How this site works

We read the primary literature so you do not have to. Every guide here is assembled from peer-reviewed research, with each number linked to the study it came from. We are researchers and writers, not clinicians, and nothing here replaces a consultation.

Where the numbers come from

Every guide here is built from peer-reviewed research indexed in PubMed, the US National Library of Medicine's database. Each number in an article — a threshold, a dose used in a trial, a percentage — carries a superscript that links to the exact paper it came from, and the sources are listed in full at the bottom of every page.

Where the evidence is thin, contested or comes from a small study, the article says so in the sentence that uses it. Where a question has not been studied properly, we say that too.

Who writes the column

Max Zimin — Founder, Max Hormone Labs. I am not a clinician, and that is the point: I had no stake in defending the ranges. I read the primary literature and the laboratory guidance, I find out who chose a number and in what year, and I write it down with the document attached. I also write the books sold on this site. Everything in a column can be checked against its source, because that is the only kind of argument worth making here.

The Receipts is written in the first person because it makes an argument, and an argument should have somebody's name on it. Every claim in it about who set a threshold, when, and from which population carries the document it came from. Where a claim cannot be documented, it does not get published — that rule is enforced automatically, not by good intentions.

The column criticises mechanisms: reference intervals derived from the wrong population, thresholds that have not moved while the evidence did, ten-minute appointments that leave no room to ask where a number came from. It does not criticise the people working inside those constraints, and it will never suggest that you avoid care. The opposite: the point of every column is to send you back into the room with a better question.

What we are not

We are researchers and writers, not clinicians. Nothing on this site is a diagnosis, a prescription or a treatment plan. We do not tell anyone to start, stop or change a medication, and we do not sell supplements or take affiliate commission on them.

What we do sell is two books, listed openly in the menu. The guides are complete on their own; a reader who buys nothing should still leave with the answer she came for.

Reviews and corrections

Each page shows the date it was last reviewed. If you find a number that does not match its source, write to us and we will correct it and say so on the page.