A COA confirms content, not necessarily a ratio
A certificate of analysis primarily confirms what’s in the vial: purity and mg content. It doesn’t always include a recommended reconstitution ratio, since that’s a usage suggestion rather than a lab measurement. Some suppliers add one anyway as a courtesy; not all do.
Why a supplier-suggested ratio is different from a COA figure
A COA’s mg content is a measured fact about that specific batch. A suggested reconstitution ratio, if included, is just one reasonable option among several, chosen for convenience rather than being the only correct answer.
What good supplementary documentation looks like
Separate from the COA itself, a useful reconstitution reference states the exact vial size it applies to, a suggested water volume, and the resulting concentration, clearly distinguished from the lab-verified mg content.
Red flags in how ratios are presented
A ratio presented as if it were a lab-verified requirement, rather than a suggested convenience option, misrepresents what a reconstitution ratio actually is. Any ratio should be treated as adjustable to your own needs, not a fixed instruction from the manufacturer.
Using this to sanity-check a listing
A listing that clearly separates its COA-verified content from its suggested-but-optional reconstitution guidance is demonstrating a more accurate, transparent approach than one that blends the two together as if they carry equal authority.