Herb & supplement monograph

Nattokinase Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Nattokinase interacts with medications. The heart of this page is the interaction list — every drug Nattokinase is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Nattokinase is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Nattokinase Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Nattokinase drug interaction appears low for most people, with the clear exception of blood thinners and blood pressure medicines. None of the listed interactions are rated major, and the supporting evidence is limited, resting mostly on theory and a single reported case rather than controlled human studies.

Interactions deserving the most attention

The concern that stands out most is with anticoagulant and antiplatelet drugs. Nattokinase itself can thin the blood and break down clots, and there is one report of a serious brain bleed in a person who added it to aspirin. The other concern is with blood pressure medications, since some research suggests nattokinase may lower blood pressure, so combining them could theoretically drop it too far. Both effects touch closely monitored areas, bleeding risk and blood pressure, which is why we take them seriously despite thin evidence.

What the rest of the list means

The long list of medications here can look alarming, but it really reflects just two themes, bleeding and blood pressure, spread across hundreds of individual drugs. Most of the concern is theoretical, based on what nattokinase does on its own, and has not been confirmed as harmful in well-controlled human studies.

Check your medications against Nattokinase

Based on HelloPharmacist’s Nattokinase interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Nattokinase

289 medications have a known interaction with Nattokinase, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Nattokinase using our pharmacist-reviewed interaction data.

AI summaries are generated from our Nattokinase interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Nattokinase combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Nattokinase affects

Every type of medication (drug category) Nattokinase is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 2 drug categories Nattokinase interacts with

Anticoagulant/antiplatelet DrugsAntihypertensive Drugs

Anticoagulant/Antiplatelet Drugs

Nattokinase might increase the risk of bleeding when used with anticoagulant/antiplatelet drugs.
Nattokinase has thrombolytic and anticoagulant effects. There is a case report of intracranial hemorrhage in a patient who added nattokinase to aspirin therapy.

Likelihood Possible Evidence D

Antihypertensive Drugs

Theoretically, nattokinase might increase the risk of hypotension when used with antihypertensive drugs.
Some clinical research suggests that nattokinase may reduce systolic and diastolic blood pressure.

Likelihood Possible Evidence D

Monograph

Nattokinase: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Nattokinase is an enzyme from the fermented soybean food natto that may have mild blood-thinning and blood-flow effects. Some small studies hint at benefits for blood pressure and circulation, but the evidence is limited and more research is needed. Because it can affect clotting, talk to your pharmacist or doctor before trying it, especially if you take medicines or have a bleeding risk.

Part used: Enzyme extracted from natto (fermented soybeans)
Common forms: Capsules, tablets, softgels

People commonly use it for

Heart and circulatory health
Blood clot prevention
High blood pressure
Improving blood flow
Cholesterol support

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Generally tolerated short-term, but its blood-thinning effect means caution for people with bleeding risk.

PregnancyInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

Nattokinase is an enzyme that comes from a traditional Japanese food called natto. Natto is made by fermenting soybeans with a bacteria called Bacillus subtilis. The fermentation process produces the enzyme, which is then concentrated and sold as a dietary supplement.

People most often take nattokinase in capsule or tablet form for heart and circulation support. While natto itself has been eaten in Japan for centuries, the purified enzyme supplement is a more modern product marketed for cardiovascular health.

How it works

Nattokinase is a fibrinolytic enzyme, which means it can help break down a protein called fibrin. Fibrin is part of what forms blood clots, so by breaking it down, nattokinase is thought to help dissolve clots and keep blood flowing smoothly.

Researchers also believe it may have mild effects on blood pressure and blood vessel function. Much of what we know about how it works comes from laboratory and animal studies, and the exact effects in the human body are not fully understood.

Effectiveness

Does Nattokinase work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 16 uses evaluated

16 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

For Nattokinase, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 16 conditions — evidence insufficient to rate

Insufficient Reliable Evidence To Rate Angina