If you've looked at heart or circulation supplements recently, you've likely seen Nattokinase listed as a headline ingredient — often with a Japanese-sounding name and a vague "supports healthy blood flow" claim next to it. It's not a synthetic compound or a trendy extract; it comes from one of Japan's most distinctive traditional foods. Here's what it actually is, what it's traditionally used for, and what to check before choosing a product.
Where Nattokinase actually comes from
Natto is a traditional Japanese food made by fermenting steamed soybeans with the bacteria Bacillus subtilis, producing its signature sticky texture and strong flavour. During this fermentation process, the bacteria produce an enzyme — Nattokinase — that can be isolated and concentrated for supplement use. It's not synthesised in a lab; it's a byproduct of a centuries-old fermentation tradition, extracted and standardised for consistent supplement dosing.
What it's traditionally associated with
Nattokinase is traditionally linked to fibrinolytic activity — the body's natural process of breaking down fibrin, a protein that forms part of a blood clot's structure. This is the basis for its inclusion in cardiovascular wellness formulas, where it's positioned as supporting healthy circulation and normal blood flow as part of an overall heart-conscious routine, rather than as a treatment for any diagnosed condition.
Understanding FU: the number that actually matters
Much like extract ratios in botanical supplements, Nattokinase labels often lead with a milligram weight — but the more meaningful number is FU, or Fibrinolytic Units, which measures the enzyme's actual activity level rather than its raw weight. Two products with identical milligram amounts can have very different FU counts depending on extraction and standardisation quality, so checking for a stated FU value is a more reliable indicator of what you're actually getting.
Why it's often paired with other cardiovascular ingredients
Cardiovascular wellness involves multiple overlapping processes — circulation, cholesterol metabolism, blood vessel health — which is why Nattokinase is rarely the sole ingredient in a well-formulated heart health product. This mirrors the same combination-formula logic covered in our piece on TCM hair growth ingredients and our prostate ingredient comparison — supporting one health goal from multiple complementary angles rather than relying on a single compound.
An important safety note
Because Nattokinase is associated with fibrinolytic activity, anyone currently taking prescription blood thinners or anticoagulant medication should speak with a doctor before adding it to their routine. This isn't a precaution unique to Nattokinase — it applies to most supplements that interact with the body's clotting processes — but it's worth stating clearly rather than glossing over.
GreenKare Clear Blood Vessel
Formulated with standardised Nattokinase to support healthy circulation and normal blood flow, as part of a broader cardiovascular wellness routine. Made in Singapore, GMP Certified.
Learn More →Setting realistic expectations
Nattokinase is intended as ongoing daily support, not an acute treatment — its traditional use assumes consistent intake over time as part of a broader cardiovascular-conscious lifestyle, alongside good diet, regular movement, and medical check-ins rather than as a substitute for any of them.
Frequently Asked Questions
What is Nattokinase?
An enzyme extracted from natto, a traditional Japanese fermented soybean food, produced by the bacteria Bacillus subtilis.
What is it traditionally used for?
Supporting healthy blood circulation and the body's natural fibrinolytic activity.
What does FU mean on a label?
Fibrinolytic Units — the standard measure of enzymatic activity, more informative than milligram weight alone.
Can I take it with blood-thinning medication?
Only under medical guidance, given its association with fibrinolytic activity.
This article is for general health information only and is not intended as medical advice or diagnosis. Dietary supplements are not a substitute for a balanced diet. Please consult a doctor before starting any new supplement, especially if you are on blood-thinning or anticoagulant medication.
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