Nattokinase Explained: The Enzyme from Japanese Natto

By the Zespo team · Updated 26 October 2026

Natto is a traditional Japanese food made by fermenting cooked soybeans with the bacterium Bacillus subtilis var. natto. It is famous for its strong smell and sticky, stringy texture.

What is nattokinase?

Nattokinase is an enzyme, a type of protein, produced by the bacteria during fermentation. It was identified in natto by the Japanese researcher Hiroyuki Sumi in 1980. Supplement nattokinase is extracted from fermented soy and purified.

What does FU mean?

Enzymes are measured by activity, not just weight. Nattokinase activity is given in FU (fibrinolytic units). A label might say "4,000 FU per serving", which is a more useful figure than milligrams alone.

Speak to a doctor before use if you take any regular medication or are due for surgery.

What to check before you buy

• The amount of each ingredient per serving, not just per capsule
• How many capsules make one serving and how many servings are in the pack
• Whether any ingredient sits inside an undisclosed "proprietary blend"
• An FSSAI licence number and the veg/non-veg mark on the pack

Label facts: Zespo Nattokinase 4,000 FU - 90 Veg Capsules

• Standardised enzyme activity: 4,000 FU in every single-capsule serving
• Single active ingredient, clearly labelled - no proprietary blend
• One capsule a day, a full 90-day supply in every bottle
• Made in India in a GMP-certified facility, FSSAI-licensed

See Zespo Nattokinase 4,000 FU - 90 Veg Capsules on zespo.in · Also on Amazon.in (search "Zespo").

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Zespo products are food supplements, not medicines. This article is for general information and is not medical advice. Take supplements as directed on the label and speak to a qualified healthcare professional if you are pregnant, nursing, taking medication or have a medical condition.