Earlier quoted context omitted.
> Most supplements are garbage. Since they don't actually work, most people would never know if you replaced their magnesium or calcium supplement with chalk. Whether or not that's true, if you replaced someone's magnesium supplement with viagra , you could seriously hurt them. >> FDA confirmed through laboratory analyses that the [...] products, purchased on www.amazon.com, contained [...] the active ingredients in…
holy crap, that’s insane. You don’t just accidentally add sildenafil or tadalafil to your supplements. Unless the FDA is misidentifying compounds present in the herbs in these supplements, which seems unlikely but I’m no pharmacology expert.
It's a better regulated industry now, but with the explosion in supplement popularity over the last decade I doubt there is an easy way to test and punish all manufacturers. If you look at the list of supplements included in that warning letter, they have classic nonsensical names that Chinese companies are known for (WeFun, Genergy, etc). None are on www.amazon.com anymore, but hundreds of other supplements show up with absolutely no way of telling whether any of them are clean (e.g. "Endurance 2Nite").