I have had poor circulation my whole life, especially cold hands and feet, which got worse when I hit my 60s. I started on 1 capsule of nattokinase at dinnertime and rapidly felt more warmth in my hands. Then about a week later I had more warmth in my feet. This improvement to my extremities is remarkable to me because I have tried other supplements to improve circulation like horse chestnut but they absolutely did not help.
I will continue to take 1 capsule of 2,000 a day. Only side effect is that I tend to bruise more easily but that's okay.
Nattokinase is an excellent blood thinner. It is worth reading up on and studying. I have read that older adults that means like sixty, should take Pine Bark or Boron or another supplement that strengthens blood vessels when using nattokinase long lengths. It is said that this rule actually applies when taking any blood thinner such as aspirin etc.
Nattokinase has helped me with circulation problems. I do use Pine bark also.