diets reduced total testosterone in men even after weight and activity were controlled.
The study revealed that diets composed of more than 35% protein decreased testosterone levels by 37%. Ultra-processed foods add another layer of trouble by promoting obesity. These foods also expose diners to endocrine-disrupting additives, which are toxins believed to lower testosterone levels. However, research on these environmental toxins on hormones are still ongoing and remains inconclusive.
Sleep Disruption and Apnea
Testosterone levels typically peak during the morning after sleeping. Conditions such as sleep apnea break up those cycles leading to disrupted normal sleep. Disrupting the sleep cycle, in turn, disrupts the natural production of testosterone. Excessive screen time disrupts normal sleep and may lead to a disruption of testosterone.
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Alcohol
Chronic drinking damages Leydig cells and diverts key enzymes toward ethanol metabolism. Controlled trials showed significant testosterone drops within 5 days of heavy drinking. Heavy alcohol also raises cortisol, a stress hormone that antagonizes testosterone production.
Environmental Chemicals Under Suspicion
More than 800 industrial compounds act as endocrine disruptors. Phthalates, common in plastics and personal-care products, are associated with lower testosterone in both adult and adolescent males. Although research on its impact on hormones is still ongoing, several precautions can help reduce exposure. Minimizing microwaving in plastic, choosing phthalate-free toiletries, and improving ventilation when handling solvents represent prudent, low-cost safeguards.
Age Still Matters
Natural aging lowers testosterone production about 1% yearly after the age of 30. However, the current generational fall is steeper than that biological glide path. Researchers estimate that lifestyle and environmental pressures can double the annual decline. Age remains an immutable factor, yet its impact now compounds with weight gain, poor sleep, dietary shifts, toxins, and inactivity, accelerating the march toward clinically low hormone levels.
Can the Downward Drift Be Reversed?
Longitudinal evidence suggests comprehensive lifestyle change can slow or partly reverse decreasing testosterone levels. Men who lost 10% of body weight through combined diet and high-intensity resistance sessions raised baseline testosterone by up to 15% within 12 months.
Prioritizing 7 to 8 hours of proper sleep, trimming heavy drinking, and selecting unprocessed foods amplified gains. Sustaining healthy testosterone ultimately mirrors sustaining health in general: stay lean, move explosively, eat whole foods, sleep deeply, moderate toxins, and monitor regularly.
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