Has anyone tried nattokinase?

I take nattokinase and serrapeptase. When I took serrapeptase alone, I noticed sinuses cleared easier.
Nattokinase seemed to improve my circulation. The reason I think this is that my feet are no longer cold. I also feel better in the sense that my legs don't hurt anymore.
My family has a history of MIs, CVAs, and other less life threatening cardiovascular issues. It really has helped me feel well overall.

Interesting! Iḿ greatly hoping that indeed, that GI upset post-massage was a confirmatory Herxheimer reaction. And perhaps the input of that natto/serra combination, on board for the preceding 3 weeks, helped to make that massage even more effective than it might otherwise have been. I do like the idea of multiple healing therapies producing exponential benefits. I expect to stay on serrapeptase indefinitely if it produces the breakthrough that I sometimes feel is beginning, but long-term use of these proteolytic enzymes, like high dosing of these enzymes, has not yet been carefully studied. . .Needless to say, this does not deter me, at the moment. The topical (intransal spray) drugs I was pressured to stay on in the early days of my long COVID definitely did some damage from which I am still trying to recover, and yet the medical literature is LOADED with ¨proofs¨ that using those drugs forever is perfectly safe for everyone. Ugh . . .

I take nattokinase and serrapeptase. When I took serrapeptase alone, I noticed sinuses cleared easier.
Nattokinase seemed to improve my circulation. The reason I think this is that my feet are no longer cold. I also feel better in the sense that my legs don't hurt anymore.
My family has a history of MIs, CVAs, and other less life threatening cardiovascular issues. It really has helped me feel well overall.

Years before the pandemic, I made my own natto using frozen natto as a starter. Natto has K1, nattokinase, that thins the blood which helps with circulation by reducing the micro clots. The improved circulation helps with getting oxygen to our tissue / muscles. Natto also has K2 that is important in getting calcium out of the arteries and to our bones.
When I had Long Covid, I was too ill to make natto, so I tried nattokinase in capsules. That did nothing for me.
Natto is fermented at 104 degrees. Nattokinase is heat sensitive. To dry it to a powder in order to put it in capsules, they have to use heat. That damages the nattokinase.
It is difficult to find fresh natto in the US, but I did find NYrture. I did order from them and it did seem to help when I had it, but do to the expense I did not have it everyday, maybe twice a week, and I seemed to have a “roller coaster” pattern of symptoms improving when I had natto and “taking a dive” when I didn’t.
I am back to making natto and I use fresh natto as a starter from NYrture in Brooklyn. They ship by air in ice packs. The owner has a doctorate in micro biology. Using that as a starter, I do get “nice threads”, which is the nattokinase. I would be glad to advise on making natto if anyone has an interest. You can start looking into it by searching for “Natto Dad” on YouTube. He got me going and I have made a couple of adjustments.
Each morning as first food, I have natto with kimchi, the Korean fermented cabbage. Kimchi can be found in most major groceries and has health benefits, if you get the refrigerated variety. The unrefrigerated on the shelf variety has no benefits.
The natto helped, but my Long Covid symptoms have dramatically improved since I started taking L-Arginine with vitamin C that helps our bodies to produce nitric oxide that improves oxygen transportation to our tissues. If our tissues do not get sufficient oxygen, we will experience fatigue, muscle aches, breathing problems and brain fog.
At the beginning of this year, I saw an Italian study that used L-Arginine and vitamin C with success in lowering LC symptoms, so I thought I would try it. I started with 1 gram L-Arginine with vitamin C and I found that I no longer had PEM. I added L-Citrulline 3g, with vitamin C, that turns into L-Arginine. Total L-Arginine and L-Citrulline should not exceed 9 grams per day. I went up to 6 to 8.25 grams per day. As my symptoms lessoned, I reduced the dosage to 3 grams of L-Citrulline per day. I am also taking L-Carnitine and Creatine.
Most vitamin C capsules are too strong. I did have stomach problems taking vitamin C twice a day at 500mg per dose, or 1000 mg per day. I did find a vitamin C powder and I take 1/8 tsp, around 100mg C, with 3g L-Citrulline. At that dosage, my LC symptoms are dramatically reduced and my stomach is okay.
I also focus on having foods that will assist on creating nitric oxide, such as beets, celery, arugula, walnuts, cocoa and honey. Search “nitric oxide foods” and you will find many. I make up recipes like celery sticks with nut butter and a slice of orange (remember the C). I have cocoa and honey with almond milk in the morning. Beets are a great choice, but I restrict them to ½ cup every other day to avoid too many oxalates that could cause kidney stones. The liquid in the beets (beet juice) is a good source.
Here is a link to the Italian study:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9295384/