Bryan Johnson's Testicle Icing Experiment: Biohacker Claims Fertility Boost, Redditors Follow Suit

Bryan Johnson is a longevity influencer who claims to have spent millions of dollars tracking and streamlining nearly every aspect of his biology in order to slow down or reverse ageing. At 48, he is undeniably fit, sleeps more than 8 hours and has a fertile age, or so he claims. Over the years, he has tracked his erections, injected his son's plasma into himself and monitored his girlfriend Kate Tolo's vaginal microbiome, all to prove a point. Now, his latest experiment involved ice packs and male testicles, inspiring half a million Redditors to follow suit, as per a report by VICE. Johnson, the billionaire biohacker behind Project Blueprint claims that 27 daily sauna sessions with an ice pack strapped to his groin produced a 57% increase in total motile sperm count, a 26% jump in concentration and improvement across morphology and motility. He posted the numbers to X himself, describing the ice protocol as the single most important variable in his sauna routine. He also says he has four times the average sperm count. These are his own figures, from his own experiments, on himself. Redditors are believed to be some of the most unique individuals on the planet who are suspicious of everything and yet willing to believe most. The Reddit biohacking community, which has over 555,000 weekly visitors, has now been running its own informal trials. “My protocol is super simple: ice pack over my boxers, 15 minutes per session, three to four times a day,” one user wrote, per Metro. After a year, he reported his highest-ever testosterone levels on a blood test, more powerful ejaculations, and a sex drive that was, in his words, “through the roof. ”

Can icing truly boost male fertility?

A 2005 nocturnal scrotal cooling over 8 to 12 weeks produced significant increases in sperm concentration and total count.

The experiment does have a base. Testicles hang outside the body since sperm production requires a temperature a couple of degrees below core body temperature, around 95 degrees Fahrenheit. A 2005 study on men with fertility issues, published in the International Journal of Andrology, found that nocturnal scrotal cooling over 8 to 12 weeks produced significant increases in sperm concentration and total count. A 2013 systematic review published in the Journal of Obstetrics and Gynaecology also found scrotal cooling beneficial for male fertility, with an important caveat. Those studies used mild, wearable cooling devices worn overnight, not ice packs applied multiple times a day. The science behind this is more complicated than Johnson's claims. Urologist Lye Diwa told VICE that "although there are small studies that would attest to cold temperature and improvement in sperm quality, there are no large clinical trials that would advise icing as a means to improve sperm count." Another expert, Martin Gross, an associate professor of surgery at Dartmouth, told Verywell Health there's no evidence that icing improves testosterone or sperm production. He advised that sleep, exercise, weight management and cutting back on alcohol are considerably more effective.

Bryan Johnson and biohacking

Despite the care and tests, Johnson still developed an autoimmune disease

Biohacking is the practice of using science, data and self-experimentation to optimise physical and mental performance, longevity and overall well-being. Over the years, interest in this field has grown enough for tech giants to release products like rings and watches that track human health and for food companies to launch diet-specific condiments. With the human ecosystem being symbiotic with the internet, influencers who ace at biohacking such as Johnson have also leveraged a large following and trust. However, health still remains individual to all and cannot be the same or similar to one another. For instance, despite being fit and spending whopping amounts on tracking his health, Johnson recently announced that he had developed a chronic autoimmune condition, called autoimmune gastritis. The disease causes “irreversible damage” to the lining of the stomach, he said, and often develops silently and asymptomatically over the course of years. He was diagnosed in May, he wrote, after years of persistently low ferritin, a protein that stores iron inside cells, that his team struggled to explain. According to Dr Gian Corrado, autoimmune disorders are quite common, even in apparently healthy and fit individuals. Thus, despite the care and tests, Johnson still developed one. When it comes to male fertility, the testosterone levels have dropped 54% between 1972 and 2019, driven by environmental factors such as heat exposure and microplastics. Men have often expressed anxiety over the same on online forums. But no matter what, the effectiveness of putting ice packs on testicles is still debatable and not completely practical.