What does "third-party tested" actually mean?

It means an independent lab — not the brand — verified that the product contains what the label claims and is free of banned substances or contaminants. It comes in tiers: a brand publishing its own lab results is good; ongoing certification programs like NSF Certified for Sport and Informed Sport, which batch-test and audit, are stronger. The catch is that "lab tested" on a label can mean almost nothing without a name and a certificate behind it. We state each product's status plainly — certified, self-published, or not published — and treat "not published" as a real mark against, not a neutral blank.