This guide explains how to assess nattokinase supplements using the information on the label and product page.
It focuses on product categories, ingredient declarations, serving information, suitability and the limits of permitted claims. It does not rank or score competing brands.
Commercial disclosure: The Health Improvers sells food supplements in this category. Where one of our products is used as a worked example, it is clearly identified and assessed using the same label-reading principles.
Nattokinase labels: six checks that matter
| Label check | Why it matters |
|---|---|
| FU per daily serving | FU describes measured enzyme activity under laboratory test conditions. Milligrams describe weight. |
| Milligrams and material name | The weight still helps identify how much nattokinase preparation is used, but it cannot replace the activity figure. |
| Capsules per daily serving | A front-label activity figure may require more than one capsule. |
| Pack duration and daily cost | Divide the capsule count by the stated daily intake, then divide the price by the number of days. |
| Allergen and dietary information | Nattokinase is commonly produced using fermented soy. Check the actual product’s soy declaration and capsule material. |
| Cautions | Medication, bleeding, pregnancy and planned-procedure warnings are particularly important for this category. |
What does FU mean?
FU stands for fibrinolytic units. It is an activity value produced by a laboratory assay: the test measures how the enzyme preparation acts on a specified substrate under defined conditions. It is not the number of enzyme molecules, a weight or a direct measure of what will happen in the body.
That distinction explains why two products can each contain 100mg of nattokinase preparation but declare different activity. For label comparison, use both figures:
- milligrams identify the weight of the preparation;
- FU identify the activity declared for that preparation.
Where possible, also check the manufacturer’s specification and whether the declared activity is guaranteed throughout shelf life. Numbers obtained using different assay methods may not be perfectly interchangeable.
Is 2,000 FU a proven or recommended dose?
No official UK recommended intake has been established for nattokinase. A 2,000 FU daily amount has appeared in human research, which explains why it is common on labels, but that does not make it a universally proven dose.
One double-blind trial gave 2,000 FU daily to 265 adults without clinical cardiovascular disease for a median of three years. It found no significant difference from placebo in progression of subclinical atherosclerosis, blood pressure or the laboratory measures reported. Smaller studies have examined other outcomes and sometimes used different quantities or preparations. The evidence should therefore be described as limited and mixed—not converted into a product promise.
How to compare the main formula types
| Formula type | What it offers | What to verify |
|---|---|---|
| Nattokinase-only | A simpler label and easier comparison | FU per daily serving, soy declaration, capsule count and cautions |
| Multi-ingredient complex | Nattokinase alongside nutrients or botanicals | Every ingredient amount, overlapping supplements and which ingredient supports any authorised claim |
| Milligram-only product | A weight figure without declared activity | Ask the seller for the FU specification; milligrams alone do not reveal enzyme activity |
| Higher-activity product | A larger declared FU figure | Serving size, assay basis, cautions and price per actual daily serving |
What can a nattokinase supplement legally claim in Great Britain?
Nattokinase has no authorised health claim in the current Great Britain Nutrition and Health Claims Register. A food supplement must not claim or imply that it prevents, treats or cures cardiovascular disease, blood clots, high blood pressure or any other medical condition.
A multi-ingredient formula may carry authorised wording for qualifying vitamins or minerals. That does not transfer the claim to nattokinase. In our formula, for example, authorised statements about normal immune function come from vitamin D and selenium; the normal thyroid-function and oxidative-stress statements come from selenium.
A transparent worked example: The Health Improvers Nattokinase Complex
At the time of review, our Nattokinase Complex costs £27.49. Its label and current product information declare:
- 100mg nattokinase preparation standardised to 2,000 FU per capsule;
- one capsule daily;
- 60 capsules, giving 60 days at the stated intake;
- approximately 46p per day at the current price;
- soy allergen declaration;
- a vegan capsule and UK manufacture;
- selenium, vitamin D and individually declared botanical ingredients.
This is a multi-ingredient complex, not a nattokinase-only product. The 2,000 FU figure describes declared enzyme activity; it is not an authorised health claim or a guarantee of cardiovascular benefit.
Safety belongs in the decision
Do not judge nattokinase only by activity and price. Check the complete caution panel before buying. People taking anticoagulant, antiplatelet or blood-pressure medicines, people with a bleeding or clotting condition, and anyone preparing for surgery or an invasive dental procedure should discuss the product with a doctor, pharmacist or procedure team before use. Do not stop or replace prescribed medication.
Read the full nattokinase safety guide before deciding whether the category is appropriate for you.
Frequently asked questions
Is 100mg nattokinase always 2,000 FU?
No. Milligrams and FU measure different things. The activity depends on the preparation and must be declared or supported by its specification.
Does a higher FU figure mean a better product?
Not automatically. It indicates greater declared activity under the relevant assay, but does not by itself establish effectiveness, safety, suitability or value.
Is 2,000 FU the recommended daily dose?
No official UK recommended intake exists. It is a commonly declared amount and has been used in studies, including a long-term trial that found no significant benefit on its primary vascular measures.
Is nattokinase the same as natto?
No. Natto is a fermented soybean food. Nattokinase is an enzyme produced during fermentation and supplied as a concentrated preparation in supplements.
Can nattokinase replace an anticoagulant?
No. Never replace or stop prescribed anticoagulant or antiplatelet treatment with a supplement. Speak to the clinician managing your medication.
How this guide was prepared
Product quantities, price, directions and allergen information were checked against the current Health Improvers product information on 3 August 2026. Claim wording was checked against GOV.UK guidance and the current GB claims register. Scientific context was checked against published human research indexed by PubMed and NHS anticoagulant guidance.
Sources
- Department of Health and Social Care: GB Nutrition and Health Claims Register
- GOV.UK: nutrition, health claims and supplement labelling
- PubMed: nattokinase atherothrombotic prevention randomized trial
- NHS: anticoagulant medicines—considerations
Continue with What Is Nattokinase? and Nattokinase Safety.
Always read the label and follow the directions. Food supplements are not a substitute for a varied and balanced diet and a healthy lifestyle. This article is general information, not medical advice.
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