Microplastics not only exist in the environment, the tiny particles also accumulate in the body. And that everywhere. In 2024, studies examined the proportions of microplastics in the testicles and sperm of men. Not a single sample taken was free of microplastics. Tech entrepreneur and longevity fanatic Bryan Johnson says in a TikTok that he has the solution to the problem: daily, 20-minute visits to the 90-degree sauna.
Stress factor instead of detox
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He was able to reduce the amount of microplastics contained in his sperm by 85 percent. Sounds great, but does it really work and is it a good idea? Urologist Dr. med. Uwe Bieri doesn’t think so. He advises against the practice if you want to have children: “For the testicles, the heat in the sauna is more of a stressor than a detox.”
What are you personally doing to reduce your intake of microplastics?
Sweat out plastic
“There are currently no reliable studies that show that sauna sessions sweat out microplastics from the sperm,” says the doctor. Therefore, it is not certain whether Johnson’s results – if they are real – can really only be attributed to his sauna visits. “It’s not very biologically plausible. “Sweat glands are not particle filters, but primarily release water and small molecules.” Things look a little different with certain chemicals associated with plastic: “Bisphenol A, i.e. BPA, was detected in sweat in a study following indicated sweating.” However, Bieri points out that a single study with a few participants is not very meaningful.
Heat damages the testicles
“What is clear, however, is that regular exposure to heat on the testicles measurably worsens sperm count and motility.” This is reversible if you stop using the sauna again. “If you currently want to have children, this is a relevant topic.”
It’s no wonder that heat affects sperm so much: “The testicles are located slightly outside the body, under the abdominal area. This is because spermatogenesis, i.e. the formation of sperm, has to run cool, around 32 to 35 degrees.” According to the doctor, even small, repeated increases in temperature can disrupt the process. “In a study in which the participants only went to the sauna twice a week, significant deteriorations in sperm quality were found.” For the same reason, men who want to have children are advised against regular visits to whirlpools, using heated seats or placing their laptop on their lap, in addition to sauna sessions.
What really helps against microplastics in sperm?
If you want to reduce the microplastics in your testicles or sperm (and elsewhere in your body), advises Dr. Minimize exposure to plastic as much as possible. For example, you could avoid drinking from plastic bottles or not use plastic cutlery. The doctor also advises against heating food and drinks in plastic packaging in the microwave. “Reducing dust indoors can also help,” says the expert – because microplastics also enter the body through the air we breathe.
Ice doesn’t help in the heat
Johnson protects his testicles with ice during his sauna sessions – the solution to the heat problem? Dr. Bieri says no: “It is questionable whether a little ice can really reduce the temperature in a 90-degree sauna. This only cools the surface, not the core of the testicles.” In addition, according to Dr. Bieri increases the risk of cold injuries, such as local frostbite or skin damage.
How harmful are microplastics in sperm?
The effects of microplastics on your health have not been fully clarified either. Dr. Bieri makes it clear: “Detection of microplastics in sperm does not equate to the damage caused by it.” While the presence of microplastics in the testicles, semen and urine has been proven in several studies, it is not scientifically clear how this affects your fertility or health in the long term.
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Malin Mueller (mmu) has been working for 20 minutes since 2021. She is deputy director of lifestyle and beauty editor. Her focus: skin care, hairstyles and trend checks.