@bkruppa There is not a lot of scientific studies in the US. These enzymes have been used for many years in Japan and elsewhere. There are some reviews of the enzymes on websites such as WebMD and Healthline. I did come across an article from a medical journal recommending nattokinase as an anti-thorombolytic - but I'm having a hard time finding it. Here is a review about Serrapeptidase, attached.