‘Spermmaxing’ explained as biohacker boasts his sperm is different to 4 billion men on the planet

A billionaire and self-described ‘biohacker’ has opened up about why his sperm is different to everyone else’s

Bryan Johnson has spent years attempting to fine-tune nearly every part of his daily life — from an intense morning schedule to strict health protocols — and he has now turned his attention to what some online circles call ‘spermmaxxing’.

The “-maxxing” concept first gained traction in incel internet spaces, drawing inspiration from video game character-building screens.

In many games, players distribute a limited pool of points into categories such as strength or agility. “Maxxing” describes the approach of pouring as much as possible into a single attribute rather than aiming for an even spread.

Offline, people have adapted the idea into self-improvement (and sometimes extreme) niches: working out for “strengthmaxxing,” pursuing wealth through “moneymaxxing,” or even attempting “ballmaxxing” by injecting saline into the scrotum to temporarily enlarge the testes.

Within that framework, “spermmaxxing” is about trying to maintain high, healthy sperm counts. Johnson, 48, recently claimed there’s one major way his semen now differs from before.

In a post on X, he said: “I have no microplastics in my balls. This should not be possible.

“I had 165 microplastic particles in my semen just 18 months ago. Now, I have zero.”

Microplastics are tiny pieces of plastic that form as larger items break down over time into smaller and smaller fragments — sometimes down to particle size.

Because they’re so small, they can make their way into food and water, and researchers have detected them across the planet, from remote ocean depths to the inside of human bodies.

In 2024, one study reported finding microplastics in every human testicle sample it examined.

So what does Johnson think changed?

He said he made three changes, but implemented them together rather than one-by-one, explaining: “I did all three interventions at the same time. I cannot say which one did the most work. What I can say is this: Going from 165 to zero in 18 months is possible.”

One step involved doing dry sauna sessions regularly. Another focused on reducing exposure to plastic by swapping plastic items for alternatives — a goal that can be difficult given how common plastic is in everyday life.

The third was installing a reverse osmosis water filter at home for drinking water, a system designed to remove certain contaminants.

The broader “spermmaxxing” trend has also been discussed by medical advisor Dr Allison Rogers, who connects it to a wider cultural push toward constant self-tracking and improvement.

She told Vice: “I see spermmaxxing as a byproduct of the ‘optimization age’ we are in, when everything, from sleep to fitness to diet, is being monitored, improved, and shared online.”