Men’s testosterone has been in decline for decades, as we supposedly slide toward becoming “girly-men”, to borrow from Arnie. But now, apparently, the great testosterone slide is over. Woo-hoo!
Renaissance Periodization has picked up on new US research suggesting low testosterone is becoming less common. It makes for a cracking headline and societal collapse less likely. Or does it?
The problem is that a recent drop in the number of men below a clinical cut-off is not the same as reversing a decades-long decline in average testosterone. So, has testosterone really bounced back, or has the good Doctor’s headline outrun the evidence?
What the new study found
The study, published in the American Journal of Men’s Health, analysed 10,357 American men surveyed between 2011 and 2023.
Low testosterone was defined as a total testosterone reading below 300 ng/dL, equivalent to about 10.4 nmol/L. Men reporting testosterone use were excluded, and the researchers used standardised laboratory methods.
The age-standardised proportion of men below the cut-off fell from 29.3 per cent in 2011–2012 to 22.4 per cent in 2021–2023. That is a substantial change, and it was not simply caused by differences in the ages of the men sampled.
It is the finding behind the Renaissance Periodization video, The Testosterone Decline Story Is Dead. We have previously checked Dr Mike Israetel’s claims about the only five supplements worth taking. This time, his argument is that the familiar story of an uninterrupted testosterone collapse no longer fits all the available evidence. He is right about that. The new data complicates the story. It does not kill it.
What the new study actually found
Higher odds of low testosterone: obesity, high blood glucose and prolonged sitting were all associated with deficiency.
The study found a decline, but did not establish what caused it.
The testosterone decline was real
The original decline story did not emerge from an angry bloke with a podcast microphone. The landmark Massachusetts Male Aging Study analysed 1,532 men across three collection periods between 1987 and 2004. It found an age-independent decline in testosterone that could not be fully explained by changes in obesity, smoking, medication use or general health.
An Israeli study of 102,334 men found a similar age-independent decline in testosterone tests conducted between 2006 and 2019. Rising obesity did not appear to explain it, although these were men whose doctors had ordered tests rather than a randomly selected national sample.
More recently, a 2025 systematic review covering more than one million healthy men found a downward trend in testosterone and luteinising hormone across studies published from 1971 to 2024. The result remained after accounting for age, body mass index and testing method, although combining many different studies creates limitations of its own.
So yes, testosterone appears to have declined across several populations. The new study does not prove those earlier findings were wrong.
Fewer deficient men is not a complete recovery
The distinction is simple. The new study counted the percentage of men below one threshold. It did not show that average testosterone had returned to the levels recorded in the 1980s or 1990s.
Think of it like an exam. If fewer students fail this year, that is encouraging. It does not necessarily mean the class average has returned to where it was 30 years ago.
Dr Mike makes the same point in the video: the bottom of the testosterone distribution could improve without every part of it rising equally. Testosterone may have fallen for decades and then partially recovered. Both findings can be true.
The 300 ng/dL line is also not a biological cliff. A man testing at 299 is not fundamentally different from one testing at 301, and neither reading diagnoses clinical testosterone deficiency on its own.
Why might testosterone be recovering?
This is where the result gets interesting. Obesity is one of the strongest known predictors of low testosterone. In the new study, men with obesity had 2.69 times the odds of falling below the cut-off, while diabetes-range fasting glucose almost tripled the odds.
Yet obesity among the sampled men increased from 35.1 to 38.9 per cent while low testosterone became less common. If obesity were the only force driving the trend, the numbers should have moved in the opposite direction.
Extreme sedentary time declined from roughly 40 to 36 per cent, and access to regular healthcare improved slightly. Those changes may have helped, but the study cannot prove they caused the rebound.
There were also differences in testing conditions, a large COVID-era gap in the data and potentially unreported use of testosterone or other hormone-altering drugs. The researchers sampled different men during each survey rather than following the same group for 12 years.
The honest answer, also given by Dr Mike, is that nobody yet knows why the prevalence fell.
What can you do about your own testosterone?
Population averages cannot tell you what is happening inside your body. Your sleep, weight, health, medication, diet, training and fertility goals matter far more than whether the American average moved up or down.
Aim for seven to nine hours of sleep and take sleep apnoea seriously. If obesity is present, losing excess body fat is probably the most reliable broadly applicable way to improve natural testosterone.
The reverse matters too. Prolonged crash dieting, inadequate energy intake and trying to maintain extremely low body fat can suppress testosterone. Eat enough total energy, protein and essential fats, with a reasonable spread of fruit, vegetables and other nutrient-rich foods.
Lifting is useful for strength, muscle and body composition, but the temporary testosterone rise after a workout does not permanently reset your baseline. Too much hard training without adequate recovery can push it down instead.
Porn, masturbation, soy, hot showers and tight underwear have all been blamed for declining male hormones. None provides a convincing explanation for a decades-long population trend. Abstinence rituals and most commercial testosterone boosters are not the answer either.
If your concerns are primarily about libido or erections, testosterone is only one of the factors that can limit sexual performance. Fatigue, poor sleep, depression, diabetes, medication and cardiovascular health can produce similar problems.
Sources
- New study Goulian et al: Testosterone deficiency in US men, 2011–2023
- Video analysis Renaissance Periodization: The Testosterone Collapse Is a Lie!?
- Earlier research Population-level decline in serum testosterone levels in American men
- Earlier research Decline in testosterone among adolescent and young adult men
- Systematic review Temporal trends in testosterone and luteinising hormone
- Clinical guidance Healthy Male: Diagnosing and treating androgen deficiency
