Root Cause Cardiology
Your Cardiologist Watches Your Cholesterol.
Almost Nobody Watches Your Fibrin.
FLOW is a two-enzyme formula built for one job: supporting the fibrin balance, blood flow, and vascular calm your cardiovascular system depends on every second of every day.
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Circulation Support
Supports healthy blood flow, normal blood viscosity, and delivery of oxygen and nutrients to every tissue.
Fibrin Balance
Supports the body's own fibrinolytic pathways — the normal housekeeping system that keeps fibrin from accumulating.
Vascular Calm
Supports a healthy inflammatory balance in blood vessels and healthy endothelial function.
You Do Not Have an Aspirin Deficiency
Here is what conventional cardiology gets right: most heart attacks and most strokes are not slow, quiet events. They are sudden ones. A vulnerable area of artery is disturbed, the clotting cascade fires, fibrin lays down a mesh, and blood flow stops. That is the moment everything changes.
Here is what conventional cardiology gets wrong: the answer to that moment is not a lifetime of drugs bolted onto a body nobody bothered to investigate. Your blood is supposed to have a braking system. Plasmin, the body's own clot-dissolving enzyme, is meant to clear fibrin as fast as it forms. That system slows down with age, inflammation, poor sleep, sedentary living, toxic exposure, and a diet built out of things your great-grandparents would not recognize as food.
Too much bad stuff. Not enough good stuff. That is the whole story of cardiovascular disease, and fibrin sits right in the middle of it.
Traditional cultures ate fermented foods rich in fibrinolytic enzymes. Natto, the fermented soybean staple of Japan, is the most studied of them. Almost nobody in the modern world eats anything like it. FLOW is how I put that missing input back into the diet in a form people will actually take.
Dr. Jack Wolfson, DO — Cardiologist since 2002
Two Enzymes. One Job.
FLOW pairs a nattokinase-type fibrinolytic enzyme with a serrapeptase-type proteolytic enzyme. They work on the same problem from two directions.
NattoZimes®
4,516 FU per capsule
A fibrinolytic enzyme blend with nattokinase-equivalent activity, produced by controlled fermentation rather than extracted from soy. It supports the body's normal fibrinolytic activity and healthy blood flow.
At one capsule twice daily you take in 9,032 FU per day. The typical nattokinase supplement on the shelf delivers about 2,000 FU. That gap is deliberate, and it is the reason this formula exists.
Serrazimes®
20,000 units per capsule
A serrapeptase-equivalent proteolytic enzyme from a vegetarian fungal source. Serrapeptase-type enzymes act on excess proteins and cellular debris that the body needs to clear.
Where the fibrinolytic enzyme supports flow, this one supports the cleanup — including a healthy inflammatory balance in the vessel wall and the tissue around it.
Plant-based and vegan. Gluten-free, soy-free, dairy-free, non-GMO. No fillers. Third-party tested.
The Mechanism
Your Body Already Owns a Clot-Clearing System. Nattokinase Works on Five of Its Levers.
Fibrinolysis is not exotic biology. It runs in every healthy person, every day. Plasminogen circulates in the blood as an inactive precursor. When it is switched on, it becomes plasmin, and plasmin is the enzyme that dismantles fibrin. The whole system has an accelerator and a brake, and researchers have described nattokinase acting on both.
Plasmin, up. More of the body's own fibrin-dissolving enzyme in circulation.
Pro-urokinase and urokinase, up. The activators that convert plasminogen into plasmin in the first place.
PAI-1, down. Plasminogen activator inhibitor type 1 is the brake on the entire system. Release the brake and the body's own housekeeping speeds back up.
Factor VII and Factor VIII, down. Two inputs to the clotting cascade itself.
Fibrinogen and fibrin, down. Less raw material for the mesh, and less mesh left standing.
This diagram describes mechanism — what has been observed about nattokinase in laboratory, animal, and blood-sample research. Mechanism explains how something could plausibly work. It is not the same as a clinical outcome in people, which is a separate question and the subject of the section below. Read it as the biology, not as a promise.
It is also the reason the cautions on this page are written the way they are. An input with real activity in the clotting system deserves real respect, particularly alongside medication that works on the same pathways.
The Human Data
1,062 People. Twelve Months. And a Dose Question Nobody Was Asking.
In 2022, researchers published the largest clinical dataset on nattokinase to date in Frontiers in Cardiovascular Medicine. They followed 1,062 adults, average age 67, who took nattokinase daily for twelve months, and measured blood lipids and carotid ultrasound before and after.
At 10,800 FU per day, the group showed lower total cholesterol, lower triglycerides, lower LDL cholesterol, higher HDL cholesterol, and measurable reductions in carotid intima-media thickness and carotid plaque area. At 3,600 FU per day, a group of 61 participants showed essentially no change at all. Same enzyme. Same twelve months. Different dose, different result.
The authors' conclusion is the part worth sitting with: they argued the effective range for nattokinase runs somewhere between 6,000 and 12,000 FU per day, and they openly challenged the 2,000 FU figure that most of the supplement industry has been anchored to for years.
What this study is, and what it is not
This was a retrospective analysis of medical records, not a randomized controlled trial. Participants were not blinded and there was no placebo group. Several of the authors were employed by the company that manufactured the nattokinase used. The cohort was Chinese, older, and already hyperlipidemic. A correction to the paper was published later that year. And a separate randomized trial in healthy, low-risk adults using 2,000 FU per day found no effect on subclinical atherosclerosis — which is consistent with the dose finding above, but is still a null result in a stronger study design.
Mechanism, association, and randomized outcome are three different things, and we do not blur them. This research is about nattokinase as a nutrient. It is not a study of FLOW, and nothing here should be read as a claim about what FLOW will do for you. FLOW is a dietary supplement intended to support normal structure and function, not to diagnose, treat, cure, or prevent any disease.
This is why FLOW is dosed the way it is. Not because a bottle looks better with a bigger number on it, but because the literature keeps pointing to the same conclusion: the standard supplemental dose of nattokinase is a rounding error, and the studies that show something happening are the studies that used more.
Who FLOW Is For
FLOW belongs in the plan of people who want to be proactive about circulation rather than reactive about a diagnosis:
People with a family history of heart attack or stroke who want to support cardiovascular wellness upstream
People working on cholesterol, blood pressure already in the normal range, or overall vascular health through a root-cause plan
People who notice heaviness in the legs, cold hands and feet, or sluggish circulation
People who sit for long stretches, fly frequently, or live a life their circulation was not designed for
People already eating well, moving, sleeping, and testing — who want the enzyme layer on top of a real foundation
People who want fewer prescriptions in their future, not more
Who Should Not Take FLOW
This formula is not for everyone, and we would rather tell you plainly than sell you something you should not take. Do not use FLOW, or speak with your physician first, if you:
Take prescription blood thinners or antiplatelet medication. Have a bleeding or clotting disorder. Have a mechanical heart valve. Are pregnant or nursing. Have surgery or a dental procedure scheduled — enzymes of this type are typically stopped in advance, and that decision belongs to the physician performing it.
If you are on any medication that affects clotting, this is a conversation to have with your doctor before your first capsule, not after.
"I formulated FLOW to put a missing ancestral input back on the table. Fermented foods gave our great-grandparents fibrinolytic enzymes every day. Almost nobody eats that way now. This is how I close that gap with my patients around the world."
Dr. Jack Wolfson, DO — Cardiologist since 2002
How to Take FLOW
Standard serving
One capsule twice daily on an empty stomach — 9,032 FU per day. Keep the bottle on your nightstand. One capsule first thing in the morning before food, one right before bed. Enzymes taken with a meal go to work on the meal instead of the bloodstream, so the empty stomach is not optional.
Advanced serving
One capsule three times daily away from food — 13,548 FU per day. This is a step-up we reserve for patients working directly with our clinical team, because bleeding risk, medications, and upcoming procedures all have to be accounted for first. Do not start here on your own.
Test, Don't Guess
FLOW is a tool, not a plan. Enzymes do not fix a diet built on industrial seed oils, a bedroom full of light at night, a mouth full of infection, or a body that never sees the sun. They are one input among many, and they work best on top of a foundation that is already in place.
The way to know where you actually stand is to measure it. Oxidative stress, advanced lipid markers, inflammatory markers, and imaging tell you what your body is doing right now — and they tell you whether what you are doing is working. Order testing, get the results reviewed by our clinical team, and build the plan from data instead of guesswork.
Questions People Ask
What is FLOW?
A two-enzyme formula from Natural Heart Doctor combining NattoZimes®, a nattokinase-type fibrinolytic enzyme, with Serrazimes®, a serrapeptase-equivalent proteolytic enzyme. Together they support healthy circulation, normal fibrinolytic activity, and a healthy inflammatory balance in the vascular system.
How does FLOW work?
Your body has its own system for clearing fibrin — the protein mesh that gives a clot its structure. Nattokinase-type enzymes support that normal fibrinolytic activity, which is how the body maintains smooth blood flow on its own. Serrapeptase-type enzymes are proteolytic, meaning they act on proteins and cellular debris, supporting the body's normal cleanup processes and a healthy inflammatory balance. Neither one replaces a prescribed medication, and neither should be used as a substitute for one.
Why is FLOW dosed higher than most nattokinase supplements?
Because the research keeps pointing that direction. Human studies using roughly 2,000 FU per day have largely come back flat, while studies using 6,000 FU and above have shown measurable changes in the markers researchers were tracking. FLOW delivers 4,516 FU per capsule, or 9,032 FU per day at the standard serving. Dose matters with enzymes the same way it matters with everything else.
Can I take FLOW with a blood thinner?
Not without your physician's involvement. Nattokinase-type enzymes support normal fibrinolytic activity, and combining that with anticoagulant or antiplatelet medication is a clinical decision, not a shopping decision. The same applies to bleeding disorders, mechanical heart valves, and any scheduled surgery or dental procedure. FLOW is never a replacement for a prescribed anticoagulant.
How long before I notice anything?
Some people notice changes in how their legs and hands feel within a few weeks. Many notice nothing they can point to, which is normal — this is a long-game formula supporting a system that works quietly when it works well. Consistency over months is what matters. If you want to know whether it is doing something, test.
Are there side effects?
FLOW is generally well tolerated. Mild digestive discomfort can occur when starting. Because these enzymes support fibrinolytic activity, watch for easy bruising or prolonged bleeding from a minor cut and speak with your physician if you notice either.
Is FLOW vegan, gluten-free, and non-GMO?
Yes to all three. Both enzymes are produced by fermentation from vegetarian fungal sources rather than extracted from soy, and the capsule is plant-based. Free of gluten, dairy, soy, and animal-derived ingredients. Every batch is third-party tested for purity and potency.
Who formulated it?
Dr. Jack Wolfson, DO, a cardiologist since 2002 and the founder of Natural Heart Doctor. His team of physicians, nutritionists, and coaches sees patients by telemedicine worldwide and in person in Scottsdale, Arizona.
What if it is not right for me?
Ninety-day satisfaction guarantee. If you are not happy, contact our team for a refund or exchange. Subscribe and Save keeps you from running out and lowers the cost. We ship worldwide, typically within 24 hours.
Patient Reviews
In Their Own Words
Real Results with FLOW
Hear it from the people taking it.
★★★★★
"I have been taking Flow since 2022. It has worked great!"
David A. Coe
★★★★★
"I've been taking flow for more than a year. I feel good and helps support my blood flow."
Paula Brown
★★★★★
"Definitely works to thin my blood and break up potential clots!"
Ron C.
Every review of FLOW appears below. These reflect the individual experiences of the people who wrote them. Results are not typical and will vary. Customer statements have not been evaluated by the Food and Drug Administration and are not intended to diagnose, treat, cure, or prevent any disease.
Blood Is Meant to Move
Give the body what it needs. Take away what it does not. FLOW is one input on the list — and it is the one most people are missing entirely.
Order FLOW Today — $69.43
Free shipping over $99 | 90-day satisfaction guarantee | Subscribe and Save available
Cheers to Your 100 Year Heart
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. Consult your physician before beginning any supplement, particularly if you take medication, have a medical condition, are pregnant or nursing, or have a procedure scheduled. Seek urgent medical evaluation for new or worsening chest pain, fainting, severe shortness of breath, or neurologic symptoms.
Frequently Asked Questions
About Flow
Q: What is Flow?
A: Flow is a targeted supplement from Natural Heart Doctor that combines two powerful enzymes—nattokinase and serrapeptase—to support healthy circulation, flexible blood vessels, and strong cardiovascular health.
Q: How does Flow work?
A: Flow helps your body naturally maintain smooth, healthy blood flow.
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Nattokinase supports normal clotting, helps break down arterial plaque, and promotes healthy carotid arteries.
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Serrapeptase reduces excess fibrin and inflammatory proteins, supporting vessel flexibility and resilience.
Together, they help protect against arterial damage, poor circulation, and the risks of heart attack and stroke.
Q: Who should consider taking Flow?
A: Flow may be especially helpful for people with:
- Family history of heart disease or stroke
- High blood pressure or cholesterol
- Circulation issues (heavy legs, swelling, cold extremities)
- Stiffness in arteries or early signs of vascular damage
Always consult your doctor before beginning any supplement program, especially if you are pregnant, nursing, or taking medication.
Q: How do I take Flow?
A: Take 1 capsule twice daily, away from food. We recommend keeping it on your nightstand: take one capsule first thing in the morning and one right before bed.
Q: When will I notice results?
A: Many people report feeling improvements in circulation, energy, and overall wellness within weeks. However, Flow works best as part of a long-term cardiovascular support plan. Consistency is key.
Q: Are there any side effects?
A: Flow is generally well-tolerated. Some individuals may experience mild digestive discomfort when starting. Because nattokinase supports normal clotting, consult your physician before use if you are taking blood-thinning medication or have a bleeding disorder.
About Ingredients & Quality
Q: Where are Flow's ingredients sourced?
A: We source nattokinase and serrapeptase from trusted suppliers, ensuring purity and potency. Every batch is third-party tested for quality, safety, and effectiveness.
Q: Is Flow vegan and gluten-free?
A: Yes, Flow is free from gluten, dairy, soy, and animal-derived ingredients.
Q: Is Flow non-GMO?
A: Absolutely. Natural Heart Doctor supplements are crafted with non-GMO ingredients.
About Natural Heart Doctor (NHD)
Q: Who is behind Flow?
A: Flow was formulated by Dr. Jack Wolfson, a cardiologist who has dedicated his career to helping people achieve a "100 Year Heart" through natural, evidence-based strategies. Natural Heart Doctor (NHD) offers supplements, medical services, in-home tests, and educational resources to support total heart health.
Q: Does Dr. Wolfson take patients?
A: Yes. Dr. Wolfson and his team of naturopathic physicians, nutritionists, and coaches see patients virtually and at the Natural Heart Doctor clinic in Scottsdale, Arizona.
Ordering & Policies
Q: Where can I buy Flow?
A: Flow is only available through Natural Heart Doctor's online store and clinic. This ensures product authenticity and the highest quality control.
Q: Do you offer Subscribe & Save?
A: Yes. With Subscribe & Save, you'll never run out of Flow—you'll get automatic deliveries at the frequency you choose, plus exclusive discounts.
Q: What is your return policy?
A: We offer a 90-day satisfaction guarantee. If you're not completely happy with your purchase, contact our support team for a refund or exchange.
Q: Do you ship internationally?
A: Yes, we ship worldwide. Shipping costs and delivery times vary by location. All orders are shipped promptly, typically within 24 hours.
Q: How can I contact Natural Heart Doctor?
A: Our customer support team is here to help. You can reach us at orders@naturalheartdoctor.com.
