While few of the supplements are effective in clinical studies, part of the problem may be that the supplements that are sold don't actually contain any of the primary ingredients. The entire industry is absolutely rotten with pure fraud and the CEOs of the respective companies, as well as everyone else involved, belongs in prison for fraud for long terms.
Republican Senator Orrin Hatch, who has been the guardian angel of these companies in Congress, also deserved some of the blame.
A summary of the findings by the New York attorney general's office's testing:
None of the gingko biloba, Valerian root, St. John's wort, or ginseng in any of the brands at major national retailers contained the ingredients claimed.