What Is Nattokinase?

Nattokinase is a natural enzyme from natto, a Japanese fermented soybean dish.

People take nattokinase supplements to support healthy blood flow, normal blood pressure, and overall heart and circulation health.

You could eat natto, but it has a strong smell and sticky texture. Many people do not like it. So supplements give you a measured, easy dose in a small capsule.

Is Nattokinase Healthy? Benefits, Risks, and Safe Dosage Guide

Is Nattokinase Really Healthy?

For many adults, nattokinase can be helpful. It may support:

Healthy circulation
Normal blood pressure
Balanced clot breakdown (fibrinolysis)

Studies suggest nattokinase helps your body break down fibrin, a protein that helps form blood clots. This can support smoother blood flow and healthy arteries.

But nattokinase also thins the blood, so it is not right for everyone.

Ask yourself: Do I take blood thinners, have bleeding problems, or plan surgery soon?

If yes, talk to your doctor before you use it.

Key Benefits in Simple Terms

Research is still growing, but early human studies suggest three main benefits.

First, better blood flow. Nattokinase helps your body clear fibrin, which can keep blood moving more freely.

Second, support for normal blood pressure. Some trials show small but real reductions in blood pressure when people take nattokinase daily for weeks.

Third, healthy clot balance. Your body is always making and breaking tiny clots. Nattokinase helps keep this balance in a normal range.

So, nattokinase is not a cure or magic pill, but it can be one more tool, along with walking, less sitting, and a simple, heart‑healthy diet.

Who Should Avoid Nattokinase?

Because it can thin your blood, you should be careful.

You should avoid nattokinase or get medical advice first if you:

Take prescription blood thinners like warfarin, apixaban, rivaroxaban, or heparin
Take daily aspirin or high‑dose fish oil for your heart
Have a known bleeding disorder or very low platelets
Just had, or will soon have, major surgery or dental work
Recently had a stroke, serious injury, or major internal bleeding
Are pregnant or breastfeeding

If you see easy bruising, nosebleeds, or bleeding that will not stop, stop using it and get help quickly.

Natto vs Nattokinase Supplements

You can get nattokinase from natto or from supplements.

Natto is a traditional food. It gives you nattokinase, plus probiotics and vitamins. A small pack of natto, around 50 grams, can provide enzyme levels similar to those of a standard supplement. But the smell is strong, and the texture is stringy and sticky. Many people find it hard to eat every day.

Supplements, on the other hand, provide a precise dose in a single capsule. They are easy to take, easy to pack, and much more neutral in taste. If you do not like natto or cannot find it in your local stores, a capsule is the practical option.

Always check the strength in FU (Fibrinolytic Units) and aim for about 2,000 FU per daily serving, not just a “mg” number

Look for NSK‑SD® or clearly non‑GMO natto on the label for a clinically studied, reliable form of nattokinase

Pick products without added Vitamin K2 unless your doctor specifically wants K2 in your routine

Choose clean, simple formulas that are third‑party tested, made in a cGMP facility, and free from unnecessary fillers, colors, or preservatives

Read the safety warnings carefully and avoid brands that do not mention bleeding risks or drug interactions

How Much Nattokinase Should You Take?

Most high‑quality supplements give 2,000 FU (Fibrinolytic Units) per day. That is the standard daily dose used in many products.

For beginners, start with 2,000 FU once a day. Follow the label: usually one capsule daily, with or between meals.

If you miss a dose, do not double the next one. Just continue normally. Remember, FU matters more than mg. Two capsules can both say “100 mg,” but if one gives 2,000 FU and the other gives 400 FU, they are very different in strength.

If the label does not show FU, it is better to choose another brand.

Why the Right Nattokinase Supplement Matters

Not every nattokinase product is safe or effective. Some use weak enzyme strength, hide the FU number, or add cheap fillers, colors, or preservatives.

That matters because nattokinase influences clotting and blood flow. Bad quality can mean a product that does little, or one that is too risky. Careful choice helps you achieve real benefits with less risk.

How to Choose a Safe and Effective Nattokinase

First, check the FU dose. Look for 2,000 FU per serving. Make sure the label clearly says “2,000 FU.” If you only see “100 mg of nattokinase” with no FU, skip it.

Next, look for NSK‑SD® or at least a clearly stated non‑GMO natto source. NSK‑SD® is a clinically studied form of nattokinase. It is made from non‑GMO soybeans and standardized for reliable enzyme activity. It is also typically free of vitamin K, which is important if you are managing clotting and working with your doctor.

Then check whether the formula contains Vitamin K2. Vitamin K2 is useful for bone and arterial health, but it can interact with certain blood thinners. If your main goals are circulation and heart support, and you use any heart or blood pressure medicine, choose nattokinase without added K2, unless your doctor prefers it.

Also, scan the ingredients list. A good nattokinase supplement will have clean ingredients, no artificial colors, no fake flavors, and minimal fillers. Some people also want it to be vegan, gluten‑free, and dairy‑free.

Finally, check for quality testing and safety warnings. Look for “cGMP” on the label, which means the product was made under good manufacturing rules. Look for “third‑party tested” to indicate that an independent lab tested the product. Good brands are honest about who should not take nattokinase and tell you to talk to your doctor if you use other medicines.

When you pick a nattokinase supplement for heart health and circulation support, look for these traits together, not just one:

Clear 2,000 FU per serving
NSK‑SD® or a clearly non‑GMO natto source
No added Vitamin K2, unless your doctor wants it
Clean label and strong allergen info
Mentions cGMP and quality testing
Honest safety warnings about bleeding and drug interactions

Recommended Nattokinase Supplements (NSK‑SD®)

Here are two examples that match these beginner‑friendly nattokinase guidelines and use NSK‑SD® nattokinase.

Himalaya NSK‑SD Nattokinase, 100 mg, 60 Capsules

100 mg NSK‑SD® nattokinase (2,000 FU) per capsule for daily circulation support*
Once‑daily, vegan capsule that fits easily into your morning or evening routine
From fermented soybeans; free from gluten and dairy for sensitive stomachs
Made in a cGMP‑certified facility and tested for identity, quality, and potency
No animal gelatin and no magnesium stearate or non‑plant fillers

If you make a purchase via our links, Ouspan earns a commission at no additional cost to you

Klaire Labs / SFI Health Nattokinase NSK‑SD, 60 Capsules

Clinically studied NSK‑SD® nattokinase standardized by fibrin activity units*
Designed to support fibrinolytic activity, circulation, and healthy clot balance*
Made from non‑GMO soybean isolates fermented by Bacillus subtilis natto
Free of vitamin K, so it focuses only on the enzyme’s circulatory support*
Allergen‑friendly: free of milk/casein, eggs, fish, shellfish, tree nuts, peanuts, wheat, gluten, and yeast
Contains no artificial colors, flavors, or preservatives, for a clean label

If you make a purchase via our links, Ouspan earns a commission at no additional cost to you

Start simple. Start slow. Pay attention.

Begin with one capsule per day, around 2,000 FU, unless your doctor gives a different plan. Take it at the same time each day, maybe with your breakfast or evening routine, so it is easy to remember.

Notice how your body feels over a few weeks. Are your legs less heavy after sitting? Do you feel steadier energy with walks and light movement? At the same time, watch for any signs of easy bruising or bleeding.

If you use blood thinners, heart meds, or daily aspirin, or you have any heart or clotting history, talk to your doctor before you start. Show them the product label, including the FU amount and the NSK‑SD® name, so they can give you a clear answer.

Nattokinase can be a simple, useful tool for healthy circulation and heart support. But your safety, dose, and doctor’s advice matter more than any supplement.