What the gut microbiome actually does
Half Human
And what the evidence says about everything you’ve been sold.
The microbiome is one of the most genuinely exciting frontiers in medicine. It is also one of the most oversold. This book separates the two, claim by claim, and tells you which is which.
Kindle and paperback · 361 pages · Published 24 July 2026
The premise
You are outnumbered. The cells carrying your DNA share the body with trillions of microorganisms carrying their own. That much is settled, and it is genuinely strange.
What follows from it is where the trouble starts. A finding in mice becomes a headline about humans. An association becomes a cause. A supplement gets sold on the strength of a study that never tested it.
This book walks through what the research supports, what it merely suggests, and what has been attached to it by people with something to sell. When the evidence is strong, it says so. When a result comes from mice, it says in mice, every time.
Who wrote it
Rafik Fellague-Chebra, MD, is a physician who has spent twenty-five years in global oncology drug development and medical affairs, across academia and large pharmaceutical companies.
Twenty-five years of watching most compounds fail produced the discipline behind the writing: a refusal to let a result mean more than it has earned.