If you buy controlled substances online you're always going to be in some kind of legal danger.
Any source that gets busted, the bargaining chips they have are their upstream suppliers and methods and their downstream distribution destinations and methods. If I were to use a source and knew that source got busted, I would assume details of my transactions were in the hands of LE.
That being said, after all these years and all the major busts that we've seen, I don't think I have ever heard of someone getting busted for having previously bought personal amounts of gear at some point in the past from the busted source. "Hey, six months ago, according to this excel file, you bought 3 vials of testosterone from Joeys House of Biceps, we're here to search your house" IMO that is a low probability outcome and can't recall something like that ever happening. (I am sure someone will now link to a story where that exact scenario happened)
If you were buying distribution amounts, or if you bought narcotics, opioids, amphetamines, if you're on parole and subject to random drug tests, if you have previous convictions...that might be a different story.
