Evidence Briefs

What the Research Shows

The question, the trials that tested it, and the point where the evidence stops.

Every brief here answers one question by going to the randomized trials and meta-analyses rather than to the marketing. Each one states what was measured, in how many people, and with what certainty, and each one says plainly where the evidence runs out. That last part is the reason these exist. A finding reported without its limits is how a modest effect becomes a confident claim, and how a withdrawn guideline threshold stays in circulation for years after the body that proposed it stepped back.

Supplements under scrutiny

Compounds with enough randomized trials behind them to say something specific, which is a smaller list than the supplement aisle implies.

Creatine and Cognition

Sixteen trials. Memory and processing speed moved. Overall cognitive function and executive function did not.

Ashwagandha and Stress

Twenty-two trials pointing one way, and effect sizes large enough to warrant reading the methods.

Berberine and Metformin

Two compounds on the same switch, and one changes how you process medication.

Selenium and Hashimoto's

Thirty-five studies. Antibodies and TSH fell. The thyroid hormones themselves did not.

Probiotics and IBS

Forty trials, a real symptom effect, and a method that says the question is unfinished.

Practices worth getting right

Where the useful answer is not whether to do it but when, and the difference is measurable.

Resistance Training and Ageing

The strongest evidence in this directory, and it is not a supplement.

Cold Plunge and Muscle Growth

Excellent for recovery, and there is one situation where that is the problem.

Intermittent Fasting and Weight

Ninety-nine trials, and a result smaller than either side of the argument claims.

Sauna and Cardiovascular Health

A twenty-year Finnish cohort, a clean dose-response, and one thing it cannot show.

Markers and what they predict

Where a number is worth measuring, where it is worth treating, and why those are not the same question.

ApoB Versus LDL Cholesterol

Nine discordance studies out of nine, and the group most likely to be reassured wrongly.

Fasting Insulin and Early Detection

The marker that moves years first, and why no standard panel runs it.

Homocysteine and Heart Disease

A textbook case of a strong association that did not survive being tested.

Iron and Fatigue Without Anaemia

The gap between an empty tank and a low blood count, and the trials that went looking.

Vitamin D and the 2024 Guideline Change

The threshold everyone quotes was withdrawn by the body that created it.

Every brief cites real, verifiable studies with linked PubMed IDs, and reports the negative findings alongside the positive ones. Where a widely repeated claim turns out to rest on very little, that is stated as plainly as the claims that hold up. These pages answer what the evidence says in general; a paid research report answers what it means for one person, their labs and their medication list.

14 pages published so far. More are being added.

Before you stack the next thing

Occasional notes on what the research supports, what interacts with what, and the questions worth asking your prescriber.