6 Best Nattokinase Supplements [Update 2025]

Many people shopping for nattokinase supplements tend to focus only on the number of milligrams (mg) listed on the product label. However, this is a common mistake that can carry hidden risks.

In reality, the milligram amount does not accurately reflect the biological activity of the enzyme. A product might contain 100 mg of nattokinase, but its enzyme activity—meaning its ability to break down fibrin—could be very low or even negligible.

What truly matters is the enzyme’s activity level, which is measured in FU (Fibrinolytic Units). FU indicates how effectively the enzyme can dissolve fibrin, a key component in blood clot formation.

Experts recommend that each capsule provide an ideal dose of 2,000 FU to support cardiovascular health. If you only look at the mg content without knowing how many FUs the product delivers, you could be taking a form of nattokinase that’s nearly inactive.

Even more concerning, many products on the market lack third-party testing or fail to clearly disclose their actual FU levels. This makes it easy for consumers to be misled by marketing claims, potentially using low-quality supplements over a long period without seeing any real health benefits.

In some cases, using substandard nattokinase could negatively affect blood clotting—especially for those already taking anticoagulant medications.

That’s why, before purchasing any nattokinase supplement, it’s essential to carefully read the product label, check for the FU amount, and choose brands that are verified by reputable third-party labs. This article will help you avoid common pitfalls and choose a product that is truly effective and safe for your health.

Comparison Table of the Best Nattokinase Supplements

How Do We Choose the Best Nattokinase Supplements?

Nattokinase Dosage (FU – Fibrinolytic Units)

To choose a high-quality nattokinase supplement, the first factor to consider is the FU content (Fibrinolytic Units), which measures the enzyme activity of nattokinase. One FU is defined as the amount of enzyme that increases absorbance at a wavelength of 275 nm by 0.01 units per minute [4].

According to the Japan Nattokinase Association, the recommended daily dosage is 2,000 FU, which is approximately 100 mg of nattokinase [12]. This dosage has been studied and shown to be effective in supporting cardiovascular health.

In one human study, participants took 2,000 FU (about two capsules) daily for eight weeks. The results showed no significant changes in body weight, heart rate, or uric acid levels. However, there was a significant reduction in blood clot-related markers such as fibrinogen, factor VII, and factor VIII in plasma [4].

This suggests that a dose of 2,000 FU may help promote healthy circulation and reduce the risk of blood clot formation.

That’s why it’s essential to choose a product with the correct FU level. If a supplement contains less than the recommended amount, its effectiveness may be limited [12].

On the other hand, taking a product with too high an FU level without medical advice can increase the risk of bleeding, especially for those using blood thinners [4]. For this reason, always check the label carefully to ensure the FU dosage is clearly stated and aligns with your personal health needs.

Purity and Enzyme Source

High-quality nattokinase is typically extracted from natto, a traditional Japanese fermented soybean dish made using the Bacillus subtilis bacterium [9]. This is a natural source of the enzyme and is considered the key active component responsible for natto’s health benefits, such as supporting circulation and reducing the risk of blood clot formation [2].

Notably, many nattokinase products are processed to remove vitamin K2, a natural clotting factor present in natto [4]. This is especially important for individuals taking blood-thinning medications, as vitamin K2 may reduce the effectiveness of these drugs.

Therefore, when selecting a product, it is advisable to choose one that clearly states “vitamin K2-free” to ensure safety and suitability for your health needs.

The production of nattokinase typically involves microbial fermentation using strains of Bacillus spp., which helps ensure enzyme purity and activity [5]. A high-quality product will transparently disclose the source of the enzyme and the manufacturing process, giving users confidence in its safety and effectiveness.

Safety Certifications and Transparency

To ensure quality and safety, consumers should look for products that carry reputable certifications.

Certifications like NSF Certified, GMP-compliant (Good Manufacturing Practices), Non-GMO, and free from common allergens such as gluten, soy, and dairy are all signs that the product was made to high standards. These certifications not only ensure quality but also reflect the manufacturer’s transparency in providing product information.

Choosing a supplement with clear certifications helps minimize the risks associated with contaminants or unwanted ingredients. For individuals with sensitivities or those following specific dietary guidelines, labels like “gluten-free” or “non-GMO” are especially important when selecting a supplement.

Formulation and Bioavailability

The formulation and bioavailability of nattokinase play a critical role in ensuring the product's effectiveness. Nattokinase is typically produced through either liquid or solid-state fermentation, then extracted and purified for use in convenient capsule or tablet forms [7, 10].

To enhance stability and absorption, some manufacturers apply advanced techniques like microencapsulation with γ-polyglutamic acid or use phytosterol-based liposomes to protect the nattokinase enzyme [3, 5]. These technologies help preserve the enzyme's activity in the harsh environment of the digestive system.

In terms of absorption, nattokinase has been shown to remain stable in the digestive tract, withstanding temperatures up to 50°C and a pH range of 6 to 12 [8]. This allows the enzyme to be absorbed into the bloodstream either in its intact form or as active metabolites, supporting its fibrinolytic effects [4].

However, in highly acidic environments or at temperatures above 60°C, nattokinase activity may be significantly reduced [1, 8]. Therefore, products formulated with protective technologies are generally more effective.

Brand Reputation and Customer Reviews

Brand reputation and customer feedback are key indicators when evaluating nattokinase product quality. Established brands, especially those specializing in cardiovascular health or traditional Japanese fermented foods, tend to be more reliable.

It’s advisable to prioritize products with ratings above 4 stars on platforms like Amazon, iHerb, or Walmart, and supported by hundreds or thousands of user reviews.

Positive reviews often highlight benefits such as supporting healthy blood circulation, helping maintain normal blood pressure, and promoting the body’s natural ability to manage blood clotting.

However, it’s important to pay attention to negative reviews, especially those mentioning side effects like digestive discomfort or concerns about product purity. Brands that are transparent about their ingredients, manufacturing process, and have clear certifications generally earn higher consumer trust.

Price and Dosage Value

Lastly, price and dosage value are important factors when choosing a suitable product. A high-quality nattokinase supplement typically costs between $0.07 to $0.50 per dose (equivalent to 2,000 FU or 100–200 mg) [based on market data].

Pricing can vary depending on the source of the enzyme, extraction technology, and additional ingredients like serrapeptase or vitamin K2.

Consumers should compare prices based on standardized FU dosage rather than just milligram content, as FU better reflects the enzyme’s activity. Capsules are often preferred for their convenience and effective absorption. Be cautious of low-priced products that offer very low enzyme units or weak potency, as they may not deliver the desired benefits.

Whether to choose a pure nattokinase product or a blend with other ingredients also impacts the product's value. If your goal is to use nattokinase alone, look for supplements without added enzymes or vitamins to optimize cost and effectiveness.

6 Best Nattokinase Supplements 2025

Double Woods Nattokinase Supplement 4,000 FU Servings - 60 Servings | $19.95

Review

When looking for a reliable nattokinase supplement, Double Wood’s Nattokinase Supplement stands out with a dosage of 4,000 FU per serving (200 mg, equivalent to two 100 mg/2,000 FU capsules), offering 120 capsules for a 60-day supply.

It is extracted from Japanese natto – a traditional fermented soybean dish – and is designed to support cardiovascular health, improve circulation, and promote vascular wellness. This product is ideal for those who want to take Nattokinase alone without combining it with multiple other ingredients.

In terms of health benefits, many customers report that the product helps maintain normal levels of C-reactive protein, which contributes to heart health. Notably, some users have experienced enhanced overall well-being when combining this supplement with Double Wood's liquid 5-HTP.*

Manufactured in the USA, the product is certified vegan, gluten-free, and non-GMO, making it suitable for various dietary needs. This product also clearly provides a Certificate of Analysis (COA), confirming that the capsules meet the disintegration time requirement (no more than 30 minutes). Additionally, it meets standards for purity and hygienic safety, ensuring effective and reliable use.

With over 2,000 reviews on Amazon, it holds the Amazon’s Choice badge, with more than 90% of ratings being 4 or 5 stars. Users often appreciate the easy-to-swallow capsules and the quality of the Japanese natto source.

However, pain relief results vary: while some users report strong anti-inflammatory effects, others experience mild stomach discomfort.*

Pros

• Amazon’s Choice badge with over 90% positive reviews from more than 2,000 customers, demonstrating strong market trust and popularity

• Third-party tested for quality, ensuring safety and transparency in manufacturing

• Naturally sourced from Japanese natto, vegan-friendly, gluten-free, and non-GMO

Cons

• Some users report mild stomach pain after use, which may cause discomfort for those with sensitive digestive systems*

• Priced at $19.95 for 60 servings, it may seem costly, especially since each capsule contains only 2,000 FU—lower than the 4,000 FU prominently advertised on the label, potentially leading to confusion*

• A few cases of constipation have been reported, so users should monitor their body's response when starting the supplement*

Now Foods Nattokinase 100 mg Veg Capsules 2000FU - 60 Servings| $29.99

Review

In the search for a high-quality nattokinase supplement, NOW Foods Nattokinase 100 mg Veg Capsules stands out with a dosage of 2,000 FU (100 mg) per capsule, offering a convenient 60-serving supply. Beyond dosage, the product also emphasizes quality and dietary compatibility.

When it comes to quality, the product uses non-GMO soy and contains no vitamin K, making it suitable for vegetarian, vegan, kosher, and keto diets.

Manufactured in a GMP-certified facility in the USA, NOW Foods ensures the product is free from common allergies like gluten, dairy, eggs, or tree nuts. With over 80% positive reviews on Amazon, users appreciate its ease of use and compatibility with various dietary needs.

One customer named Alisha shared a positive experience: “Does what it’s intended to do. Supports healthy blood flow and may contribute to better blood pressure management.”*

NOW Foods, a family-owned brand since 1968, has built a solid reputation through its commitment to quality and transparency. However, it’s worth noting that natural color variation may occur, which does not affect effectiveness but may be surprising to some users.

Pros

• Uses non-GMO soy, ensuring a natural and high-quality source of nattokinase enzyme

• GMP-certified with manufacturing and quality control processes based in the USA, offering strong reliability

• Free from gluten, dairy, eggs, and common allergens; suitable for vegetarian, vegan, kosher, and keto diets

Cons

• Does not provide test results upon customer request, raising concerns about transparency in quality verification*

• Some users have experienced intense body tremors after a few days of use, suggesting caution is needed when starting*

• Requires consulting a doctor if taken alongside blood thinners to avoid interactions, which may be inconvenient for some users*

Vinatura Lumbrokinase Nattokinase Serrapeptase 2000FU - 60 Servings | $26.89

Review

If you’re looking for a circulation support supplement with a unique formula, Vinatura Lumbrokinase Nattokinase Serrapeptase is a standout option. Each bottle provides 60 capsules, with each serving containing 2,000 FU of nattokinase (100 mg), 800,000 units of lumbrokinase, 125,000 SPU of serrapeptase, along with added rutin and beetroot—offering comprehensive support for cardiovascular and circulatory health.

The microbial test results indicate that the product meets safety standards, with no detection of harmful microorganisms such as E. Coli or Salmonella. Additionally, the total counts of aerobic bacteria, yeast, and mold are all within permissible safety limits, ensuring hygienic quality.

All parameters were analyzed using AOAC methods, a trusted international standard in the food and pharmaceutical industries. The product was also tested for heavy metals, and the clear and transparent disclosure of these results demonstrates that the product is strictly controlled for purity and safety.

What makes this product stand out is its blend of three natural enzymes, each playing a distinct role. Nattokinase, extracted from Japanese natto, supports natural blood clotting and fibrinolytic processes. Studies from Japan suggest its benefits in promoting healthy blood flow and vascular function.

Lumbrokinase, derived from earthworms and widely used in traditional Chinese medicine, helps break down fibrinogen—a protein that can accumulate in blood vessels. Serrapeptase, an enzyme from bacteria found in silkworms, assists in protein breakdown and promotes vascular health.

With over 80% positive reviews on Amazon and an Amazon’s Choice badge, the product has gained strong user approval. One customer, Ang, shared: “I have been having to take natto kinase for my blood flow for many years now (I’m 53). Some work well, some I have felt like I was ripped off. This one works exceptionally well! I reordered it because I’ve had no flow issues since starting this one.”*

Additionally, the product is made in a cGMP-certified facility in the USA and is third-party tested for purity. It contains no soy, gluten, dairy, or common allergens, making it suitable for various dietary needs.

Pros

• Amazon’s Choice certification with over 80% positive reviews, confirming user trust and popularity*

• Manufactured in a cGMP-certified facility in the USA, third-party tested for quality and purity

• Unique formula combining 2,000 FU nattokinase, 800,000 LU lumbrokinase, 125,000 SPU serrapeptase, plus rutin and beetroot for enhanced effectiveness

• Free from soy, gluten, dairy, and allergens, suitable for various diets

• Passed microbial and heavy metal tests to ensure safety and purity.

• Tested using trusted AOAC methods for hygienic and quality assurance.

Cons

• Priced at $26.89 for 60 servings, which may be considered slightly expensive compared to some standalone nattokinase products*

Doctors Best Nattokinase Supplements 2000 FU - 90 Servings | $14.99

Review

For those looking to supplement with Nattokinase at an affordable price, Doctors Best Nattokinase Supplements is a solid option to consider. Each bottle contains 90 vegetarian capsules, with each capsule providing 2,000 FU of nattokinase extracted from Japanese natto.

In terms of quality, the product is manufactured in a cGMP-compliant facility, uses non-GMO soy, and excludes vitamin K2—making it suitable for individuals who need to avoid clotting factors. It’s also third-party tested to ensure purity and consistency. Backed by the Amazon’s Choice badge and many positive reviews, this supplement is well-received.*

Another reason customers appreciate this product is that Doctor’s Best has thoughtfully prepared a Nattokinase Fact Sheet and included it alongside the product information. This document is compiled from various research sources and provides an overview of Nattokinase—its origin (studied since the 1980s by Dr. Hiroyuki Sumi), its key benefits, clinical evidence, and safety profile.

While simple, this effort is especially valuable for those who are new to Nattokinase—and even for more discerning customers—who want a deeper understanding before deciding to use it.

One customer, Sue, commented: “Good deal. Hoping it helps keep my arteries clearer. Hard to know for sure if it's working but I don't have as much pain in my legs at night. Took a long time to help, like almost a year, but the bottles have plenty of capsules, one per day.”*

Doctors Best, with over 30 years of experience in the supplement industry, is known for its science-based formulas. This product reflects the brand’s commitment to supporting circulatory health naturally and sustainably.

Pros

• Amazon’s Choice certified, showing high user trust and popularity

• Manufactured in a cGMP facility, third-party tested for quality and purity

• Trusted brand with over 30 years of experience, non-GMO, vegan, and vitamin K2-free—suitable for diverse needs

• Includes a well-researched fact sheet that helps customers understand Nattokinase’s origin, benefits, and safety.

Cons

• The absence of vitamin K2 may not suit users who prefer it included*

• Contains maltodextrin, a high-glycemic ingredient that could be concerning for individuals sensitive to sugar*

• Some users report headaches and night sweats—monitor your body’s response when using*

Horbäach Nattokinase Supplement 4000 FU - 75 servings | $9.99

Review

Horbäach Nattokinase Supplement is an effective nattokinase product offered at an affordable price. Each bottle contains 150 capsules, providing 75 servings with a dose of 4,000 FU nattokinase (2 capsules per serving), extracted from natto—a traditional Japanese fermented soybean dish.

The nattokinase in this product supports the body’s natural ability to break down blood clots, promoting better blood circulation. Many users report significant reductions in chest pain and brain fog, and some even notice faster effects compared to standard blood thinners.

However, some customers mention that the product does not produce clear results in lowering blood pressure, which should be considered depending on individual needs.*

Regarding quality, the supplement is free from gluten, wheat, dairy, lactose, artificial flavors, and preservatives, and does not use genetically modified ingredients. Manufactured in GMP-certified facilities in the USA, Horbäach complies with strict FDA, NLEA, and DSHEA regulations and holds USDA organic certification.

With over 90% positive reviews on Amazon and the Amazon’s Choice badge, users appreciate its easy-to-swallow capsules, reliable quality, and clear health benefits.*

Horbäach, with more than 40 years of experience in the supplement industry, is committed to delivering pure and effective products. Their closed manufacturing process, from ingredient selection to quality testing, makes this supplement an attractive option for those seeking blood circulation support at a reasonable cost.

Pros

• Amazon’s Choice certified with over 90% positive reviews, showing high user trust and popularity

• Produced in GMP-certified facilities, complies with FDA regulations, and holds USDA organic certification, ensuring high quality

• Competitively priced at only $9.99 for 75 servings, free from gluten and common allergens, suitable for vegan diets

Cons

• Lack of third-party testing raises concerns for some users about transparency in quality verification*

• Does not lower blood pressure effectively for some users, so it may not meet all expectations*

• A few users report nausea after use, so monitoring your body’s reaction when starting is advised*

Pure Prescriptions Max Strength Nattokinase 2000 FU - 180 Servings | $49

Review

Pure Prescriptions Max Strength Nattokinase is a product worth exploring. With 180 capsules, each providing 2,000 FU of NSK-SD® nattokinase extracted from natto—a traditional Japanese fermented soybean dish—this product offers strong support for blood circulation and cardiovascular health, especially suitable for people who need to avoid vitamin K.

NSK-SD® nattokinase stands out as a fibrinolytic enzyme that helps maintain healthy blood flow and effectively supports the circulatory system. Users report noticeable improvements in circulation and cardiovascular well-being after about three months of use.*

A customer, Amanda D., shared: “Love the product! My husband and I have been using it for about 3 months now. BP has reduced, and circulation has definitely improved. Shipping was faster than expected too so that’s great.”*

Regarding quality, the product uses the Cardiokinase formula with superior enzyme activity (20,000 FU/g), which is over 200% more effective than regular nattokinase products.

With over $1 million invested in safety research, the product ensures it contains no vitamin K2 (below 0.1 ppm), harmful bacteria. Pure Prescriptions, a family-owned company with more than 24 years of experience, proudly offers a product endorsed by Dr. Sumi—the scientist who discovered nattokinase—and awarded by Nutrition Business Journal.

The combination of a premium formula, strict testing, and trusted brand makes this product a reliable choice for those who want to care for their circulatory health in a scientific and safe way.

Pros

• Uses NSK-SD® nattokinase with high activity of 20,000 FU/g, over 200% more potent than regular products

• Endorsed by Dr. Sumi and awarded by Nutrition Business Journal, confirming credibility and quality

• Produced by a family-owned company with over 24 years of experience, committed to transparency and excellent customer service

Cons

• The bottle is larger than the amount of product inside, which can be inconvenient for storage or travel*

• Some users report longer-than-expected shipping times, affecting the shopping experience*

Conclusion

Nattokinase is an enzyme with great potential to support heart health, especially due to its fibrinolytic ability and support for blood circulation. However, not all products labeled “nattokinase” are equally effective. Differences lie in purity, FU activity, and transparency of testing.

By comparing important factors such as enzyme origin, standard FU dosage, safety certifications, and user reviews, you can choose a product that fits your health goals.

Finally, if you are still unsure between options or want to optimize results, consider your specific goal: Do you need nattokinase alone, or are you looking for a powerful combined formula like a multi-enzyme blend? The right choice will help you invest wisely in long-term cardiovascular health.