Medically Reviewed by Melinda Ratini, MS, DO on September 06, 2023
2 min read

Nattokinase is a natural enzyme. It comes from natto, a Japanese soybean dish.

There's some early evidence that nattokinase may have benefits for heart and artery health. One study shows that a nattokinase supplement lowers the risk of blood clots after long plane flights. It may help reduce narrowing of the arteries.

Other studies show that nattokinase may help lower blood pressure. However, we need more research to see if it is effective.

Optimal doses of nattokinase have not been set for any condition. Quality and active ingredients in supplements may vary widely from maker to maker. This makes it very hard to set a standard dose. Ask your doctor for advice.

Researchers first found nattokinase in the Japanese food natto, made with fermented soybeans. It seems that the fermentation process makes nattokinase. You can't get nattokinase from other soy foods.

Tell your doctor about any supplements you're taking, even if they're natural. That way, your doctor can check on any potential side effects or interactions with medications.

Side effects. In food, nattokinase is safe. More studies are needed to see if nattokinase taken as a supplement is safe for repeated or long-term use.

Risks. If you have any blood clotting disorders, don't take nattokinase supplements unless a doctor says it's safe. You may need to stop taking nattokinase if you're planning to have surgery.

Given the lack of evidence about its safety, doctors don't recommend nattokinase for children or for women who are pregnant or breastfeeding.

Interactions. If you take any medications regularly, talk to your doctor before you start using nattokinase supplements. The supplements could interact with blood thinners and other drugs that reduce clotting, like aspirin and ibuprofen. They could cause excess bleeding and bruising.

The U.S. Food and Drug Administration (FDA) does regulate dietary supplements; however, it regulates them under a different set of regulations than foods and drugs. It is up to the manufacturers to assure safety and accurate labeling.