Safe is a term not to be used with any PED's. All PED's have their risks. The best thing to do though is research and figure out what risks certain things have and if you are willing to work with those risks. Things can go sideways very quickly, so it is best to tiptoe into the water than jump into the deep end.
Make sure anything you are taking has some kind of documentation to back up what it is supposed to do and list possible risks. Ideally you want something that has had human trials published on and if not human at least lab rat tests, otherwise you are the lab rat and the moment you take it you now run the risk of sides popping up years down the road.