The pursuit of longevity has become a global obsession. From intermittent fasting to rapamycin experiments, self-styled “biohackers” pride themselves on testing the limits of human biology. They count calories, microdose things, and measure their telomeres. Yet there is one scientifically documented intervention that has extended lifespan for centuries—though you won’t see it trending on TikTok or appearing in a Silicon Valley lab. That intervention? Castration.
The clearest evidence comes from an unusual natural experiment in Korea. A study of 81 eunuchs, men castrated before puberty while serving in the royal courts, revealed that they lived on average 14 to 19 years longer than non-castrated males of the same era. That is a striking gap—comparable to eliminating nearly all the risks of smoking and obesity combined.
Other historical records back the trend. Castrated singers in Renaissance Europe often outlived their intact peers. Similar patterns have been spotted in livestock, where castrated animals consistently survive longer.
Rodent studies take this to an extreme. Remove the testes of a male mouse and its lifespan can increase by more than 50%. This isn’t marginal longevity—it’s transformative. Scientists attribute the effect to reduced testosterone-driven metabolic strain, lower cancer risk and shifts in immune function.
Of course, the trade-offs are obvious. The hormonal consequences are severe: altered muscle mass, body composition, fertility and sexuality. This is why castration remains a theoretical curiosity in human longevity research rather than a practical “biohack.”
The modern longevity movement thrives on pushing limits: megadoses of supplements, extreme caloric restriction, self-experimentation with pharmaceuticals. But where is the line? Few—if any—biohackers have dared to test what may be one of the most reliable lifespan-extending interventions known to biology.
Perhaps that silence says everything. Science may prove the method, but culture and psychology keep it firmly off the table. So while investors pour billions into gene editing, senolytics and cryonics, the oldest and cheapest intervention sits ignored. Waiting, perhaps, for the first brave—or reckless—biohacker to pilot the unthinkable.
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Min, K. J., Lee, C. K., & Park, H. N. (2012). The lifespan of Korean eunuchs. Current Biology, 22(18), R792–R793.
Snyder, D. L., & Fitch, W. L. (1989). Effects of castration and anabolic steroid treatment on body weight and lifespan of male rats. Mechanisms of Ageing and Development, 48(3), 267–272.
Yanai, S., & Endo, S. (2021). Sex differences in longevity and the role of gonadal hormones: Insights from animal studies. Experimental Gerontology, 147, 111257.