Nattokinase & Arterial Plaque: The Honest Evidence

🧬 Origin & Classification

Nattokinase is a serine protease enzyme produced by the bacterium Bacillus subtilis (specifically B. subtilis var. natto) during the fermentation of soybeans into natto — a traditional Japanese soy food. The enzyme is formally classified as subtilisin NAT, a member of the subtilisin family of proteases.

Nattokinase is sold as an oral supplement, but how much reaches the bloodstream in active form is not established by the studies cited on this page.

🇯🇵 Traditional Use & Epidemiological Context

Natto has been a staple of the Japanese diet — particularly in eastern Japan — for centuries. One large Japanese prospective cohort study has examined natto intake and cardiovascular mortality directly: following 29,079 Japanese adults for ~16 years — the Takayama study (Nagata et al., American Journal of Clinical Nutrition, 2017; PMID 27927636) — found that the highest quartile of natto intake, versus the lowest, was significantly associated with reduced cardiovascular disease mortality (HR 0.75).

While correlation doesn't prove causation (the Japanese diet has many cardioprotective elements), and natto contains more than nattokinase, so this association alone cannot show that isolated nattokinase supplements have the same effect.

📋 Regulatory Status

Nattokinase is classified as a dietary supplement in the United States and is not FDA-approved as a drug for treating or preventing any disease. It is available over the counter. In Japan, it is classified as a functional food ingredient. The Japan Nattokinase Association (JNKA) certifies quality standards for nattokinase supplements.

📊 Study Overview: n=1,062

The most-cited nattokinase plaque study (Chen et al., Frontiers in Cardiovascular Medicine, 2022; PMID 36072877) enrolled 1,062 participants and measured changes in carotid artery intima-media thickness (CIMT) and atherosclerotic plaque size over 12 months. CIMT is a validated surrogate marker for systemic atherosclerosis — thicker arterial walls and larger plaques correlate with higher cardiovascular event risk.

At a dose of 10,800 FU/day — roughly five times a typical 2,000 FU supplement — the study reported significant reductions in carotid intima-media thickness and plaque size, with "improvement rates" spanning 66.5% to 95.4%. Critically, the same study found the lower dose of 3,600 FU/day ineffective, directly challenging the dose most supplements sell.

Read this before believing the headline. This is a single study with significant conflicts of interest: several authors were employed by Sungen Bioscience (a nattokinase manufacturer) and by Sinopharm. The paper was not placebo-controlled, it carries a published erratum (Front Cardiovasc Med, Dec 2022), and the "improvement rate" metric is not the same as a clean percentage of plaque dissolved. Treat it as promising but preliminary — not proof.

🚫 The "95% Plaque Reduction" Claim — Debunked

A viral clip circulating on X claims nattokinase produces "~95% plaque reduction" or "reverses arterial plaque." Here's what's actually going on:

• 🔸 The 95.4% figure is the top of a range ("improvement rates ranged from 66.5 to 95.4%"), not a uniform 95% shrinkage of everyone's plaque.
• 🔸 It comes from one industry-funded study (PMID 36072877) whose authors include employees of the supplement maker — and it has a published erratum.
• 🔸 It required 10,800 FU/day. Most "nattokinase" capsules deliver 2,000 FU, and the same study found 3,600 FU/day did nothing.
• 🔸 There is no large, independent, placebo-controlled replication confirming plaque reversal in humans.

Bottom line: nattokinase is a legitimate fibrinolytic enzyme with real cardiovascular signals (especially for blood pressure — see below), but "dissolves 95% of arterial plaque" is marketing-grade overreach, not an established clinical fact.

🔍 What the Pooled Evidence Says

A 2023 systematic review and meta-analysis of randomized controlled trials (Li et al., Reviews in Cardiovascular Medicine, 2023; PMID 39076715) pooled 6 RCTs with 546 participants (PROSPERO CRD42022315020). Its strongest, most reproducible finding was on blood pressure, not plaque — nattokinase significantly lowered systolic and diastolic pressure (detailed in the next section). Notably, lipids moved the wrong way: at relatively low total doses, nattokinase raised total cholesterol (MD +5.27) and LDL (MD +6.49) and lowered HDL (MD −2.76), and at higher total doses total cholesterol was also higher than with control interventions (MD +3.18). It also produced a slight rise in blood glucose (MD +0.40). The authors concluded nattokinase is a reasonable adjunct for hypertension, while calling for more work on whether its effects are dose-dependent.

📉 Clinical Blood Pressure Data

A randomized, double-blind, placebo-controlled trial (Kim et al., Hypertension Research, 2008; PMID 18971533) enrolled 86 participants with borderline or mild hypertension. After 8 weeks of nattokinase supplementation (2,000 FU/day), net changes in the treatment group compared with the control group were:

These reductions were statistically significant. While modest compared to prescription antihypertensives, this effect is notable for a dietary supplement.

Confirmed by pooled data The blood-pressure signal is the part of nattokinase's profile that holds up across studies. The 2023 meta-analysis of 6 RCTs (n=546; PMID 39076715) found a pooled reduction of −3.45 mmHg systolic (95% CI −4.37 to −2.18) and −2.32 mmHg diastolic (95% CI −2.72 to −1.92), both highly significant. The pooled estimate is smaller than the 2008 single-trial result (−5.55 mmHg systolic), but its confidence interval is narrow.

🔬 Mechanism: Not Yet Pinned Down

The only mechanistic finding in the cited blood-pressure trial (Kim et al., 2008) is a drop in plasma renin activity (−1.17 ng/mL/h versus control). That points toward the renin–angiotensin system, but direct ACE inhibition in humans has not been shown in the studies cited here. Either way, nattokinase should be viewed as a complementary approach, not a replacement for prescribed antihypertensives.

✈️ Deep Vein Thrombosis (DVT) Prevention

An often-cited randomized controlled trial in Angiology (the LONFLIT-FLITE study; Cesarone et al., 2003; PMID 14565628) gave high-risk long-haul flyers Flite Tabs or placebo: no DVT occurred among 94 treated subjects who completed the study, versus 5 DVTs among 92 controls. Honest caveat — Flite Tabs are a combination product ("pinokinase": nattokinase plus Pycnogenol), so the benefit can't be attributed to nattokinase alone. It's supportive context, not clean nattokinase-only evidence.

A 2021 real-world series of 153 patients admitted for vascular disease (Nutrients; PMID 34199189) gave nattokinase 100 mg/day, in some groups alongside fondaparinux or enoxaparin, and reported improved symptoms with no adverse drug reactions or drug interactions. It was uncontrolled, so it speaks to tolerability under medical supervision — not to DVT prevention or proven event reduction.

🧠 Stroke Prevention & Neuroprotection

Most strokes are ischemic — caused by blood clots blocking cerebral arteries. Nattokinase's proposed anti-platelet and fibrinolytic actions target clot formation, but whether that lowers stroke risk in people has not been tested in the studies cited here.

Direct stroke-prevention data are lacking. Its proposed anti-thrombotic action and its blood pressure-lowering effect suggest a possible cardio-cerebrovascular protective role, but no study cited here tested nattokinase supplements against stroke. The observational Takayama cohort (PMID 27927636) found the highest quartile of natto food intake associated with lower mortality from total stroke (HR 0.68) and ischemic stroke (HR 0.67) — an association with dietary natto, not a trial of nattokinase capsules.

For broader brain-health research, see our Anti-Dementia Stack guide.

💊 Nattokinase vs. Pharmaceutical Blood Thinners

Educational comparison only — NOT a recommendation to substitute

Nattokinase is sometimes compared to prescription anticoagulants like warfarin, aspirin, or clopidogrel. Here's how they differ:

Warfarin works by inhibiting vitamin K-dependent clotting factors (II, VII, IX, X). It prevents new clot formation but doesn't dissolve existing clots. Nattokinase is proposed to act on existing fibrin as well, but that has not been shown in the human studies cited here.

Aspirin irreversibly inhibits COX-1 in platelets, reducing thromboxane A2 and platelet aggregation. Nattokinase is claimed to have anti-platelet activity through a different mechanism; the cited human studies did not measure it.

However, pharmaceutical anticoagulants are far more potent and predictable than nattokinase. They are prescribed for specific clinical indications (atrial fibrillation, mechanical heart valves, post-surgical prophylaxis) where consistent, dose-controlled anticoagulation is critical. Nattokinase has not been validated as a substitute for prescription anticoagulants in these high-risk scenarios.

🤝 Can You Take Both?

Many supplements combine nattokinase + serrapeptase in a single product ("systemic enzyme" formulas). The rationale is complementary mechanisms: nattokinase for clot dissolution and cardiovascular protection, serrapeptase for inflammation and tissue debris clearance.

While this combination is widely used, there is limited clinical data on the specific combination. That rationale has not been tested here, and if you're taking blood thinners, combining enzyme products calls for extra caution. As always, consult a physician before stacking proteolytic enzymes with anticoagulant medications.

📐 Understanding FU (Fibrinolytic Units)

Nattokinase potency is measured in FU — fibrinolytic units. This measures the enzyme's actual biological activity (how much fibrin it can dissolve), not just the weight of the powder. This is similar to how other enzymes are standardized by activity rather than mass.

The Japan Nattokinase Association (JNKA) has established testing protocols to ensure consistent FU measurement across products.

When buying nattokinase, always check the FU count, not just the milligram weight. A capsule with 2,000 FU is more potent than a heavier capsule with 1,000 FU. The activity is what matters.

🧮 Quick Reference

Standard capsule: 2,000 FU   Plaque study: 10,800 FU/day (single study)   Empty stomach (label advice)

Need help calculating your stack doses? Try our Dosing Calculator.

Additional Safety Considerations

• Bleeding disorders: As a precaution, people with hemophilia, von Willebrand disease, or other bleeding disorders should avoid nattokinase unless a clinician who knows their condition advises otherwise. No study cited here tested it in these groups; the caution follows from its fibrinolytic activity.
• Pregnancy & breastfeeding: Insufficient safety data. Avoid nattokinase during pregnancy and lactation unless specifically directed by a physician.
• Low blood pressure: Nattokinase lowered blood pressure in trials and may cause excessive drops in people with already-low BP. Monitor symptoms (dizziness, lightheadedness).
• GI upset: The cited studies that reported on safety recorded no noticeable adverse effects (PMID 36072877) and no adverse drug reactions (PMID 34199189), but neither was designed to profile side effects. If stomach discomfort or other new symptoms appear, stop and talk to a clinician.
• Soy allergy: Nattokinase is derived from soy fermentation. While the enzyme itself is highly purified, trace soy proteins may be present. Individuals with severe soy allergies should exercise caution or choose soy-free formulations (some manufacturers produce nattokinase via non-soy fermentation substrates).

1. Chen H, Chen J, Zhang F, et al. Effective management of atherosclerosis progress and hyperlipidemia with nattokinase: A clinical study with 1,062 participants. Front Cardiovasc Med. 2022;9:964977. PMID 36072877 · Note: industry-funded (Sungen Bioscience, Sinopharm), not placebo-controlled, carries a published erratum (Front Cardiovasc Med. 2022;9:1076420).
2. Li X, Long J, Gao Q, et al. Nattokinase Supplementation and Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Rev Cardiovasc Med. 2023;24(8):234. PMID 39076715 · 6 RCTs, n=546; pooled SBP −3.45 / DBP −2.32 mmHg.
3. Kim JY, Gum SN, Paik JK, et al. Effects of nattokinase on blood pressure: a randomized, controlled trial. Hypertens Res. 2008;31(8):1583-1588. PMID 18971533
4. Nagata C, Wada K, Tamura T, et al. Dietary soy and natto intake and cardiovascular disease mortality in Japanese adults: the Takayama study. Am J Clin Nutr. 2017;105(2):426-431. PMID 27927636
5. Cesarone MR, Belcaro G, Nicolaides AN, et al. Prevention of venous thrombosis in long-haul flights with Flite Tabs: the LONFLIT-FLITE randomized, controlled trial. Angiology. 2003;54(5):531-539. PMID 14565628
6. Gallelli G, Di Mizio G, Palleria C, et al. Data Recorded in Real Life Support the Safety of Nattokinase in Patients with Vascular Diseases. Nutrients. 2021;13(6). PMID 34199189