Does Nattokinase Contain Tyramine? Separating the Enzyme from the Food

November 14, 2025 •

3 min read

According to research, the fermentation process of natto, the traditional Japanese dish from which the enzyme is extracted, can produce significant levels of tyramine and other biogenic amines. This is a critical distinction because while the food contains tyramine, purified nattokinase supplements do not.

Quick Summary

Purified nattokinase supplements do not contain tyramine, unlike the fermented whole food, natto. This is a crucial distinction for individuals on a low-tyramine diet, such as those taking MAOI medications.

Key Points

Purified Supplements are Tyramine-Free: Unlike the whole fermented food natto, quality nattokinase supplements undergo purification, removing tyramine and other biogenic amines.
Natto Contains Tyramine: As a fermented soybean product, natto naturally contains varying levels of tyramine due to the bacterial action of Bacillus subtilis.
MAOI Patients Must Be Cautious: Individuals taking MAOI medications must strictly avoid high-tyramine foods like natto to prevent a dangerous rise in blood pressure.
Check for Certification: Reputable nattokinase supplements, such as those with the NSK-SD® mark, indicate a controlled process that ensures the removal of tyramine.
Always Consult a Doctor: If you are on any medication, particularly MAOIs, it is crucial to speak with a healthcare professional before taking any new supplement.
Fermentation is the Key Difference: The presence of tyramine is a byproduct of fermentation in natto, a process deliberately excluded or managed in the production of purified nattokinase extracts.

What Is Nattokinase and How Is It Different from Natto?

Nattokinase is an enzyme derived from natto, a traditional Japanese food made by fermenting soybeans with the bacterium Bacillus subtilis. The key to understanding the tyramine question lies in the difference between the whole food, natto, and a purified nattokinase supplement.

Natto (The Food): As a fermented food, natto is rich in microorganisms that break down the amino acid tyrosine into tyramine. The tyramine content in natto can be highly variable depending on the specific bacterial strains used, fermentation time, and processing methods. Some studies have shown levels of biogenic amines, including tyramine, that could be a concern for sensitive individuals.
Nattokinase (The Supplement): A purified nattokinase supplement is not the fermented food itself. Reputable manufacturers use specific extraction and filtration processes to isolate the nattokinase enzyme and remove other compounds, including the biogenic amines produced during fermentation. This means that the final supplement product, especially those from certified brands, is free of tyramine.

The Importance of Tyramine for MAOI Users

The primary concern with tyramine consumption relates to its interaction with monoamine oxidase inhibitor (MAOI) medications. MAOIs are a class of antidepressants that block the monoamine oxidase enzyme, which is responsible for breaking down excess tyramine in the body. If a person on an MAOI consumes a significant amount of tyramine, it can lead to a dangerous buildup of the substance, causing a sharp rise in blood pressure known as a hypertensive crisis. Symptoms of this include severe headache, stiff neck, and chest pain. For these individuals, a strict low-tyramine diet is medically necessary. Since natto is a fermented food, it is generally on the list of foods to avoid, creating the basis for the confusion about nattokinase supplements.

Comparison of Natto and Purified Nattokinase Supplements

To clarify the distinction, here is a breakdown of the key differences regarding tyramine.


Feature	Natto (Whole Fermented Food)	Purified Nattokinase Supplement
Source	Whole fermented soybeans	Enzyme extract from fermented soybeans
Tyramine Content	Contains varying amounts, can be significant	Tyramine-free (removed during purification)
MAOI Compatibility	Not recommended for those on MAOIs due to tyramine risk	Generally considered compatible, but medical supervision is advised
Processing	Fermented, unprocessed	Extracted, filtered, and purified
Other Compounds	Contains vitamin K2, biogenic amines, and soy isoflavones	Biogenic amines and vitamin K2 are typically removed
Form	Sticky, stringy food product	Capsules, tablets, or powder

Choosing a Nattokinase Supplement Wisely

For anyone concerned about tyramine, choosing a high-quality, purified nattokinase supplement is critical. Not all supplements are created equal, and product quality can vary. Look for supplements that meet these criteria:

Standardized Brands: Certain brands, like NSK-SD®, are standardized and tested to ensure they are free of both vitamin K2 and biogenic amines, including tyramine. This provides an added layer of assurance for sensitive individuals.
Independent Certification: Certification from third-party organizations like NSF International or ConsumerLab can help verify that a supplement contains the stated ingredients and has been properly manufactured.
Reputable Manufacturers: Choose products from well-known manufacturers who provide clear information about their purification processes and sourcing.

Potential Side Effects of Nattokinase (Not Related to Tyramine)

While purified nattokinase does not pose a tyramine risk, it does have other biological effects that warrant caution. The most significant is its potent blood-thinning, or fibrinolytic, property. Therefore, it should never be taken without medical supervision, especially if you:

Are already taking blood-thinning medications such as warfarin, heparin, or aspirin.
Have a history of bleeding disorders or a recent stroke.
Are scheduled for surgery (including dental surgery), as it should be discontinued at least one week prior.

Conclusion: Understand the Product, Stay Safe

The simple answer to the question "Does nattokinase contain tyramine?" is no, assuming you are referring to a quality, purified supplement. The fear stems from its origin in natto, a fermented food that does contain tyramine and is unsuitable for those on MAOIs. For the average consumer, this distinction is a matter of clarity, but for individuals on MAOI medication, it is a matter of safety. Always choose a reputable supplement and, most importantly, consult with a healthcare professional before adding nattokinase or any other new supplement to your regimen, especially if you are taking other medications.

For more information on tyramine and dietary considerations for MAOI users, the National Institutes of Health (NIH) website is an authoritative resource.

Frequently Asked Questions

Yes, the whole fermented food natto can contain varying levels of tyramine, a byproduct of the fermentation process using Bacillus subtilis.

Purified nattokinase supplements do not contain tyramine and are generally considered safe for MAOI users, but consultation with a doctor is essential, especially due to its blood-thinning effects.

The confusion arises because nattokinase is an enzyme extracted from the food natto, and the fermented food itself contains tyramine, unlike the purified supplement.

High-quality nattokinase supplements use specific extraction and filtration processes to isolate the pure enzyme while actively removing biogenic amines like tyramine and other fermentation byproducts.

Consuming tyramine while on MAOI medication can lead to a hypertensive crisis, a dangerous condition characterized by a severe and sudden spike in blood pressure.

Besides tyramine, natto can also contain other biogenic amines like histamine and β-phenylethylamine, though levels vary significantly.

Allergic reactions are rare but possible, particularly for individuals with a known allergy to soybeans. It's best to consult a healthcare provider if you have a soy allergy.