Bryan Johnson Reports Reducing Microplastics in Semen to Zero

Bryan Johnson, 48, reported that the concentration of microplastics in his semen fell from 165 particles per milliliter in November 2024 to zero last month. " He stated he is "the first human ever to show a complete reduction to zero" and shared the protocol he followed.

Microplastics have been found in nearly all human organs and tissues, including testicles and sperm. Studies have linked them to lower sperm concentration, more abnormally shaped sperm and reduced fertility. Johnson said sperm count serves as one of the "cleanest biomarkers of overall health" even for men not seeking to have children.

Johnson said he applied three measures simultaneously and could not determine which contributed most. The first involved daily sessions in a dry sauna set to 200 degrees Fahrenheit for 20 minutes while applying an ice pack to the groin area. He reported that blood tests confirmed the sauna cleared plastic-related chemicals including BPA, phthalates, PFAS, flame retardants and pesticides.

Johnson noted that the plastic particles themselves are too large to exit through sweat but that heat may activate other clearance pathways such as bile flow, the gut barrier and cellular cleanup systems. The second intervention used a purification system with a semipermeable membrane to filter tap water.

Research cited in his post found an average of 325 plastic particles per liter in bottled water compared with 5.5 particles per liter in tap water. Johnson acknowledged that eliminating all plastic exposure remains difficult.

Johnson described microplastics inside the body as causing "a kind of cellular rust" that triggers inflammation in the testicles, kills sperm-producing cells and lowers testosterone. He has previously shared details of extreme anti-aging measures applied to various parts of his body.

Some studies suggest high heat exposure can negatively affect sperm quality, though it remains unclear whether combining sauna use with groin cooling changes that dynamic. Johnson said the overall results, while not definitively proven to stem from the interventions, showed a measurable change from 165 particles per milliliter to 20 by July 2025 and then to zero.

"I did all three interventions at the same time. I cannot say which one did the most work," he wrote.