Nattokinase and serrapeptase get grouped together constantly — both are sold as “systemic enzymes,” both show up in the same supplement aisles, and both get credited with dissolving things the body doesn’t need.
That overlap makes it easy to assume they’re interchangeable. They aren’t.
This guide breaks down where they actually come from, what each one is backed by research to do, and how to tell which one fits what you’re trying to address.
Medical Overview
Nattokinase and serrapeptase are both proteolytic enzymes, meaning they break down proteins. That shared classification is where most of the confusion starts, because their sources, primary mechanisms, and evidence base are quite different.
Nattokinase’s research base centers on cardiovascular and circulatory markers. Serrapeptase’s research base centers on inflammation, swelling, and mucus after surgery or in sinus conditions. Neither is a treatment for a diagnosed medical condition, and anyone taking a prescription blood thinner or anti-inflammatory medication should check with a doctor before adding either one.
Where Each Enzyme Comes From
Nattokinase is extracted from natto, a fermented soybean food traditional in Japan, produced through fermentation by the bacterium Bacillus subtilis. Its fibrinolytic properties were first identified by Japanese researcher Hiroyuki Sumi, who observed that natto could dissolve artificial fibrin clots in lab testing.
Serrapeptase, sometimes labeled serratiopeptidase, was originally isolated from bacteria in the gut of silkworms, where it’s thought to help the silkworm break down its cocoon. Commercial serrapeptase today is produced through bacterial fermentation rather than sourced from silkworms directly.
How They Work
Both enzymes are classified as proteolytic, but what they target and how they’re used clinically diverge.
Nattokinase acts primarily on the fibrinolytic pathway — the process that breaks down fibrin, the protein mesh that forms blood clots. Research on nattokinase describes it as a serine protease with the ability to directly degrade fibrin and to support the activity of plasmin, the body’s own clot-dissolving enzyme, which is the basis for its use in circulatory support.
Serrapeptase’s clinical research centers on a different target: inflammatory proteins and mucus rather than blood clotting directly. Reviews of serrapeptase’s therapeutic use describe pre-clinical and clinical findings on its anti-inflammatory activity, along with evidence for reducing mucus viscosity in people with chronic sinusitis — a use case with no real equivalent in the nattokinase research.
What the Research Actually Supports
Nattokinase: Circulation and Cardiovascular Markers
Nattokinase’s strongest evidence is in circulatory and cardiovascular outcomes — blood pressure, blood viscosity, and clotting-related markers, generally studied at doses around 2,000 FU per day. This is covered in more depth in our nattokinase dosage guide.
Serrapeptase: Post-Surgical Swelling and Sinus Symptoms
Serrapeptase has a different, more scattered evidence base. Some of the more consistent findings come from oral surgery: a randomized controlled trial of patients undergoing third molar (wisdom tooth) extraction found that serrapeptase measurably improved swelling and jaw mobility (trismus) on day 4 compared to placebo.
A broader review of serrapeptase’s therapeutic applications also describes findings in chronic sinusitis, where serrapeptase was shown to reduce the viscosity of nasal mucus, supporting its use for congestion-related symptoms, though the same review notes the effect on mucus elasticity was less consistent.
Not every serrapeptase trial has shown a benefit, though. Some studies comparing serrapeptase to other anti-inflammatory options for postoperative pain and swelling have found no meaningful difference from placebo, which is part of why serrapeptase’s evidence base is generally described as more mixed than nattokinase’s.
Nattokinase vs Serrapeptase at a Glance
| Nattokinase | Serrapeptase | |
|---|---|---|
| Source | Fermented soybeans (natto), Bacillus subtilis | Originally silkworm gut bacteria; now bacterial fermentation |
| Primary mechanism | Fibrinolytic — breaks down fibrin, supports plasmin activity | Proteolytic — targets inflammatory proteins and mucus |
| Strongest evidence for | Circulation, blood pressure, clotting-related markers | Post-surgical swelling, sinus mucus, localized inflammation |
| Typical unit of measure | FU (fibrinolytic units) | SPU or mg (serratiopeptidase units) |
| Main safety concern | Bleeding risk with anticoagulants | Interacts with anti-inflammatory and blood-thinning medications |
| Not interchangeable for | Sinus/inflammation-specific use | Cardiovascular/circulation-specific use |
Can You Take Them Together?
Some products combine nattokinase and serrapeptase on the theory that “more enzyme activity” is better. Because both enzymes affect proteins involved in clotting and inflammation, combining them increases the same category of risk each one carries individually — namely bleeding risk — without a clear, matching body of research on the combination itself.
If you’re on any blood-thinning or anti-inflammatory medication, treat a combined product the same way you’d treat either enzyme alone: talk to a doctor first, not after.
Which One Fits Your Goal
If your goal is circulatory or cardiovascular support — healthy blood pressure, blood viscosity — nattokinase has the stronger and more direct research base.
If your goal is inflammation, swelling, or sinus congestion — post-surgical recovery, chronic sinus symptoms — serrapeptase’s research is more relevant, though still more limited and mixed than nattokinase’s cardiovascular data.
If you’re not sure which applies to you, that’s a reasonable question to bring to a doctor rather than defaulting to a combination product, since neither enzyme is a treatment for a diagnosed condition either way.
FAQs
Is serrapeptase stronger than nattokinase?
“Stronger” depends on what you’re measuring. Nattokinase has more consistent evidence for cardiovascular and circulatory markers, while serrapeptase’s evidence is more specific to post-surgical swelling and sinus mucus. Neither is broadly “stronger” across all uses.
Can serrapeptase replace nattokinase, or vice versa?
No. They’re both proteolytic enzymes but act on different biological targets, so one isn’t a substitute for the other’s specific, research-backed use case.
Which one is safer for someone on blood thinners?
Neither is automatically safer — both have documented interaction risk with anticoagulant and antiplatelet medications. Anyone on blood thinners should talk to their doctor before starting either enzyme.
Do nattokinase and serrapeptase have the same side effects?
There’s overlap, mainly around bleeding risk and gastrointestinal upset, but they aren’t identical. Serrapeptase is more commonly enteric-coated specifically because it can be broken down by stomach acid before reaching the intestine.
Is it safe to take nattokinase and serrapeptase together?
This should be discussed with a doctor first. Combining two proteolytic enzymes that both affect clotting-related pathways compounds the same risk category rather than simply adding two separate benefits.
Final Thoughts
Nattokinase and serrapeptase share a category label, but they come from different sources, act on different biological targets, and are backed by different — and differently sized — bodies of research.
Nattokinase is the better-supported choice for circulatory and cardiovascular goals. Serrapeptase’s evidence fits more specifically with post-surgical swelling and sinus-related symptoms.
Anyone on blood-thinning or anti-inflammatory medication should talk to a doctor before starting either enzyme, alone or combined.
If nattokinase fits what you’re looking for, see our full comparison of top-rated products: Best Nattokinase Supplements.