I recommend only products I have personally researched and muscle tested. Based on all of that, whenever possible I use products from Nature's Sunshine. I consistently find that people will test for far more capsules of other brands of the same herb than the same product from Nature's Sunshine. They are the only supplement company that tests every batch of every raw material using gas chromatography, which is the only way, for example, to differentiate Golden Seal, which is very expensive, from another, less expensive herb that does not have the same properties. They are also the only company that tests for Beta radiation, which contaminated most of the world's golden seal supply after fallout from Chernobyl drifted west over Scandinavia.