Does an Infrared Sauna Actually Detox Your Body?

This deserves a direct answer, because it’s the single most-cited piece of “evidence” behind the current wave of infrared sauna detox content, and ignoring it would look like BWC either hasn’t seen it or is avoiding it.

What was reported. Tech entrepreneur Bryan Johnson publicly shared lab results showing an 85% reduction in microplastic particle counts in his blood and ejaculate over roughly a year of daily sauna use, alongside reported reductions in several other environmental toxin markers. In a later update, he reported a further reduction — down to a single particle per millilitre in one blood sample. These are striking numbers, and it’s worth understanding precisely what they do and do not show.

Here are three things worth knowing before treating this as evidence of anything about sauna specifically.

First, sauna was not the only variable. In Johnson’s own account of the later reduction, he listed three new interventions introduced in the same window: daily sauna, Total Plasma Exchange (TPE), and an effort to remove as much plastic from his life as possible — including installing a reverse osmosis water filtration system and eliminating plastic cutting boards and plastic-safe microwaving. TPE is a medical procedure that directly filters and replaces blood plasma. It would reduce circulating microplastic particle counts on its own, with zero involvement from a sauna. Reverse osmosis filtration is independently well-documented as highly effective at removing microplastics from drinking water — meaning his intake may have dropped sharply at the same time his exposure was being measured. When three variables change at once and only one gets the headline, that’s a marketing story, not a scientific finding.

Second, the protocol described isn’t infrared. Johnson has specifically stated the effect requires a high-heat, low-humidity traditional dry sauna in the 176–212°F (80–100°C) range, and has said infrared saunas and lower-temperature units don’t replicate the skin-to-core temperature gradient he believes is responsible. Whatever is or isn’t happening in his self-experiment, by his own description it isn’t a claim about infrared sauna use in the first place — the exact product category most of the current “sauna detox” content, and this post, is about.

Third, this is a self-experiment, not a controlled study. One person, no blinding, no control group, multiple simultaneous interventions, and lab methodology that has not been independently published or peer-reviewed. A single individual’s before-and-after numbers cannot establish that any one intervention caused the result — let alone establish a mechanism that applies to anyone else.

What is genuinely well-established is that microplastics have been detected in human blood and other tissue, and this is a legitimate area of ongoing scientific concern.² What is not established is that sweating — through any type of sauna, infrared or traditional — is the mechanism by which the body clears them. Johnson’s numbers are a compelling personal data point that has been widely shared without the confounders attached. They are not evidence that sauna use detoxifies the body of microplastics.