Nattokinase and Blood Pressure: What Human Trials Actually Show
Can nattokinase lower blood pressure? Human research offers a mixed picture. Here's what randomized trials and a meta-analysis actually show.
If you've been researching nattokinase and blood pressure, you've probably come across claims that this enzyme may support cardiovascular health.
But what do human studies actually show?
The answer is more nuanced than many supplement articles suggest.
Some smaller randomized trials have reported modest reductions in blood pressure among people taking nattokinase. However, a larger, longer-term randomized trial did not find a significant effect on blood pressure.
So, let's look at the evidence.
What is nattokinase?
Nattokinase is an enzyme produced during the fermentation of soybeans to make natto, a traditional Japanese food.
Natto has been consumed in Japan for centuries and is naturally rich in nattokinase.
Because of its effects on certain processes involved in blood clotting and circulation, nattokinase has attracted interest from researchers studying cardiovascular health.
However, evidence of a biological effect does not automatically mean that nattokinase can prevent or treat cardiovascular disease or high blood pressure.
That's where human clinical research becomes important.
What does the research say about blood pressure?
A meta-analysis examining 6 randomized controlled trials involving 546 participants reported reductions in both systolic and diastolic blood pressure among people taking nattokinase.
These findings are interesting because they suggest that nattokinase may have some effect on blood-pressure measurements.
But there are important limitations.
The individual studies were relatively small, and differences in study design, participant characteristics and supplementation protocols make it difficult to draw a definitive conclusion.
Then came a larger 3-year trial
A longer-term randomized controlled trial provides an important counterpoint.
The study followed 265 generally healthy, low-risk adults for 3 years and found no significant effect of nattokinase supplementation on blood pressure.
This is important because longer studies can provide a different perspective from shorter, smaller trials.
Taken together, the evidence doesn't give us a simple "yes" or "no."
So, can nattokinase lower blood pressure?
The current human evidence is mixed.
Some randomized trials and a meta-analysis have reported modest reductions in blood pressure, while a larger 3-year randomized trial found no significant blood-pressure benefit.
More high-quality research is needed to understand whether nattokinase has a meaningful and consistent effect on blood pressure, and whether any observed changes translate into meaningful cardiovascular outcomes.
What about natto?
It's also worth distinguishing between nattokinase as an isolated enzyme and natto as a whole food.
Natto contains nattokinase alongside protein, fiber, vitamins, minerals and other compounds produced during fermentation.
So, research on nattokinase supplements shouldn't automatically be interpreted as evidence that eating natto—or consuming a particular nattokinase product—will produce the same effect.
Should nattokinase replace blood-pressure medication?
No.
If you have high blood pressure or are taking medication to control your blood pressure, nattokinase should not be used as a replacement for prescribed treatment.
Blood pressure is an important cardiovascular risk factor, and decisions about starting, stopping or changing medication should be made with your healthcare professional.
Nattokinase may be an interesting area of nutritional research, but the current evidence isn't strong enough to position it as a treatment for hypertension.
The takeaway
Research into nattokinase and blood pressure is promising but far from conclusive.
A meta-analysis of six randomized trials found modest reductions in blood pressure, while a 3-year randomized trial involving 265 adults found no significant effect.
For now, the most accurate way to describe nattokinase is as a food-derived compound being studied for potential cardiovascular and circulatory effects—not as a treatment for high blood pressure.
At Living Alpha, we believe in looking at the research carefully and keeping the conversation around wellness grounded in evidence.
