Further to your point... Not all studies are very good and many are published despite being junk.

Take this one for example.

Randomized Controlled Trial

Greenselect Phytosome as an adjunct to a low-calorie diet for treatment of obesity: a clinical trial

I won't post the link because I don't want to risk breaking any rules, but google that title to have it pop at the top.

It's terrible. They had minimal participants with no verifiable data retrieved from it. Further, it has not been duplicated!