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At a Glance
- Varicose veins We found no clinical trials of nattokinase for varicose veins.
- Circulation Small studies show effects on clotting tests3 and faster rewarming of the hands after cold water4, but not better circulation in daily life.
- Long flights One trial found fewer clots in high-risk travelers taking Flite Tabs, a combination product, not nattokinase alone5.
- What helps varicose veins Compression stockings, walking, raising your legs and avoiding long periods of standing or sitting7.
- Top pick Nutricost Nattokinase 2,000 FU – the #1 pick in our guide to the best nattokinase supplements: one capsule a day at the 2,000 FU dose used in most trials.
The Short Answer: There’s no good evidence that nattokinase helps varicose veins. It does affect clotting3, and small studies suggest effects on blood flow markers4, but no trial has tested whether it shrinks varicose veins or relieves their symptoms. The main proven self-care steps are compression stockings, regular walking and raising your legs7.
On this page
If you have varicose veins with pain, swelling, skin changes or a hard, tender lump, see a doctor, since a clot needs proper treatment. For an overview of what nattokinase can do, see our guide to nattokinase benefits, or compare products in our guide to the best nattokinase supplements.
Nattokinase and Circulation: What Studies Show
| Claim | What human studies show | Evidence |
|---|---|---|
| Improves circulation | Faster hand rewarming after cold water in 9 men4 | Very small study |
| Prevents clots on long flights | Fewer clots with Flite Tabs, a combination product5 | One trial, not nattokinase alone |
| Breaks down clots | Changes in clotting tests3 | Lab markers only |
| Helps varicose veins | No trials found | Not studied |
| Relieves vein symptoms | Improvement in hospital patients without a control group6 | Observational |
| Improves artery health | No effect over 3 years2 | Not supported |
Varicose Veins
Varicose veins are swollen, twisted veins, usually in the legs. Marketing often links nattokinase to them because it breaks down fibrin, a clotting protein1. But we found no trial showing that nattokinase changes varicose veins or their symptoms.
The closest data come from a vascular surgery unit, where 153 patients with deep or superficial vein clots or venous insufficiency were given nattokinase, some alongside injected blood thinners. Symptoms improved, but without a control group the study can’t show that nattokinase caused the improvement6.
Our Top Nattokinase Pick
Nutricost Nattokinase 2,000 FU
2,000 FU1 capsule a day120 servings
Nattokinase isn’t a varicose vein treatment, but if you want to try it for general heart health and your doctor agrees, Nutricost gives the 2,000 FU dose used in most trials in one capsule. It’s the #1 pick in our guide to the best nattokinase supplements. It isn’t suitable if you take aspirin or a blood thinner, or have had a DVT.
Blood Flow and Clots
Nattokinase lengthened clotting tests compared with placebo over 8 weeks3, and one dose helped hands rewarm faster after cold water in a tiny study4. In a trial of 204 high-risk travelers on 7–8 hour flights, none taking Flite Tabs developed a clot, compared with 5.4% on placebo, but the product was a combination5.
These results don’t mean nattokinase can treat or prevent a deep vein thrombosis (DVT). If you’ve had a DVT, MSK advises against nattokinase because of a theoretical risk of dislodging a clot1. See our guide to nattokinase side effects.
What Actually Helps Varicose Veins
MedlinePlus recommends these self-care steps7:
- Wear compression stockings as advised by your provider.
- Stay active: walking or swimming for about 30 minutes, about 5 times a week.
- Raise your legs above your heart for 5–15 minutes, 3 or 4 times a day.
- Avoid long periods of sitting or standing, and bend and straighten your legs every few minutes when you can’t move around.
- Look after your skin and get any sores checked quickly.
See your doctor if your veins become more painful, you get a fever or redness in your leg, pain or swelling suddenly gets worse, a sore develops, a vein bleeds, or you feel a hard lump in a vein, which could be a clot7.
If you’re comparing supplements for vein health, see our guides to the best vein support supplements and best butcher’s broom supplements.
Final Verdict
Nattokinase hasn’t been tested for varicose veins, and the evidence for better circulation is limited to clotting tests, a tiny rewarming study and one trial of a combination product. It’s not a treatment for varicose veins or clots, and it’s risky for people on blood thinners or with a history of DVT.
If you want to try nattokinase for general heart health and your doctor agrees, use the studied 2,000 FU dose, such as Nutricost Nattokinase 2,000 FU. Compare all 7 picks in our guide to the best nattokinase supplements, and check our guide to nattokinase and blood thinners first.
Important: This guide is for general information and isn’t medical advice. Get urgent care for sudden leg swelling, pain or redness, which can be signs of a clot. Don’t take nattokinase with blood thinners or aspirin without your doctor’s approval.
Frequently Asked Questions
Does nattokinase help varicose veins?
There’s no clinical evidence that it does. We didn’t find any trials of nattokinase for varicose veins.
Does nattokinase improve circulation?
Can nattokinase prevent blood clots on flights?
One trial found fewer clots in high-risk travelers taking Flite Tabs5, but the product was a combination, and nattokinase alone hasn’t been tested this way.
Can nattokinase dissolve a DVT?
No. A suspected DVT needs medical treatment, and MSK advises people with a history of DVT not to use nattokinase1.
What’s the best way to treat varicose veins at home?
Compression stockings, regular walking, raising your legs and avoiding long periods of standing or sitting7.
Sources & History
References
- Nattokinase — Memorial Sloan Kettering Cancer Center, About Herbs, 2025
- Nattokinase Atherothrombotic Prevention Study: A Randomized Controlled Trial — Clinical Hemorheology and Microcirculation, 2021
- The Effects of Nattokinase Supplementation on Collagen-Epinephrine Closure Time, Prothrombin Time and Activated Partial Thromboplastin Time in Nondiabetic and Hypercholesterolemic Subjects — Food & Function, 2019
- A Single Dose of Oral Nattokinase Accelerates Skin Temperature Recovery After Cold Water Immersion: A Double-Blind, Placebo-Controlled Crossover Study — Heliyon, 2023
- Prevention of Venous Thrombosis in Long-Haul Flights With Flite Tabs: The LONFLIT-FLITE Randomized, Controlled Trial — Angiology, 2003
- Data Recorded in Real Life Support the Safety of Nattokinase in Patients With Vascular Diseases — Nutrients, 2021
- Varicose and Other Vein Problems – Self-Care — MedlinePlus, National Library of Medicine, 2024
Update history
- Rewritten to state clearly that nattokinase hasn’t been tested for varicose veins, with a table of circulation evidence, the Flite Tabs flight trial, a hospital study, and MedlinePlus self-care advice.
