Yep, double blind studies. The core of scientific research. And, yes a single population test regime can be done more quickly, and is used as an indicator to initiate the more complex, and costly double blind testing. But there are a lot of potential drugs, which show enough promise to enter the double blind testing, and then don’t pan out. And, since the standards of safety were relaxed twenty odd years ago, there have been quite a few which made it into actual approved general release, which were then found to unnecessarily dangerous. Personally, I don’t like to take any drug, which hasn’t been around long enough to go off patent, and go generic. There have been several diabetes wonder drugs, approved, which after a year or so in wide spread use have been pulled, because they quadrupled the rate of heart disease, tripled the rate of kidney complications, caused pancreatic cancer, or caused the kidneys to secrete the glucose so fast that patients got yeast infections which couldn’t be controlled. Doctors aren’t generally the most intelligent folks, they just memorize well. So, you need to be informed and an active member of your medical care team.