Every intervention discussed on this site carries a grade. The system is published here so that any grade can be checked against the reasoning behind it, and disputed if it looks wrong.
Good evidence and/or guideline-supported.
Human evidence exists; important questions remain.
Small, inconsistent, or of uncertain clinical relevance.
Insufficient evidence for routine clinical use.
No convincing evidence of meaningful benefit.
The rules
Popularity never raises a grade. A claim believed by ten million men with no trial behind it is Limited.
Mechanism never raises a grade above Experimental on its own. A plausible biological pathway is a reason to run a study, not a reason to act.
Grades attach to claims, not substances. Zinc is Established for correcting a documented deficiency and Unsupported for raising testosterone in men who are already replete. Both grades appear on the same entry, because they are different claims.
Grade changes are logged with a date and a reason. When a new trial moves something, the change is visible rather than silent.
What sits behind a grade
Sources are weighted in this order, and where they conflict the higher tier wins unless there is a stated reason: current professional guidelines and society statements; systematic reviews and meta-analyses; randomized controlled trials; large prospective cohorts; high-quality observational studies; and mechanistic research, which is used to explain rather than to support a clinical claim.
Testimonials, uncontrolled case series presented as efficacy, animal studies extrapolated to humans, influencer claims and supplement marketing are not treated as clinical evidence at any tier.
Commercial testosterone platforms are read to understand what patients are being told and what claims need addressing. They are never cited as evidence. Where a commercial claim is discussed, the page distinguishes explicitly between what clinics market and what the evidence supports.
Numbers
Figures are quoted exactly or not at all. Where a precise number could not be verified against a primary source, the page states the direction of effect and says that the magnitude is unverified — rather than reproducing a figure that is circulating without a traceable origin. Confidence intervals are given wherever a point estimate is doing persuasive work.
This occasionally means a page declines to answer a question that other sites answer confidently. That is the intended behaviour.
Review
Guideline-dependent pages are reviewed quarterly. Physiology pages are reviewed annually. A new guideline, an FDA action, or a major trial publication triggers immediate review of every page tagged to that topic. Each page carries a visible review date.