I started taking this after researching the benefits. This brand seems to be pure, no fillers, and regarded as high quality. I have poor circulation and varicose veins with pooling of blood in my feet some days. I’m active, still fairly young (51) and for the most part healthy, but I do have EDS and I think that may play a part in more than a bad collagen gene. Anyways, since taking these, blood has not pooled in my feet, they haven’t swelled or been painful. If this is a sign that natto works, that’s fine by me. I will continue to take it, unless there’s no other improvements or I have negative side effects.