A certificate of analysis reports the results of defined analytical tests performed on a defined batch: identity, purity by a stated method, water content, endotoxin or sterility where applicable, and so on.
What it does not do is establish that a compound is safe or effective for a person to use. Those are clinical and regulatory questions answered by trials and by a regulator's assessment, not by an analytical laboratory.
A COA is also only as meaningful as its chain of custody. It should tie to a specific batch or lot number that is traceable on the physical product, and ideally to an independent laboratory. A generic, undated or unlinked document tells you very little.
This article is educational and general in nature. It is not medical advice and does not describe any treatment, dose or protocol. Speak to a registered healthcare professional about your individual circumstances.