I have stopped trying to warn people. They either get angry at you or look at you like you're crazy. It's like heroin. You can warn people around you not to try it, but if they want to, they will. You cannot help people who aren't willing to look into it themselves. If they will let anyone in a white lab coat inject whatever into them, then there are many other ill-advised decisions they will make in their lives and you can't stop them all. Just gotta look after yourself.