How EBL works
The whole method on one page. Each section links to the page that holds the detail.
A letter for one use, not for a product
EBL grades the human evidence for one named use at a time. Creatine can hold an A for strength with resistance training and a D for bone density, because those are different questions with different trials. The letter describes the evidence, not the bottle, the brand or the ingredient’s worth. Every supplement and every graded use →
The four letters
- AReplicated The same finding reproduced by a separate research group. A result seen once can be chance or bias; a replicated one is harder to explain away.Replicated trials on a qualifying endpoint The outcome a trial measures to decide whether the treatment worked, such as heart attacks, blood pressure or a symptom score.
- BSupportedA good trial, backed by more
- CLimitedSmall, mixed or unreplicated trials
- DNot shownNo human trial shows benefit
The full definitions, with what each one requires: how grades work →
What counts as evidence
Only randomized trials in people can earn a letter. Animal studies, test-tube work and testimonials never raise one. A grade also depends on what the trial measured: a hard outcome or an instrument-measured function can reach A, while a lab marker or a self-reported score stops at B however good the trial. An A needs the result repeated by independent research groups, and a trial needs more than 30 participants before it can move a grade.
Where the evidence is missing
A D means no human trial shows benefit. It is reached two ways: no qualifying trial has been run (Route 1 No human randomized trial has been run, so the record rests on animal or mechanistic evidence only. One of the two routes to the lowest letter on EBL's scale.), or trials were run and found nothing (Route 2 Human randomized trials have been run and did not show benefit on the stated outcome. One of the two routes to the lowest letter on EBL's scale.). Many records show the search behind the grade: the PubMed query, the date it was run, how many papers it returned and why the rest were left out, so the absence of evidence can be checked as well as its presence.
Money
EBL earns $0 on every supplement it grades, so no supplement grade can be suspected of being bought. EBL does earn commissions on some devices and tests, which carry no letter of their own; where one belongs to a graded therapy, the relationship is disclosed beside that letter, and no company can approve, buy or raise a grade. Every paid relationship, named →
Who decides, and how a grade changes
The editor applies the written definitions; the build checks every letter against them and stops the site from publishing when one breaks a rule. Grades move down as well as up. Every change is logged with its date, its reason and the trial that triggered it. The Evidence Log → · Editorial standards →
What EBL does not do
EBL grades evidence. It does not tell you what to take, what to stop, or what to avoid. It shows what the human trials found, so the decision can be made with a clinician who knows the person. Educational use only, not medical advice.