How we prepare the supplement encyclopedia
Our supplement encyclopedia explains what is known about ingredients and their forms, where the evidence comes from and what remains uncertain. It is intended for everyday questions, such as sleep, recovery, exercise and dietary nutrient intake. It is not a guide to treating diagnosed diseases or a substitute for individual medical advice.
Updated: · Pillintrip editorial team
Starting with the right ingredient
Before interpreting an effect, we identify the substance and the form used in a source. Different salts, chemical forms and preparations may not have the same properties or the same evidence. When a study does not specify a form, we do not treat it as proof about a particular form. A mixture is considered as the mixture studied: its result cannot automatically be attributed to one ingredient.
Finding and assessing evidence
We use research in people, reviews and relevant authoritative references, as appropriate to the question. Laboratory and animal findings can help explain a hypothesis, but they do not by themselves establish a benefit in people. We look at the original source and its identity, including the actual title and link. The presence of a paper in a bibliography does not mean it answers every question on the page.
For a reported result, we consider who participated, the form and dose or dose basis, what it was compared with, how long it was used and what was measured. We distinguish results in people with a diagnosed condition from evidence relevant to an everyday goal; we do not simply transfer one to the other. A change in a laboratory marker is also not automatically a meaningful change in how a person feels or functions.
We consider conflicting and negative findings as well as positive ones. Several publications may describe the same trial, and a review may include trials also cited separately; those are not automatically independent studies. Differences in participants, methods and measurements can explain why results do not agree. Our pages provide a descriptive synthesis of the evidence considered; they do not claim that we performed a new meta-analysis or a complete systematic review for every topic.
We frame each question before interpreting findings. Reviews can help identify relevant trials and their limitations; we also consider suitable primary studies, including negative and conflicting findings and newer studies when found. Search coverage and available full text vary, so references and limitations on an individual page matter.
We distinguish the number of reports from the number of independent trials. When several reports share participants or a control group, counting them separately could exaggerate the evidence. If studies differ too much in their questions or measurements for a sound combination, we explain them descriptively rather than force a numerical result.
Understanding confidence
When an outcome has been assessed, the four levels describe confidence in the evidence for that particular comparison: 1/4 very low, 2/4 low, 3/4 moderate and 4/4 high. The question identifies the people, ingredient and form, dose, comparator, outcome and time. A level applies to that question; it is not a universal score for the ingredient.
We consider five aspects: risk of bias in the studies, inconsistency between independent results, indirectness for the question, imprecision, and possible missing or selectively reported results. A well-designed randomised comparison can provide stronger evidence for an effect than uncontrolled before-and-after observations. Observational findings can identify associations or safety signals, but do not by themselves establish cause.
Not assessed, shown without a number and with a reason, is different from evidence of no effect. For example, a decisive source may be unavailable or an important limitation unresolved. A lack of a clear difference does not prove that an effect is absent. New suitable studies, better access to existing reports, or corrections to study identity or methods can change the assessment.
Confidence is not the size or importance of a benefit, a recommended dose, proof of safety, or a prediction of an individual's response. These questions are considered separately. Our working approach draws on established principles of evidence assessment; it is not a claim of formal GRADE certification.
Doses, food and safety
A dose used in a study is not necessarily a recommended intake. Dietary reference values and upper limits answer different questions, and may differ by age, country or authority. Food composition figures describe a particular food and measurement basis. An amount in food is not automatically equivalent to a supplement dose used in a study. When reliable detail is unavailable, an omitted figure or section does not prove that no relevant food or evidence exists.
Safety depends on the person, the product and how it is used. Interactions, contraindications, pregnancy, illness and other medicines can matter. Check the product information and discuss use with a doctor or pharmacist, particularly if you take medicines or have a health condition. Natural origin does not guarantee safety.
Preparation, translations and updates
Automated tools may assist with finding and organising material, drafting and translation. They do not provide clinical approval. A named or assigned reviewer is not evidence that a personal review has been completed; where a completed professional review is recorded, its actual details should be shown. Translations are checked separately for meaning, including negatives, numbers, dose, form, population and country. The date on this page is its update date; it does not claim a research search cutoff or a professional review date.
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