I think anytime you use some powder or other drug/supplement you purchased online, you have to accept it’s a gamble. I shudder to think of the crap I must have inadvertently ingested over the decades. Sadly, it’s a consequence you have to accept if you want to use any synthetic mind altering drug, unless you have your own personal GC, NMR, or whatever. That said, I think most of the research chemicals I acquired over the 90s to late 2010s were probably reasonably pure. In the present day, I wouldn’t trust anything I could acquire, except maybe nootropics or peptides. It’s what I most appreciated during the golden age of research chemicals. For the most part, you got what you ordered. Alas, those days are gone forever…