Looking to keep your blood flowing smoothly and give your cardiovascular system targeted support? Source Naturals Nattokinase 100 mg delivers 2,000 Fibrin Units (FU) of pure, clinically validated NSK-SD®—the world's most researched form of nattokinase. Derived from traditional Japanese fermented soybeans (natto), this specialized systemic enzyme helps your body maintain healthy blood viscosity, vascular elasticity, and microvascular flow without unnecessary additives.
Quick Product Highlights
✓Clinically Active Dose: Delivers 100 mg (2,000 Fibrin Units) of patented NSK-SD® nattokinase per single-capsule serving.
✓Circulatory Clearing Power: Assists the body's natural fibrinolytic (clot-dissolving) processes to encourage effortless arterial blood flow.
✓Patented Vitamin K2 Removal: Carefully filtered using a proprietary process to remove virtually all Vitamin K2, preventing unwanted interactions with blood-thinning balance.
✓Systemic Protection: Works throughout your entire vascular tree—from major arteries down to delicate microcapillaries in the extremities, brain, and eyes.
✓Pure & Clean: Free of yeast, gluten, wheat, dairy, eggs, artificial colors, artificial flavors, and preservatives.
How Nattokinase Works: The Science of Blood Flow in Plain English
To understand why nattokinase is such a breakthrough nutrient, think of your vascular system like a vast network of highways. Throughout your life, your body relies on an insoluble protein called fibrin. When you get a cut or scrape, fibrin forms a sticky, web-like mesh that traps platelets to create a protective scab—a vital survival mechanism.
However, as we age, encounter chronic stress, or deal with low physical activity, the body can produce excess fibrin inside circulating blood vessels. Excess fibrin makes blood thicker, stickier, and more sluggish—much like debris cluttering the lanes of a busy freeway. This increases cardiovascular resistance, forcing your heart to work harder to pump blood through narrow capillaries.
Nattokinase is a systemic fibrinolytic enzyme, meaning it operates inside your bloodstream rather than merely breaking down food in your stomach. It performs a unique "double-action" cleanup:
Direct Action: Nattokinase directly cuts through and breaks down cross-linked fibrin protein threads, reducing sludgy blood build-up without disturbing normal, healthy clotting factors.
Indirect Action: It signals your body to increase its own clot-clearing machinery. Specifically, it stimulates the release of tissue plasminogen activator (t-PA) and boosts the conversion of inactive prourokinase into active urokinase, enhancing your natural endogenous enzyme defense.
Blood Pressure Balance: Nattokinase helps naturally inhibit angiotensin-converting enzyme (ACE) activity and balances plasma renin, easing tension across arterial walls to encourage smooth blood pressure control.
Clinically Grounded Research: What Human Studies Reveal
When choosing cardiovascular supplements, clinical evidence matters. Nattokinase is backed by dozens of peer-reviewed clinical trials investigating its safety, bioavailability, and physiological actions:
1. Rapid Clot-Dissolving and Anti-Thrombotic Action (Human Clinical Data)
In a landmark double-blind, placebo-controlled crossover study published in Scientific Reports, researchers administered a single oral dose of 2,000 FU nattokinase to healthy human volunteers. Blood samples tracked over 48 hours demonstrated that oral nattokinase significantly enhanced fibrin and blood clot breakdown products (such as D-dimer) within 6 to 8 hours post-ingestion.
Reference: Kurosawa Y, Nirengi S, Homma T, et al. A single-dose of oral nattokinase potentiates thrombolysis and anti-coagulation profiles. Scientific Reports. 2015;5:11601. [PMID: 26109079]
2. Blood Pressure and Renin Activity Regulation
In an 8-week randomized, double-blind, placebo-controlled clinical trial published in Hypertension Research, 86 human subjects aged 20 to 80 with elevated blood pressure took 2,000 FU of nattokinase daily. The nattokinase group demonstrated a statistically significant reduction in both systolic blood pressure (-5.55 mmHg net) and diastolic blood pressure (-2.84 mmHg net), accompanied by a favorable decrease in plasma renin activity.
Reference: Kim JY, Gum SN, Paik JK, et al. Effects of nattokinase on blood pressure: a randomized, controlled trial. Hypertension Research. 2008;31(8):1583-1588. [PMID: 18971533]
3. Vascular Health and Cardiovascular Risk Markers
A multicenter North American randomized clinical trial published in Integrated Blood Pressure Control examined subjects taking nattokinase over 8 weeks. Researchers observed meaningful decreases in blood pressure alongside a significant reduction in von Willebrand factor (vWF)—a recognized biomarker for arterial inflammation and clotting risk.
Reference: Jensen GS, Lenninger M, Ero MP, Benson KF. Consumption of nattokinase is associated with reduced blood pressure and von Willebrand factor, a cardiovascular risk marker. Integrative Blood Pressure Control. 2016;9:95-104. [PMID: 27785095]
4. Long-Term Arterial Plaque and Lipid Management (1,062 Patients)
A large 12-month clinical study published in Frontiers in Cardiovascular Medicine evaluated 1,062 participants to observe the impact of daily nattokinase on arterial thickness. The findings showed sustained improvements in carotid artery intima-media thickness (CCA-IMT) and carotid plaque size, confirming nattokinase's safety profile over prolonged periods.
Reference: Chen H, Chen J, Zhang F, et al. Effective management of atherosclerosis progress and hyperlipidemia with nattokinase: A clinical study with 1,062 participants. Frontiers in Cardiovascular Medicine. 2022;9:964977. [PMID: 36172238]
The NSK-SD® Difference: Why Source Naturals Leads in Quality
Not all nattokinase supplements are created equal. Raw natto food contains high amounts of Vitamin K2. While Vitamin K2 is wonderful for bone density, it is also the nutrient your liver uses to produce clotting factors. If you take a nattokinase product that retains raw Vitamin K2, you run the risk of blunting its blood-thinning and fibrin-clearing effectiveness.
Source Naturals solves this issue by exclusively utilizing NSK-SD® (Natural Super Kinase-Sprayed Dried), produced by the pioneer of nattokinase science, Japan Bio Science Laboratories (JBSL):
Patented Vitamin K2 Extraction: NSK-SD® uses a patented filtration method that reduces Vitamin K2 to less than 0.1 parts per million (virtually 100% Vitamin K2-free).
Standardized Enzymatic Potency: Every single capsule is standardized to deliver precisely 2,000 Fibrin Units (FU), guaranteeing reliable activity batch after batch.
Authentic Non-GMO Fermentation: Fermented exclusively with non-GMO soybeans and a proprietary strain of Bacillus subtilis var. natto.
Safety Authenticated: Recognized by the Japan NattoKinase Association (JNKA) and backed by extensive toxicological safety evaluations submitted to the U.S. FDA.
How to Take Source Naturals Nattokinase for Maximum Absorption
Because nattokinase is a protein-cleaving enzyme, when you take it is just as important as what you take:
Crucial Rule: Always take Nattokinase on an empty stomach!
If taken with meals, nattokinase will spend its enzymatic energy digesting proteins from your food (like meat, dairy, or beans) inside the stomach. When taken on an empty stomach with a full glass of water, it passes through the stomach intact and enters the small intestine, where it is absorbed systemically into the bloodstream to clean circulatory pathways.
Suggested Use: Take 1 capsule three times daily on an empty stomach with 8 ounces of water, or as directed by your healthcare professional. For daily maintenance, many individuals begin with 1 capsule (2,000 FU) daily.
Ideal Timing: Take your dose at least 30 to 45 minutes before a meal, or at least 2 hours after finishing a meal.
Bedtime Advantage: Many cardiovascular experts recommend taking one of your doses right before bed. Normal blood circulation naturally slows down while sleeping, making nighttime an optimal window for enzymatic circulatory support.
Safety Precautions, Warnings & Drug Interactions
Because nattokinase possesses potent fibrinolytic and blood-thinning properties, please review these vital health precautions before incorporating it into your routine:
Prescription Blood Thinners (Anticoagulants & Antiplatelets): Do NOT use nattokinase without strict medical supervision if you are currently taking warfarin (Coumadin®), heparin, clopidogrel (Plavix®), apixaban (Eliquis®), rivaroxaban (Xarelto®), or daily high-dose aspirin. Combining nattokinase with prescription anticoagulants can compound blood-thinning effects and increase the risk of bruising or bleeding.
Bleeding & Coagulation Disorders: Do not use if you suffer from bleeding disorders such as hemophilia, active stomach ulcers, or a history of hemorrhagic stroke.
Blood Pressure Medications: Because nattokinase helps ease arterial tension and may lower blood pressure, monitor your blood pressure closely if you take antihypertensive medications (ACE inhibitors, beta-blockers, or diuretics) to ensure readings do not drop too low.
Upcoming Surgeries & Dental Procedures: Discontinue taking nattokinase at least 14 days (2 weeks) prior to any scheduled surgery or invasive dental procedure to prevent excessive intra- or post-operative bleeding.
Pregnancy & Nursing: Do not use if you are pregnant, planning to become pregnant, or breastfeeding, as clinical safety has not been established in these populations.
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Always discuss supplement changes with your personal physician.
Complete Supplement Facts & Ingredients
VitaNet® believes in 100% label honesty. Below is the full nutritional panel and ingredient declaration for Source Naturals Nattokinase 100 mg (SKU: SN1885):
Supplement Facts
Serving Size: 1 Capsule Servings Per Container: 60
Amount Per Serving
% Daily Value
Nattokinase (NSK-SD®) supplying 2,000 Fibrin Units (FU) of activity
100 mg *
* Daily Value not established.
Other Ingredients: Microcrystalline cellulose, gelatin (capsule), colloidal silicon dioxide (silica), and magnesium stearate.
Allergen Information: Contains soy.
Free From: Contains no yeast, dairy, egg, gluten, or wheat. Contains no sugar, starch, salt, preservatives, or artificial color, flavor, or fragrance.
Frequently Asked Questions (FAQ)
What does "2,000 FU" mean on the nattokinase label?
"FU" stands for Fibrin Units (also called Fibrinolytic Units). Unlike simple milligrams that only measure raw powder weight, FU measures actual biological activity—how effectively the enzyme dissolves fibrin protein in laboratory tests. A standard dose of 100 mg providing 2,000 FU is the exact potency benchmark established in Japanese cardiovascular research.
How is Source Naturals Nattokinase different from eating natto food?
While eating whole natto food provides natural enzymes, it has an intensely pungent, fermented smell, a sticky stringy texture, and an acquired taste. More importantly, whole natto contains exceptionally high levels of Vitamin K2, which promotes blood clotting and makes it inappropriate for individuals monitoring vitamin K intake. Source Naturals uses NSK-SD®, which delivers pure active enzyme with virtually all Vitamin K2 removed.
Why is it essential to take nattokinase on an empty stomach?
Nattokinase is a systemic proteolytic (protein-breaking) enzyme. If you take it with food, it stays in the stomach to digest proteins from your meal. Taking it on an empty stomach (at least 30 minutes before food or 2 hours after) allows it to pass into your intestines intact, where it absorbs into your circulation to clean up vascular fibrin.
Can I take nattokinase if I am already on blood thinners like Warfarin or Eliquis?
No, you should never combine nattokinase with prescription anticoagulants or antiplatelet drugs without express supervision from your physician. Because nattokinase has natural clot-clearing properties, combining it with medications like Coumadin, heparin, Plavix, or Eliquis may excessively thin the blood and elevate the risk of internal bleeding.
How long does it take for nattokinase to start working?
Clinical pharmacokinetic trials show that nattokinase begins enhancing fibrinolytic activity in the bloodstream within 2 to 4 hours, peaking between 6 and 8 hours after consumption. For long-term cardiovascular metrics such as blood pressure balance and arterial elasticity, clinical studies demonstrate optimal outcomes with consistent daily use over 8 to 12 weeks.
Do I need to stop taking nattokinase before surgery or dental work?
Yes. Because nattokinase reduces blood stickiness and helps break down fibrin clots, you should discontinue use at least 14 days before any elective surgery, dental extraction, or invasive medical procedure to allow normal clotting mechanisms to fully stabilize.
The VitaNet® Advantage: Authentic Supplements You Can Trust
When investing in your heart health, product authenticity and freshness matter. VitaNet® has supplied high-integrity dietary supplements to wellness-focused families for over three decades:
✓100% Genuine Source Naturals Products: Sourced directly through verified manufacturing chains. Never counterfeit or diluted.
✓Climate-Controlled Storage: Enzymes are sensitive to heat and moisture. Our climate-regulated warehousing protects enzymatic activity from bottling to delivery.
✓Guaranteed Freshness: High-inventory turnover ensures you receive fresh, sealed bottles with maximum shelf life.
✓Prompt & Reliable Delivery: Orders ship promptly so your wellness regimen never misses a beat.
