Microbes outnumber human cells in the human body by a factor of ten.

the verdict

REFUTED

the evidence says no

Recorded sources

0 sources for · 2 against

Counts group repeated records of the same source within each side. They do not measure evidence strength or source independence.

Recent scientific re-evaluations have refuted the long-standing belief that microbes outnumber human cells by a factor of ten, demonstrating that the actual ratio is approximately one-to-one.

The analysis

Papers [0] and [3] explicitly examine the historical 10:1 ratio and refute it with updated calculations, showing the true ratio is roughly 1:1. Papers [1], [2], [4], [5], [6], [7], and [8] are tangential and discuss various other aspects of microbiomes.

Evidence against · 2

Revised Estimates for the Number of Human and Bacteria Cells in the Body.

Recorded source metadata

Ron Sender, Shai Fuchs, Ron Milo. Revised Estimates for the Number of Human and Bacteria Cells in the Body.. 2016. https://doi.org/10.1371/journal.pbio.1002533

This study revises estimates of human and bacterial cells in the body, showing that the ratio is actually close to 1:1 rather than 10:1.

Source citation format

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More against · 1

Are We Really Vastly Outnumbered? Revisiting the Ratio of Bacterial to Host Cells in Humans.

Recorded source metadata

Ron Sender, Shai Fuchs, Ron Milo. Are We Really Vastly Outnumbered? Revisiting the Ratio of Bacterial to Host Cells in Humans.. 2016. https://doi.org/10.1016/j.cell.2016.01.013

This paper revisits the widely cited 10:1 bacterial-to-human cell ratio and finds that the true ratio is much closer to 1:1.

Source citation format

The paper trail · every fact has a biography

first checked31 Jul 2026

judged → REFUTED · 1031 Jul 2026

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