Taking nattokinase alongside a statin is generally considered safe based on available research, and early evidence suggests the combination may even enhance cholesterol-lowering results. However, nattokinase has real blood-thinning effects that require caution, particularly if you’re also on anticoagulant or antiplatelet medications in addition to your statin.
How the Two Work Differently
Statins and nattokinase lower cardiovascular risk through completely different mechanisms, which is part of the reason they can be paired. Statins block an enzyme in your liver that produces cholesterol, which directly reduces LDL (the “bad” cholesterol). Nattokinase, an enzyme extracted from the fermented soybean food natto, works on a broader set of targets. It breaks down fibrin, the protein that forms the structural backbone of blood clots, through multiple pathways. It also converts inactive clot-dissolving compounds in your blood into their active forms and degrades a protein that normally slows down clot breakdown.
Beyond its clot-dissolving activity, nattokinase has its own modest lipid-lowering effects. In patients with high cholesterol, 26 weeks of nattokinase at 6,500 FU (fibrinolytic units) per day reduced total cholesterol, LDL cholesterol, and triglycerides while raising HDL (“good”) cholesterol. Statins are well known for lowering LDL but do relatively little to raise HDL, so the two fill in each other’s gaps.
What the Research Shows About Combining Them
Animal studies have directly tested the combination. Rats on a high-fat diet that received both atorvastatin and nattokinase showed more significant improvements in blood lipids, less liver damage, and lower levels of inflammatory markers than rats given the statin alone. That last point matters because muscle pain and liver stress are among the most common reasons people stop taking statins.
In a human study, 30 patients with thickened carotid artery walls (an early sign of atherosclerosis) were split into two groups. One group took 1,500 FU per day of nattokinase on top of their standard lipid-lowering medication, while the other took only the medication. After three months, both groups saw improvement, but the nattokinase group had significantly greater reductions in artery wall thickness and plaque size. Plaque shrank by about 36.6% in the nattokinase group compared to 11.5% in the statin-only group.
A large, multicenter randomized controlled trial is also underway in China, testing a natto and red yeast rice supplement combined with simvastatin against each treatment alone. The primary outcome is LDL cholesterol change at three months. Results from this trial should provide stronger evidence on whether the combination delivers meaningful added benefit in a well-controlled setting.
The Real Risk: Bleeding
The most important concern with nattokinase isn’t a direct interaction with statins. It’s nattokinase’s effect on blood clotting. In an eight-week trial of people with borderline-to-moderate high cholesterol, nattokinase significantly prolonged multiple clotting measurements: the time it took platelets to form a plug, prothrombin time (how long the blood took to clot), and activated partial thromboplastin time (another clotting speed measure). In practical terms, nattokinase makes your blood clot more slowly.
For most people taking only a statin, this is a manageable concern. But many statin users are also prescribed blood thinners like warfarin or antiplatelet drugs like aspirin or clopidogrel. Layering nattokinase on top of those creates a cumulative blood-thinning effect that can become dangerous. A case report published in Cureus described an elderly woman with atrial fibrillation who experienced severe internal bleeding and died after taking over-the-counter nattokinase. Her fibrinolytic activity spiked within two to eight hours of taking it. While her situation involved multiple risk factors, it illustrates that nattokinase’s anticoagulant effects are not trivial.
If your statin is your only cardiovascular medication and you have no bleeding disorders, the bleeding risk from adding nattokinase is lower. If you take any blood thinner or antiplatelet drug alongside your statin, the risk profile changes substantially.
Dosage Used in Studies
Nattokinase potency is measured in fibrinolytic units (FU), not milligrams. Most clinical trials have used doses between 2,000 and 6,500 FU per day. A standard supplement capsule contains 100 mg standardized to 2,000 FU, taken once daily in the morning. The study showing plaque and artery wall improvements alongside statins used 1,500 FU per day, while the study showing cholesterol improvements as a standalone used 6,500 FU per day over 26 weeks.
There is no established guideline from major cardiology organizations recommending nattokinase, either alone or in combination with statins. It remains classified as a dietary supplement, meaning it is not regulated the same way prescription drugs are and product quality can vary between manufacturers. Look for supplements labeled with a specific FU count per capsule rather than just a milligram weight.
Who Should Be Cautious
Certain situations call for extra care or avoidance:
- Taking blood thinners or antiplatelet drugs. The combined blood-thinning effect can raise bleeding risk significantly.
- Upcoming surgery. Because nattokinase’s clot-dissolving effects peak within two to eight hours and its influence on clotting times is measurable for weeks, stopping well before any planned procedure is important.
- History of bleeding disorders or hemorrhagic stroke. Nattokinase’s multiple anticoagulant pathways make it unsuitable for people already prone to bleeding.
- Pregnancy or breastfeeding. There is insufficient safety data in these populations.
For people taking a statin alone for high cholesterol and looking to add nattokinase for its clot-dissolving or additional lipid-lowering properties, the current evidence does not show a harmful direct interaction between the two. The combination may offer complementary benefits: statins handling the heavy lifting on LDL, nattokinase contributing to HDL improvement and plaque reduction while adding fibrinolytic activity that statins do not provide. The critical variable is what else is in your medication regimen, because nattokinase’s anticoagulant effects are real and clinically measurable.