Sometimes these things work. But the thing is, right, anything you see advertised for money like that, you can find the relevant information online for free. Will it work? Maybe. Maybe not. But if you get the relevant information online how and why something works, you can decide to try the whatever herbs/vitamins/minerals on your own, and if they work, they do, and if they don't, you're not out too much money regardless. Some things are quacky, some things do work.
But generally the things that do work, you can find multiple sources of information about them working, how they work, etc. For example, Rhodiola Rosea is an awesome herb for mental states, and I found graphs showing how exactly how it works, changes in norephrine, epinephrine levels, etc, the person came to the conclusion it acts very much like an SNRI. So to some people, they basically look at herbalism as like, magic, but herbs just contain medicinal things, they contain compounds similar to what you'd get in a regular synthetically made medicine, but in many cases better or having less negative side effects.