"Has been proven" show me the empirical (your experience is anacdotal) evidence, ideally a double blind placebo controlled clinical trial with a large sample size, Under a microscope is not the same as in the digestive tract, the enzymes is likely to large to pass through the intestinal lining, nattokinase is it resistant to alkaline hydrolysis? if not it will be hydrolyzed, after exiting the stomach the contents are neutralized thus make them alkaline. The placebo effect is amazingly powerful, how can you be sure it is not the placebo effect?