The 10,800 FU Nattokinase Dose Rests on a Single Study
A claim is moving through supplement blogs right now that nattokinase at 10,800 FU a day shrinks the plaque in your arteries, sometimes quoted as a reduction of around a third. It is a striking number, and almost no page that repeats it sits next to the larger, better designed trial that found the enzyme did nothing. Put the two side by side and the picture changes.
That contrast is the whole story. One study is a randomized, placebo controlled trial that came back empty. The other is the source of every impressive figure you have seen, and it was not a trial at all in the sense that word usually implies.
What Is Nattokinase?
Nattokinase is an enzyme extracted from natto, the sticky fermented soybean dish eaten for centuries in Japan. It is measured in fibrinolytic units, or FU, which is why supplement doses are written as 2,000 FU or 10,800 FU rather than in milligrams. The unit is a clue to what the enzyme does: it breaks down fibrin, the stringy protein that holds a blood clot together.
That mechanism is the reason nattokinase ever got attention for the heart. If an enzyme can help dissolve fibrin, the thinking goes, maybe it thins the blood, discourages clots, and over time keeps arteries clearer. It is a reasonable hypothesis. The gap between a reasonable hypothesis and a proven treatment is exactly what the human studies are supposed to close, and here they pull hard in opposite directions.
The Science: What the Nattokinase 10,800 FU Dose Actually Tested
Two human studies dominate this topic. One is the kind of study that can actually establish cause and effect, and its result was negative. The other produced all the exciting numbers, and its design cannot support the weight people put on it. Reading them as a pair is the only honest way to answer whether nattokinase does anything for your arteries.
The one randomized trial came back null
The strongest test of nattokinase for arterial health is a proper randomized controlled trial, and it exists.
- The Evidence: The Nattokinase Atherothrombotic Prevention Study (NAPS), run by the atherosclerosis research group at USC, was double blinded and randomized. It enrolled 265 people, median age 65, with no clinical cardiovascular disease, and gave them either 2,000 FU of nattokinase a day or a matching placebo for a median of about three years. Researchers tracked carotid artery intima-media thickness and arterial stiffness with ultrasound every six months. The annualized change in both measures did not differ between the nattokinase group and placebo. There was no effect on blood pressure and no effect on any laboratory measure either. The authors described the result as null.
- Read the study: Nattokinase atherothrombotic prevention study: A randomized controlled trial
Three years is a long time to give a supplement a fair chance, and this is the design built specifically to detect the effect people hope for, with a placebo group to compare against and random assignment to strip out the confounders. It found nothing. When the best available trial on a compound is negative, that is not a footnote. It is the headline.
The viral number comes from a study that was not a trial
Set against that null result is the study that launched the plaque claim, and the difference between the two is not the dose. It is the design.
- The Evidence: A 2022 report in a Frontiers journal followed 1,062 people taking 10,800 FU of nattokinase a day for 12 months and reported that carotid thickness and plaque size fell, with “improvement rates” ranging from 66.5 to 95.4 percent across various measures. Those are the numbers the blogs quote. But the study was retrospective and not placebo controlled: the researchers looked back at people already taking the supplement rather than randomly assigning anyone to take it or a dummy pill. A design like that cannot separate the enzyme from the kind of person who chooses to take an enzyme daily and stick with it. Five of the ten authors were employed by Sungen Bioscience, a nattokinase manufacturer, and one by Sinopharm, and the paper carries a published corrigendum.
- Read the study: Effective management of atherosclerosis progress and hyperlipidemia with nattokinase: A clinical study with 1,062 participants
There is a further detail that undercuts the dose story from inside the same paper. At 3,600 FU a day, the study reported no benefit at all. Only the 10,800 FU arm looked good. So the single dose anyone can point to as effective is the one that appears in the weakest kind of study, funded in part by the people who sell it, while the dose tested in a real randomized trial, 2,000 FU, did nothing over three years. That is the opposite of a convincing dose response.
This is the same trade that runs through the honest corners of the longevity shelf, from why the human case for fisetin still is not in to why lithium orotate is worth waiting on rather than guessing at. A compelling mechanism and a viral statistic are not the same thing as a result you can trust.
A Practical Guide: How to Use It
If you have read this far and still want to try nattokinase, the practical picture is thin. There is no dose with solid human evidence behind it for arterial plaque. The 2,000 FU on most capsules, including the product here, is the amount that failed to move anything in the NAPS trial. The 10,800 FU that looked impressive comes only from a retrospective study that cannot prove cause and effect. Chasing the higher number means taking roughly five times the dose on the strength of the weaker evidence, which is backwards.
Nattokinase does have a plausible short term action on clotting factors, and some people take it for general circulatory support rather than plaque reduction. If that is your reasoning, keep the expectation modest and the dose conservative, take it with food, and understand you are acting on mechanism rather than on a proven outcome. Do not treat it as a substitute for the things that genuinely lower cardiovascular risk, which remain unglamorous: blood pressure control, not smoking, exercise, and where indicated, a statin your doctor has prescribed.
Safety and Advice
The one property nattokinase clearly has is the one that demands caution. Because it breaks down fibrin, it can act as a blood thinner, and that is not a benign feature to stack casually. Anyone taking an anticoagulant such as warfarin, an antiplatelet drug, or even regular aspirin should not add nattokinase without medical advice, since the effects can combine. It should be stopped well before any surgery or dental procedure, and it is not appropriate during pregnancy or breastfeeding. People with a bleeding disorder should avoid it outright.
The higher the dose, the more these warnings apply, which is another reason the 10,800 FU figure deserves skepticism rather than enthusiasm. Natto itself, the fermented food, is also rich in vitamin K2, though purified nattokinase supplements are typically low in K, so the interaction that matters most is the fibrin one, not vitamin K. If you are on any medication that affects bleeding, this is a conversation to have with a clinician before you start, not after.
The Bottom Line
The evidence does not support buying nattokinase to clear arterial plaque. The one randomized, placebo controlled trial gave 2,000 FU a day for three years and found no effect on artery thickness, stiffness, blood pressure, or blood work. The famous plaque reduction and the 10,800 FU dose behind it come from a single retrospective study that was not placebo controlled and was part funded by a manufacturer, and even that study found a lower dose useless.
If your goal is healthier arteries, put your effort where the trials actually point. Nattokinase is an interesting enzyme with a real mechanism and a genuinely negative result at the dose that was properly tested, and honesty about that gap is worth more than another repost of a number that will not survive a look at its source.
This article is for educational purposes only and is not medical advice. Supplements can interact with medications and health conditions, so talk to a qualified healthcare provider before starting anything new.
Common questions
Does nattokinase actually clear arterial plaque?
The best evidence says no. The one randomized, placebo controlled trial, NAPS, gave 2,000 FU a day for about three years and found no change in carotid artery thickness or stiffness. The widely shared claim that it shrinks plaque comes from a retrospective study that was not placebo controlled and had authors employed by a nattokinase maker.
Is the 10,800 FU nattokinase dose based on good evidence?
It rests on a single retrospective study of 1,062 people, not a randomized trial. That study reported large improvements, but its design cannot rule out that the people taking nattokinase were simply healthier or better cared for to begin with. No randomized trial has tested 10,800 FU a day.
Is a high dose of nattokinase safe?
Nattokinase breaks down fibrin, so it has a blood thinning effect. That makes it risky to combine with anticoagulants like warfarin, antiplatelet drugs, or aspirin, and it should be stopped before surgery. The higher the dose, the more that matters. Talk to a doctor before taking it, especially on any blood thinner.
How much nattokinase did the research use?
The null randomized trial used 2,000 FU a day. The retrospective study behind the plaque claim used 10,800 FU a day, and the same study reported that 3,600 FU a day did nothing. So the only dose with a positive result is also the one with the weakest study design behind it.