The citation rule.
We do not state a thing about biology that is not traceable to a study, a meta-analysis, or a regulatory document. This is not a style preference. It is the operating constraint. If we cannot cite a claim, we do not make it.
When the evidence is absent or inconclusive, we say so plainly: “the research on this is limited,” or “this has not been adequately studied in the relevant population.” We treat “we do not know this yet” as a complete and acceptable answer.
Where a compound or practice is discussed speculatively, the confidence label is Speculative and the language is conditional throughout: “clinical studies suggest,” “animal models indicate,” “discuss with your physician before considering.”