When it comes to supplements, you and I are guinea pigs, unlike with real drugs, where lab rats (and sometimes guinea pigs) are the guinea pigs. Vox explains why in a good article (read it here) today:
To remove a supplement from the market, the FDA first has to prove that it’s not safe. This is basically the opposite of how pharmaceuticals are regulated, where drug makers need to prove their medicines are safe and effective through high-quality scientific studies before they reach consumers.
Over the past few decades, fierce lobbying efforts by industry groups, coupled with work by a few influential lawmakers, have pushed back bills that would bring supplement regulation closer in line with pharmaceutical regulation. The Dietary Supplement Health and Education Act (passed in 1994) … allowed supplement manufacturers to test their products on a voluntary basis before selling them and blocked the FDA from regulating them unless there was evidence of harm.
Supplements and “natural” remedies are a multi-billion-dollar industry in this country, so it’s no surprise that they (like all businesses) try to avoid government regulation. Big Herbal can be just as greedy as Big Pharma.