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Corrections

If You Can't Check It, It Isn't Evidence

I repeated claims I could not verify, to people who paid me, on the authority of someone I trusted. Then I went back to audit them and found the material was no longer available to me.

STEPHEN DUNCAN FDN-P BSC HONS MSC · DETECTIVE HEALTH · AUGUST 2026

Every practitioner in my field says their approach is evidence-based. I say it. It appears on my website.

The phrase has become close to meaningless, and I want to explain what I think it should mean, using an example where I was on the wrong side of it.

The problem with the phrase

"Evidence-based" is usually deployed as a claim about the quality of someone’s thinking. It should be a claim about inspectability.

The question is not "does this practitioner believe there is evidence?" Almost everyone does. The question is: can I go and look at it?

If a claim comes with a citation you can find, read, and assess — that is evidence-based. If it comes with an assurance that the evidence exists, from someone whose business depends on you believing it, that is an assertion wearing the costume.

The test is simple. Can you check?

How this actually happens

Rarely through dishonesty. Almost always through a chain.

A practitioner teaches a course. The course cites research. Attendees take the protocol into practice and repeat the claim, in good faith, on the strength of the teacher’s authority. Some of them go on to teach. The claim propagates, and at every step it sounds better sourced than it is, because everyone in the chain heard it from someone credible.

Then eventually somebody tries to look up the original citation, and it either does not exist, or does not say what it was reported to say, or was a small animal study, or was retracted a decade ago.

Nobody lied. But nobody checked either, and there is a point at which not checking becomes its own kind of dishonesty — particularly when you are charging for the result.

Which brings me to the specific case

I trained in a detoxification protocol taught by a practitioner whose work I respected and, in many areas, still do. The material was densely referenced. It looked rigorous. I taught elements of it and used it with clients.

When I later went back to audit those claims properly, several did not survive. The sweat-as-detoxification-route claim traces back through a lineage rather than to primary evidence. Some of what was presented as established biochemistry was mechanistically wrong. There were drug interaction risks — St John’s wort in particular — that a protocol issued to the public should not carry.

I have written separately about the specific corrections. This article is about something else that happened.

When I went back to check, I couldn’t

My access to the course material was withdrawn.

I want to be careful here, because I do not know the reason, and I am not going to speculate about motive in public. Access to online courses lapses for all sorts of ordinary commercial reasons. I am not alleging anything.

But the consequence is worth stating plainly, because it is the entire point of this article.

I could no longer inspect the source of claims I had repeated to clients.

I could not check whether I had remembered a citation correctly. I could not verify whether a reference said what I thought it said. I could not audit my own past practice, because the material I had learned it from was behind a door I no longer had a key to.

That is not a complaint. It is a design flaw in how this entire field transmits knowledge, and I had walked straight into it.

What I concluded

If the evidence for a claim lives inside a paid course, it is not inspectable, and I should not repeat it as though it were evidence.

That sounds harsh on course providers, and I do not mean it as an attack on paid education. Teaching has value, synthesis has value, and people are entitled to charge for both.

The distinction is this: a course can teach you to interpret evidence, or it can be the evidence. The first is legitimate. The second is a closed loop, and a closed loop is where unchecked claims live longest — because the only people who could challenge them are the people who paid to be taught them.

What I do now

Primary sources, or I don’t say it. If a claim matters enough to give a client, it matters enough to read the original paper. Not the abstract, not the summary in someone’s slide deck — the paper.

Citations that resolve. Everything on this site should carry enough detail — author, journal, year — for you to find it. If it does not, that is a fault in my writing.

The disagreement travels with the finding. When I cite the meniscus trials I cite the methodological critique of them. When I cite a device certification I explain what it does not establish. Evidence with the objections stripped out is marketing.

Publishing corrections rather than quietly editing. Because a claim I have retired is still sitting in documents clients hold, and they cannot know it was retired unless I say so.

And where I am relying on clinical judgement rather than evidence, saying so. A great deal of what I do is pattern recognition across thirty-seven years. That is worth something. It is not the same thing as a trial, and blurring the two is how the field got here.

What to ask any practitioner

Including me:

That last one is the most useful question in the list, and it is the one I would have most struggled to answer five years ago.

The uncomfortable part

I repeated claims I could not verify, to people who paid me, on the authority of someone I trusted. The chain was: I trusted him, he presumably trusted his sources, and the client trusted me.

Trust is not evidence. It is a reasonable basis for many things and a poor basis for clinical claims, and the fact that everyone in the chain was acting in good faith did not make the claims true.

If you cannot check it, it is not evidence. It is somebody’s word — and words are worth exactly what the person behind them is worth, which is never as much as a source you can read yourself.


This article describes my own practice and my own errors. It names no other practitioner, and nothing here should be read as an allegation against anyone.

Five questions to ask any practitioner

Including me. The most useful one is what have you changed your mind about.

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