What "4,000 FU" Means
FU stands for Fibrinolytic Units, a standardised way of expressing how biologically active an enzyme sample is. When a Nattokinase Plus 200mg capsule is labelled as delivering 4,000 FU, it means the enzyme in that capsule has been measured, in a controlled laboratory assay, to perform a specific, quantifiable amount of fibrinolytic (clot-breakdown-type) activity.
In simple terms: FU is nattokinase's version of a potency rating, similar in spirit to how some vitamins are measured in International Units (IU) rather than just milligrams, because what matters most for an enzyme is what it actually does, not only how much of it there is by weight.
Why Enzymes Are Measured in Activity Units
Weight alone doesn't always tell the full story for an enzyme. Two samples of the same enzyme, extracted or processed slightly differently, could weigh the same but have different levels of actual biological activity. Standardising to an activity-based unit like FU allows manufacturers to give a consistent, comparable potency figure, so that a "4,000 FU" capsule reliably delivers the same activity batch after batch.
- Consistency — every capsule is standardised to the same measured activity level.
- Comparability — FU makes it possible to compare potency across different nattokinase products on a like basis.
- Research relevance — most published studies on nattokinase report dosage in FU, making it the more meaningful figure for comparing to clinical research.
Milligrams vs. Fibrinolytic Units
You'll typically see both figures on a nattokinase label — for example, "200 mg / 4,000 FU." The milligram figure tells you the weight of the nattokinase-containing extract in the capsule, while the FU figure tells you its measured activity. For a given manufacturing process, the two numbers move together in a predictable ratio, which is why Aiva Wellness lists both on the Nattokinase Plus 200mg supplement facts panel.
How to Read the Full Label
Beyond the FU rating, a few other details on a nattokinase label are worth checking:
- Serving size — the Nattokinase Plus 200mg product specifies one capsule per serving.
- Servings per container — 30 capsules, roughly a one-month supply at the labelled serving.
- Other ingredients — a short, transparent list of stabilising and shell-forming components.
- Allergen information — since nattokinase is soy-derived, allergen labelling is worth noting if you're soy-sensitive.
This article explains how to read a supplement label and is not medical advice or a personal dosage recommendation. Nattokinase may interact with blood-thinning medication. Please consult your doctor before starting any new supplement, particularly if you are pregnant, breastfeeding, on medication, or managing an existing health condition, and always follow the dosage stated on the product label.
What This Product Specifically Contains
According to the Aiva Wellness product specification, Nattokinase Plus 200mg is derived from fermented soybean (natto) and delivers 4,000 FU (200 mg) of high-potency enzyme per one-capsule serving, with 30 capsules per container. If you're weighing this against the lower-potency 100mg option, our side-by-side comparison of Nattokinase 100mg vs 200mg walks through the practical differences in more detail.
Frequently Asked Questions
A higher FU figure indicates greater measured fibrinolytic activity per serving, but "stronger" is not the same as "more suitable for you." The right potency depends on individual factors best discussed with a doctor.
Milligrams describe the weight of the nattokinase extract, while FU describes its measured biological activity. Showing both gives a fuller picture of what a serving actually delivers.
The Aiva Wellness Nattokinase Plus 200mg pack contains 30 capsules, with one capsule as the labelled serving size.
Yes, most published clinical studies on nattokinase report dosage in Fibrinolytic Units, which is part of why FU is considered the more meaningful potency figure for this enzyme.
The Takeaway
"4,000 FU" is simply a standardised measure of how active the nattokinase enzyme is in each Nattokinase Plus 200mg capsule. Understanding FU makes it easier to read supplement labels accurately and have a more informed conversation with your doctor about whether this product fits your routine.
Referenced Research & Sources
- Wikipedia — Nattokinase
- Aiva Wellness — Nattokinase Plus 200mg product specification sheet
- ScienceDirect Topics — Natto: an overview
