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What is Nattokinase?


Updated May 16, 2014

What is Nattokinese
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What is Nattokinase?:

Nattokinase is an enzyme extracted from natto, a Japanese food made from fermented soybeans. To make natto, boiled soybeans are combined with the bacteria Bacillus subtilis natto.

Natto is a popular breakfast food in Japan, where it is eaten with rice. Natto has a strong, cheese-like smell; a nutty, salty flavor; and a sticky consistency.

The supplement nattokinase is purified from natto and made into tablets and capsules, so it doesn't have the same strong smell or taste as the food. It's available in health food stores and online.

Why Do People Use Nattokinase?:

Nattokinase is thought to be help dissolve abnormal blood clots. Abnormal blood clots can cause heart attacks and strokes, as well as conditions such as phlebitis, pulmonary embolism, or deep vein thrombosis.

How is Nattokinase Believed to Work?:

One theory is that it dissolves the tiny fibers (fibrin) that form the strong mesh in blood clots. Streptokinase and urokinase, drugs administered intravenously after a heart attack or stroke, work the same way. Nattokinase, however, is absorbable by mouth and believed to be longer-acting.

Nattokinase is said to have similar clot-dissolving abilities as plasmin, a natural enzyme in blood.

In contrast, aspirin reduces stickiness of blood cells (platelets) that, together with fibrin strands, make up blood clots. The drug Coumadin (warfarin) works on abnormal clotting by preventing fibrin strands from forming a clot.

Is There Evidence That Nattokinase Works?:

There is very limited evidence that nattokinase can break up blood clots. Studies have mostly involved animals or test tube research.

There haven't been any large, well-designed studies showing that nattokinase is effective or safe in humans.

In one study, people were given nattokinase or a placebo before a long distance flight. Seven of the 92 people who took the placebo developed a clot, compared to none of those who took nattokinase. The design of the study, however, has been questioned.

What are the Potential Side Effects of Nattokinase?:

Nattokinase shouldn't be used by people with bleeding disorders, or by people who are taking Coumadin (warfarin), aspirin, or any other drug that influences blood clotting (unless under doctor's supervision).

Nattokinase may lower blood pressure.

The safety of nattokinase supplements in healthy people isn't known. Use of the supplements could theoretically lead to easy bruising and excessive bleeding.

Natto and many nattokinase supplements contain vitamin K. Large amounts of vitamin K may decrease the effectiveness of Coumadin.

The safety of nattokinase in pregnant or nursing women or children is unknown.


Cesarone MR, Belcaro G, Nicolaides AN, Ricci A, Geroulakos G, Ippolito E, Brandolini R, Vinciguerra G, Dugall M, Griffin M, Ruffini I, Acerbi G, Corsi M, Riordan NH, Stuard S, Bavera P, Di Renzo A, Kenyon J, Errichi BM. Prevention of venous thrombosis in long-haul flights with Flite Tabs: the LONFLIT-FLITE randomized, controlled trial. Angiology. 54.5 (2003) 531-539.

Sumi H, Hamada H, Nakanishi K, Hiratani H. Enhancement of the fibrinolytic activity in plasma by oral administration of nattokinase. Acta Haematol. 84.3 (1990): 139-143.

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