Health Benefits of Nattokinase

Nattokinase (NK) is a proteolytic (protein digesting) enzyme extracted from the popular Japanese food natto.

It is believed to be very useful in reducing heart disease by thinning the blood. This is reason for taking a low dose Aspirin daily to reduce the risk of heart attack for people at risk for one.

Those practicing in the alternative medicine and holistic health regard this enzyme as a "clot-buster". They commonly prescribe it to their patients who have suffered from heart attacks.

It was first discovered in the 1980's by Dr. Hiroyuki Sumi, a University of Chicago researcher.

Other names that nattokinase is known as include NK, fermented soybeans and natto extract.

Scientific Evidence on the Health Benefits of Nattokinase

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(What's This?)

High Blood Pressure

There is preliminary evidence that nattokinase may reduce blood pressure modestly.

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Deep Vein Thrombosis (DVT) One study showed that this supplement reduced the risk of DVT often associated with long oversea flights.

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Thrombosis (Blot Clots) Animal studies that show nattokinase could offer benefits in dissolving clots.

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Alzheimer's Disease / Dementia


High Cholesterol - Probably not effective

Suggested Benefits and Traditional Uses

  • Angina
  • Anti-aging benefits
  • Anti-bacterial effects
  • Cancer
  • Chronic Fatigue Syndrome (CFS)
  • Endometriosis
  • Fibroids
  • Fibromyalgia
  • Hair loss (alopecia)
  • Heart disease
  • Hemorrhoids
  • Infertility
  • Muscle spasm and pain
  • Pain
  • Stroke
  • Uterine fibroids
  • Varicose veins

Research Studies to Support the Health Benefits of Nattokinase

High Blood Pressure

One well-designed clinical study involving 86 participants over 8 weeks showed that taking 2,000 FU daily caused a modest drop in blood pressure.

On average, the systolic blood pressure dropped by about 6 points (mm Hg).

Deep Vein Thrombosis (DVT)

In one well-designed clinical study, 204 subjects was split between using a product called Flite Tabs and a placebo.

The group taking Flite Tab (containing nattokinase and pycnogenol) did not suffer from DVT whereas 5 people in the placebo group experienced DVT.

Thrombosis (Blood Clots)

In one study, dogs with experimentally induced blood clots had their clots dissolved when given nattokinase by mouth. One clinical trial showed that nattokinase caused positive changes the clotting chemistry in the blood of healthy volunteers.

Other than the study done in the dogs, there are no human trials done to show that taking nattokinase could actually dissolve blood clots that result from a heart attack or certain types of stroke.

The positive results from animal studies definitely justify further research.

Fibroids and Alzheimer's Disease

Amyloids are proteins that are deposited in brain tissues in people with Alzheimer's disease (AD). It is not known whether amyloids actually cause AD or that they are just the "left-over" products from this progressive disease.

Some experts believe that getting rid of these amyloids may be helpful in preventing the disease from worsening.

One lab studies show that nattokinase has the ability dissolve these amyloid deposits. Whether this would work by taking the oral form of nattokinase is unknown.

In addition, because nattokinase is a proteolytic enzyme, some experts have suggested that it may be helpful in treating uterine fibroids.

High Cholesterol

One clinical study showed that taking nattokinase has no effect on the cholesterol levels of the volunteers with high cholesterol.

What's the Difference Between Nattokinase and Serrapeptase?

Serrapeptase is also a protein-digesting (proteolytic) enzyme. It is extracted from silkworms. Serrapeptase shows anti-inflammatory and blood thinning effects in both laboratory and animal studies.

See the article Health Benefits of Serrapeptase for further insights into the popular supplement and find out how well it works.

Isn't Nattokinase Destroyed by Stomach Acid?

Common sense tells us that nattokinase, which is a protein after all, would be quickly destroyed in the stomach by the acid and digestive juices.

This is the same reason what you can't take insulin (also a protein) by mouth and why it must be injected.

However, animals and humans given this enzyme by mouth do show beneficial changes in the blood chemistry.

This indicates that at least some nattokinase is getting into the bloodstream and that it is not totally inactivated by the digestive juices.

Moreover, most formulations of nattokinase have a specialized enteric-coating to allow the capsule to pass through the stomach intact. Once it gets into the intestine, the capsule coating dissolves and the enzyme is released for the body to absorb.

What Are the Side Effects of Nattokinase?

There is no report of side effects from using this enzyme. As well, the amount of nattokinase found in the Japanese food natto is not known to have any side effects.

When taken in amounts typically found in a Japanese diet, there is no harm.

What Are Some Possible Interactions and Dangers of Nattokinase?

Lab and animal studies clearly show that nattokinase taken as a pill form can thin the blood.

In theory, this may cause increased bleeding. This risk is further increased if the person is also taking the following medications or herbs:

  • Aspirin (ASA)

  • Plavix (clopidogrel)

  • Anti-inflammatory drugs (Voltaren, Advil, Motrin, Naprosyn, and others)

  • Coumadin (warfarin)

  • Other anticoagulant medications

  • garlic

Indeed there is one case report of bleeding in the brain (cerebral hemorrhage) caused by using nattokinase along with Aspirin.

Avoid these combination unless you are supervised by your health care professional. Always discuss using nattokinase with your doctor if you have a history of heart disease, stroke or are taking any type of medications that thins the blood.

There is no information known about the safety of using nattokinase during pregnancy or breast feeding.

Dose to Use

Typical dose used is 2,000 FU (Fibrinolytic Units) daily.

4,000 FU daily has been used in some clinical studies as well. The health benefits of nattokinase have been reported to be present at a dose of 2,000 FU daily.

Bottom Line

There's really not enough good research evidence to make a strong or convincing recommendation for using nattokinase for treating conditions like high blood pressure or for "dissolving" fibroid tissues.

Lab and animal studies are showing promise and some small clinical trials seem to show that it may be of benefit.

If you are thinking of using nattokinase for the purpose of preventing deep vein thrombosis (DVT), assuming that you are at risk, consult a qualified health care professional. DVT can be a serious life-threatening health condition, one you should not treat by yourself.

This also applies to using nattokinase for preventing blood clots. The body's blood clotting system is highly complex.

Always consult your health care provider when taking concentrated nattokinase capsules.