There's this brand named Nootropicsdepot whose advertising, as well as the owner's reddit commentary, has convinced me they are tip of the top in quality LOL (maybe I'm naive). Anyway they say they have tested tons and tons of brands of supplements over the years. Fitness community related: when everyone was selling "turkesterone" they said not a single one product on the market was genuine, it didn't exist, a few guys we here regard as legit still continue to sell it. Regarding brands, they say only one single company has passed every single test they have ever done: THORNE. This includes otherwise high quality brands like NOW Foods. I wish ND was sold here in the EU, they have a berberine/silymarin complex product. And Thorne is of course always the most expensive LOL.