Serrapeptase and nattokinase can be taken together, and many supplement manufacturers already sell them as a combined product. No clinical evidence suggests the pairing is dangerous for otherwise healthy people who are not on blood-thinning medication. The two enzymes work through different mechanisms, which is part of the appeal: nattokinase targets fibrin in the bloodstream, while serrapeptase focuses on inflammatory proteins and tissue debris. What the research actually shows about this combination, though, is thinner than the marketing implies.
How the Two Enzymes Differ
Nattokinase comes from natto, a traditional Japanese food made by fermenting soybeans with the bacterium Bacillus subtilis. Its primary claim to fame is fibrinolytic activity, meaning it helps break down fibrin, the protein mesh that forms blood clots. Reviews of the evidence describe nattokinase as having fibrinolytic, antihypertensive, anti-atherosclerotic, lipid-lowering, and antiplatelet effects.1PubMed Central. Nattokinase: A Promising Alternative in Prevention and Treatment of Cardiovascular Diseases In simple terms, it works on the cardiovascular side of things: blood flow, clot formation, and artery health.
Serrapeptase (also called serratiopeptidase) is a proteolytic enzyme originally isolated from bacteria living in the gut of silkworms. Its main role is breaking down non-living tissue, including inflammatory byproducts, mucus, and fibrin to a lesser degree. It has a high affinity for cyclooxygenase enzymes (COX-I and COX-II), which are central players in the production of inflammatory molecules like prostaglandins and interleukins.2PubMed Central. The role of serratiopeptidase in the resolution of inflammation Its documented effects span anti-inflammatory, analgesic, anti-edemic (swelling-reducing), and anti-biofilm activity.3PubMed Central. Serratiopeptidase: Insights into the therapeutic applications
The enzymes overlap in one area: both have some fibrinolytic capacity. But nattokinase is far more potent at dissolving fibrin clots, while serrapeptase is far better at reducing localized inflammation and breaking down non-living protein debris in tissues. People who take both are generally trying to get the cardiovascular benefits of nattokinase alongside the anti-inflammatory benefits of serrapeptase.
What the Combination Studies Actually Show
Direct clinical evidence for the specific pairing is limited. The most frequently cited piece of evidence comes from a small pilot study of 13 people with pulmonary fibrosis, a serious lung condition involving scarring. Participants took two commercial supplements, Serracor-NK and Serra Rx, which contain both serrapeptase and nattokinase along with other enzymes. After 12 weeks, roughly 62% of subjects showed improvement on a well-being index, and about 85% reported better breathing scores.4PubMed Central. Effects of Systemic Enzyme Supplements on Symptoms and Quality of Life in Patients with Pulmonary Fibrosis—A Pilot Study The results are encouraging, but a pilot study with 13 people and no placebo group is really just a starting point. It tells you the combination was tolerated and that something improved, but it cannot tell you how much of the benefit came from nattokinase, how much from serrapeptase, and how much from the other ingredients.
On the laboratory side, an in vitro study tested the anticoagulating effects of serrapeptase, nattokinase, and bromelain individually and in pairs on bovine plasma. Samples treated with 2 mg of serrapeptase combined with 2 mg of nattokinase showed the highest clotting time of all the two-enzyme combinations, with an average activated partial thromboplastin time (aPTT) of 211 seconds, about 24% longer than untreated samples.5Longdom Publishing. Evaluating Effectiveness of Select Natural Remedies for their Anticoagulating Properties on Bovine Plasma: An In Vitro Study For comparison, combining bromelain with nattokinase extended clotting time by about 17%, and bromelain with serrapeptase by about 13%. The serrapeptase-nattokinase pair outperformed the other combinations, suggesting the two enzymes have additive anticoagulant effects, at least in a test tube. Whether that translates neatly to what happens inside the human body is another question, but it does provide a mechanistic rationale for the pairing.
Nattokinase on Its Own
Nattokinase has the deeper evidence base of the two enzymes. A systematic review and meta-analysis of randomized controlled trials found that nattokinase supplementation was associated with a meaningful drop in blood pressure: roughly 3.5 mmHg for systolic and about 2.3 mmHg for diastolic compared to placebo.6PubMed Central. Nattokinase Supplementation and Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis of Randomized Controlled Trials Those numbers are modest by pharmaceutical standards, but for a food-derived supplement taken daily, they are noteworthy.
A large clinical study of over 1,000 participants found that after 12 months of nattokinase consumption, carotid artery plaque size decreased by up to 36%, and the thickness of the carotid artery lining dropped significantly.7PubMed Central. Effective management of atherosclerosis progress and hyperlipidemia with nattokinase: A clinical study with 1,062 participants Those are striking numbers, though this study was not a placebo-controlled trial, which limits how much you can attribute to the enzyme versus other factors. A separate three-year intervention in healthy individuals using a placebo control found no significant difference in the rate of carotid artery thickening between nattokinase and placebo groups.6PubMed Central. Nattokinase Supplementation and Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis of Randomized Controlled Trials The discrepancy is worth noting. Nattokinase may be more effective in people who already have elevated cardiovascular risk factors than in healthy adults hoping to prevent problems that have not yet started.
Serrapeptase on Its Own
Most of the clinical data on serrapeptase comes from dental and surgical recovery studies, where its anti-swelling properties have been tested head to head against conventional anti-inflammatory drugs. In a randomized trial after impacted wisdom tooth surgery, patients who took serrapeptase had significantly less jaw stiffness and facial swelling by the fourth postoperative day compared to controls, though pain scores between the two groups were not significantly different.8PubMed Central. Efficacy of serratiopeptidase after impacted third molar surgery: a randomized controlled clinical trial Another trial compared serrapeptase to methylprednisolone, a corticosteroid, after the same type of surgery. By day five, the serrapeptase group actually showed better edema reduction than the steroid group.9PubMed Central. Comparison of clinical efficacy of methylprednisolone and serratiopeptidase for reduction of postoperative sequelae after lower third molar surgery
These findings are consistent with what practitioners who recommend serrapeptase describe: it is better for swelling and fluid buildup than for acute pain. If you are taking it expecting it to work like ibuprofen for a headache, you will be disappointed. If you are taking it because you have chronic sinus congestion, post-surgical swelling, or tissue inflammation that involves excess fluid, the evidence is more aligned with that use. The clinical data remains limited in scope, concentrated mostly in oral surgery recovery, and larger trials in other conditions are still needed.
The Blood-Thinner Warning
This is the most important practical concern with the combination. Both nattokinase and serrapeptase have anticoagulant properties. Nattokinase’s fibrinolytic activity is well documented. Serrapeptase contributes a milder version of the same effect. Combined, as the in vitro data above shows, their anticoagulant impact appears to be additive. That means the combination poses a real risk for anyone already taking blood-thinning medications like warfarin, heparin, or direct oral anticoagulants.
A sobering case report underscores this concern. A patient who had received a mechanical aortic valve replacement, which requires lifelong anticoagulation, self-substituted nattokinase for warfarin after reading about it on health websites. After nearly a year, the patient developed a blood clot on the prosthetic valve and needed a second open-heart surgery to replace it.10PubMed Central. Consequence of patient substitution of nattokinase for warfarin after aortic valve replacement with a mechanical prosthesis Nattokinase is not a replacement for prescription anticoagulants, and combining it with those medications can tip the balance toward excessive bleeding. Adding serrapeptase on top of that only increases the concern.
If you are on any blood-thinning medication, or if you are scheduled for surgery, you should talk to your doctor before taking either enzyme, let alone both. For people not on anticoagulants and without bleeding disorders, the combination does not appear to carry unusual risks based on the available evidence, but the honest caveat is that long-term safety data for the combination specifically is essentially nonexistent.
Timing, Dosing, and Getting Them to Your Gut
Both enzymes are proteins, which means stomach acid can destroy them before they reach the intestine where absorption occurs. This is why most reputable supplements use enteric coating or delayed-release capsules. Research on nattokinase compression coating has confirmed that coated tablets protect the enzyme from being broken down in simulated gastric juice and allow controlled release in the intestine.11PubMed. Stabilization and target delivery of Nattokinase using compression coating If you are shopping for either enzyme, look for enteric-coated or delayed-release formulations. A standard gelatin capsule without acid protection is likely to lose a significant portion of the enzyme’s activity before it ever reaches your bloodstream.
Both enzymes are typically taken on an empty stomach, at least 30 minutes before eating or two hours after a meal. The reasoning is straightforward: if there is food in your stomach, the enzymes will start breaking down food proteins instead of being absorbed intact. Nattokinase is commonly dosed at 2,000 fibrinolytic units (FU) per serving, while serrapeptase is usually measured in serrapeptase units (SPU), with common doses ranging from 60,000 to 120,000 SPU. Combined products typically contain both at these general ranges, though there is no universally agreed-upon dosing standard for either enzyme.
Some people take them at different times of day to avoid any hypothetical competition for absorption. There is no published evidence showing that taking them simultaneously reduces the effectiveness of either one, but splitting them (nattokinase in the morning, serrapeptase in the evening, for instance) is a common practice among long-term users, driven more by anecdote than by data.
Serrapeptase and Bacterial Biofilms
One of the more interesting lines of research on serrapeptase has nothing to do with inflammation in the traditional sense. Biofilms are protective structures that bacteria build around themselves, essentially a slimy matrix that shields colonies from antibiotics and the immune system. They are a major reason why certain infections, from chronic sinusitis to implant-associated infections, are so stubborn.
Laboratory research has shown that serrapeptase disrupts biofilms formed by Staphylococcus aureus, including methicillin-resistant strains (MRSA). The enzyme impaired biofilm formation, reduced bacterial viability, and altered the structural components of the bacterial cell wall.12PubMed Central. Serrapeptase impairs biofilm, wall, and phospho-homeostasis of resistant and susceptible Staphylococcus aureus Similar results have been shown against Pseudomonas aeruginosa, another bacterium notorious for forming resilient biofilms, particularly in the lungs of people with cystic fibrosis and in chronic wound infections. Serrapeptase inhibited biofilm formation on both plastic and glass surfaces and caused a dose-dependent decrease in bacterial viability.13PubMed Central. In vitro and in silico evaluation of the serrapeptase effect on biofilm and amyloids of Pseudomonas aeruginosa
This research is still at the lab bench. Nobody has run a clinical trial giving serrapeptase to patients with biofilm-associated infections to see if it helps. But the findings are consistent enough across bacterial species that researchers are actively investigating whether serrapeptase could work alongside antibiotics, potentially breaking open biofilms so that the drugs can reach the bacteria inside. Nattokinase does not have this property, which is one reason the two enzymes appeal to different concerns and why some people want both in their supplement routine.
Nattokinase and Gut Health
Beyond cardiovascular effects, nattokinase has shown some surprising activity in the gut. An animal study on chronic colitis found that nattokinase helped maintain the integrity of the intestinal lining and reversed changes to gut bacteria caused by the experimental colitis model. Specifically, it shifted the ratio of major bacterial groups, decreasing Firmicutes and increasing Bacteroidetes, a pattern generally associated with a healthier gut microbiome. It also suppressed an inflammatory metabolic pathway involving tryptophan breakdown.14Journal of Functional Foods. Nattokinase mitigated dextran sulfate sodium-induced chronic colitis by regulating microbiota and suppressing tryptophan metabolism via inhibiting IDO-1
This is a single animal study, so drawing broad conclusions about nattokinase as a gut health supplement would be premature. But it suggests that the enzyme’s effects extend beyond fibrin and blood clots. If confirmed in human studies, it could add another rationale for people interested in systemic enzyme therapy beyond cardiovascular support.
Immune Reactions and Long-Term Use
Both serrapeptase and nattokinase are foreign proteins, which means your immune system can, over time, recognize them as invaders and mount a response. This is a general concern with all therapeutic enzymes taken orally or injected. Allergic reactions are possible, and some researchers have raised the question of whether long-term use could trigger immune sensitization, where the body becomes increasingly reactive to the enzyme with repeated exposure.15IGI Global. Therapeutic Enzymes Used for the Treatment of Non-Deficiency Diseases
In practice, serious allergic reactions to oral serrapeptase and nattokinase appear to be uncommon, but they have been reported anecdotally. If you develop hives, breathing difficulty, or unusual swelling after starting either supplement, stop taking it. Some practitioners recommend cycling enzyme supplements, taking them for a period and then taking a break, partly to reduce the theoretical risk of immune sensitization. Whether cycling actually helps remains unproven, but it is a reasonable precaution given the lack of long-term safety studies for daily use spanning years.
The broader point is that “natural” does not equal “consequence-free.” Both enzymes are biologically active, and taking two active proteolytic enzymes together means more total enzyme activity in your system. For most healthy adults, this seems to be well tolerated, but the honest answer is that no large-scale, long-term safety trial has been published on the daily combined use of both enzymes over periods longer than a few months.
Who Is Already Selling the Combination
The supplement industry has not waited for clinical trials to catch up. Several products combine serrapeptase and nattokinase, often alongside other proteolytic enzymes like bromelain and papain. Brands like Serracor-NK, which was used in the pulmonary fibrosis pilot study mentioned earlier, market these blends for cardiovascular support, respiratory health, inflammation, and even scar tissue reduction. The fact that a commercial product was used in a published study is more common in the supplement world than in pharmaceuticals, but it does not mean the product itself has been validated. The study tested the blend, not any single brand’s proprietary formula.
When shopping for combination products, the same rules apply as for any enzyme supplement. Check for enteric coating. Look for activity units (FU for nattokinase, SPU for serrapeptase) rather than just milligrams, since enzyme weight and enzyme activity are not the same thing. A 100-mg capsule of nattokinase with low fibrinolytic activity is less useful than a 50-mg capsule with high activity. Third-party testing certifications add another layer of confidence that what is on the label matches what is in the capsule.