Product Reviews
Nattokinase Supplements Review

Reviewed and edited by Tod Cooperman, M.D. Tod Cooperman, M.D.
Initial Posting: 4/9/16
Nattokinase Supplements Tested by
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Summary: What You Need to Know About Nattokinase Supplements
  • Nattokinase supplements have been promoted to reduce the risk of blood clots and reduce blood pressure. However, the evidence for these effects in people remains preliminary: No study has definitively shown a reduction in clots in people from using nattokinase, although a reduction in blood clotting factors has been demonstrated, and nattokinase causes only a small reduction blood pressure. (See "What It Does")
  • When choosing a nattokinase supplement, it is important to look for one which lists its enzyme activity, which will be in FU (fibrin degradation or fibrinolytic units). Listing just the amount of enzyme in milligrams doesn't tell you enough, since not all nattokinase is equally active. You'll want a product providing at least 1,000 FU per pill or unit (see "What It Is"). Also, check that or another reputable independent 3rd party has verified the enzyme activity, as not all products provide the activity they list (see "What CL Found").
  • Products which found to contain their listed nattokinase enzyme activity are indicated as Approved in the 3rd column of the Results Table below. Among those, several provide the best value (i.e., greatest enzyme activity at lowest cost) -- see Top Picks.
  • Short term use of nattokinase supplements is generally well-tolerated but people who are taking medications such as blood-thinners or blood-pressure lowering medication should use them only with caution (See "Concerns and Cautions"). Nattokinase may also increase bleeding in the event of trauma or during and after surgery. Many nattokinase supplements contain soy and should not be used by people with an allergy to soy. See the last column of the Results Table to find out which claim soy.

What It Is:
Nattokinase is an enzyme with an anti-clotting effect -- it helps break down fibrin, a component of blood clots. It is derived from natto, a traditional Japanese food created by fermenting soybeans with bacteria (Bacillus subtilis). Nattokinase was identified and extracted from natto in 1987 by Dr. Hiroyuki Sumi (Sumi, Experientia 1987).

Nattokinase is measured in enzyme activity units called fibrin degradation (or fibrinolytic) units, or FU, which is a measure of its ability to break down fibrin. Some supplement labels only provide amounts (such as milligrams), however, the enzyme activity level (FU) is needed in order to know the potency of the enzyme.

What It Does:
Nattokinase is often promoted for reducing the risk of blood clots, due to its ability to breakdown fibrin. Nattokinase may also lower blood pressure. Consequently, it is has been promoted for general cardiovascular health. However, these uses are based largely on several small, preliminary clinical studies, as described below. Larger, longer, and better controlled studies are needed.

Blood Clots/Thrombosis
Laboratory and animal research suggest nattokinase may help to break down blood clots that can block blood flow in arteries (which can cause heart attacks and stroke) (Sumi, Acta Haematol 1990; Fujita, Biol Farm Bull 1995). However, evidence of this effect in people is limited to preliminary studies, none of which show reduced risk of clots using only nattokinase. One small study found that 4,000 FU of nattokinase (from two enteric-coated capsules) taken daily for two months decreased levels of blood-clotting factors (fibrinogen, factor VII, and factor VIII) by about 7% to 19% in healthy people as well as those with cardiovascular risk factors or undergoing dialysis. Blood pressure remained stable except for a slight decline (-3.73 mm Hg) in systolic blood pressure (Hsia, Nutr Res 2009). Similarly, a study in twelve men found that taking two enteric-coated capsules three times per day (a total daily dose of 1, 950 mg nattokinase) significantly increased measures of fibrin breakdown after eight days. (Sumi, Acta Haematol 1990). The same study reported that that consuming 200 grams of natto itself (which contains nattokinase) increased fibrinolytic activity (fibrin breakdown) for 2 to 8 hours after ingestion. In addition, a fairly recent study in 12 healthy men found that a single dose of nattokinase taken as a softgel providing 2,000 FU (NSK-SD, Japan Bio Science Laboratory Co.) significantly increased measures of fibrin breakdown and anti-thrombotic factors in the blood 4 hours after ingestion compared to placebo (Kurosawa, Sci Rep 2015).

One study using a combination of nattokinase and Pycnogenol has shown a lower risk of clots in men and women at high risk for deep vein thrombosis (DVT) who were not taking anticoagulant or anti-thrombotic medication. None of those who took 300 mg of this combination (amounts of each not stated) two hours before a long flight ( 7 — 8 hours) and again six hours after the first dose experienced a thrombotic event (a clot), while seven of those who took a placebo had a thrombotic event (Cesarone, Angiology 2003). However, it should be noted that four of the women who developed thrombosis had been taking oral contraceptive drugs, which can increase the risk of blood clots. It's not possible to draw conclusions from this study about the effect of nattokinase itself on the risk of blood clots. One product in this review, Solgar Nattokinase Complex, contains both nattokinase (2,000 FU) and Pycnogenol (5 mg).

Blood Pressure
Preliminary evidence suggest that natto may help lower blood pressure, possibly due to inhibition of angiotensin converting enzyme (ACE) inhibition (Okamoto, Plant Foods Hum Nutr 1995). A study in men and women with untreated high systolic blood pressure (130 to 159 mmHg) found that one capsule containing 2,000 FU nattokinase taken daily for 8 weeks reduced systolic and diastolic blood pressure, by 5.55 mmHg and 2.84 mmHg, respectively, compared to placebo (Kim, Hypertens Res 2008). In another study, noted in the section above, taking 4,000 FU of nattokinase lead to a slight decline (-3.73 mm Hg) in systolic blood pressure but not diastolic blood pressure (Hsia, Nutr Res 2009).

Alzheimer's Disease
Nattokinase has been shown in the laboratory to help break down amyloid-beta fibrils (the accumulation of which, in the brain, is associated with Alzheimer's disease) (Hsu, J Agric Food Chem). However, there are no studies on the effects of nattokinase supplementation in people with Alzheimer's disease, or studies on its effects on cognitive function or memory.

See the Concerns and Cautions section for more about the risk of bleeding and lowered blood pressure with nattokinase.

Quality Concerns and What CL Tested for:
Neither the Food and Drug Administration (FDA) nor any other federal or state agency routinely tests supplements for quality prior to sale. In order to help consumers identify products of better quality, purchased and tested nattokinase supplements to determine whether they possessed their labeled amount of enzyme activity. As the FDA only requires supplements to list the amounts of enzyme ingredients, for products listing only amounts and not enzyme activity, activity levels were determined by Tablets were tested for their ability to properly break apart (disintegrate) in solution.

See How Products Were Evaluated for more information on testing.

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