They are sold as dietary supplements, and are thus not regulated by the FDA.
While this may be attractive to some, such as those who hate "Big Pharma", it actually means that the potency of the supplements can vary widely between production runs, batches, containers, and even individual doses. It also means that there may be some non-herbal substances that were introduced during the cultivation process - substances like pesticides, herbicides, chemical fertilizers, and even industrial waste (ie, Adhesives, Paints, Petroleum Distillates, Solvents, et cetera) or common metals (ie, Antimony, Arsenic, Chromium, Lead, Selenium, et cetera).
If there is also no record of clinical testing, such as one would use to determine the minimum effective dose, the minimum toxic dose, and synergy with other substances (ie, Drugs, Foods, et cetera), then you are taking on an unknown risk without recourse to restitution.
If you want to spend your money on a "Good Faith" product - one that offers only subjective testimony to support claims of efficacy - then that is your choice.
Personally, I'd rather spend my money on something that has been proven to actually work.