I was trying to think of a kinder, gentler way to get this point across, but sometimes the direct approach is best.
It's patent medicine. If people want to throw away their money on this stuff and feel like it helps them, fine. But the trouble with all of these supplements is that they are completely unregulated by the government.
Nobody tests any of this stuff. Any 'scientific' studies they mention in their marketing materials were conducted or funded by the company, and are therefore garbage. Therefore, there's just no way to know if any of it is safe. And I've read one too many articles about people who need liver transplants, etc., because they took some supplement that was never properly tested on humans.