Lumbrokinase is one of those supplements that sounds strange until you learn about its history. It’s an enzyme extracted from earthworms, and yes, people actually take it. The supplement has gained attention in cardiovascular health circles because it supposedly breaks down blood clots without the bleeding risks associated with standard clot-busting drugs.

I’ve gone through the clinical research on lumbrokinase, and here’s my honest assessment: the evidence is thin. There are a handful of studies, most from China, with small sample sizes and methodological limitations. That doesn’t mean the supplement is worthless, but anyone considering it should understand what the research actually shows rather than relying on marketing claims.

What is lumbrokinase?

Lumbrokinase is a group of fibrinolytic enzymes extracted from earthworms, specifically Lumbricus rubellus. In traditional Chinese medicine, dried earthworm preparations (called “di long” or “earth dragon”) have been used for centuries to treat various conditions including fever, seizures, and circulation problems [1].

The modern interest in lumbrokinase started in the 1980s when Japanese researchers isolated the enzyme and found it could break down fibrin, the protein that forms the structural framework of blood clots. Unlike pharmaceutical clot-busters like streptokinase or tissue plasminogen activator (tPA), lumbrokinase appears to work through multiple mechanisms:

It directly dissolves fibrin (the main component of clots)
It activates plasminogen, the body’s own clot-dissolving system
It may have some anti-platelet effects

The appeal of lumbrokinase over pharmaceutical thrombolytics is the claim that it’s more selective for fibrin and less likely to cause uncontrolled bleeding. Whether this actually translates to better safety in humans remains unclear.

How lumbrokinase is measured and dosed

Lumbrokinase activity is measured in units, but there’s no standardised measurement system, which creates confusion. Different manufacturers use different assays, so comparing products is difficult.

Studies have typically used doses ranging from 300,000 to 600,000 units per day, usually divided into two or three doses. However, without standardised testing methods, it’s hard to know whether a “600,000 unit” product from one manufacturer delivers the same activity as a “600,000 unit” product from another.

This lack of standardisation is a genuine problem for anyone trying to evaluate lumbrokinase products.

What does the research show?

I should be clear from the start: the evidence base for lumbrokinase is limited. Most studies come from China, many have small sample sizes, and some lack proper controls. That said, here’s what the existing research suggests.

1. Secondary prevention of ischaemic stroke

Stroke is the fourth leading cause of death in many Western countries. About 85% of strokes are ischaemic, meaning they’re caused by blocked blood vessels rather than bleeding [2]. Once someone has had a stroke, preventing another one becomes a priority.

One randomised controlled trial followed 310 patients who had previously experienced an ischaemic stroke [3]. Half received lumbrokinase capsules (600,000 units three times daily) alongside standard care, while the other half received placebo. The study ran for 12 months.

The lumbrokinase group showed improvements in several measures: lower fibrinogen levels, reduced carotid plaque volume, better scores on stroke severity scales, and fewer subsequent cardiovascular events.

My honest take: this is the strongest study on lumbrokinase I’ve found, but one trial isn’t definitive. The results are encouraging enough to warrant further research, but I wouldn’t call the evidence conclusive. For anyone who has experienced an ischaemic stroke, the standard treatments like aspirin and statins have far more evidence behind them.

2. Pulmonary embolism treatment

Pulmonary embolism occurs when a blood clot blocks arteries in the lungs. It’s potentially fatal and typically requires immediate treatment with anticoagulants and sometimes clot-dissolving drugs.

A small trial enrolled 60 patients with acute pulmonary embolism classified as “moderate risk” [4]. The treatment group received lumbrokinase in addition to standard therapy (low molecular weight heparin plus warfarin), while the control group received only the standard medications.

After 30 days, patients receiving lumbrokinase showed greater improvements in heart function markers and pulmonary artery pressure compared to controls.

Here’s the catch: this was a small study (60 patients), short duration (30 days), and lumbrokinase was added on top of conventional treatment rather than compared against it. Nobody’s suggesting lumbrokinase should replace standard pulmonary embolism treatment. At best, it might offer some additional benefit, but more research is needed.

3. Stable angina improvement

Angina is chest pain caused by reduced blood flow to the heart muscle, usually due to narrowed coronary arteries from atherosclerosis. “Stable” angina means the symptoms follow a predictable pattern, typically triggered by exertion.

One open-label study treated 10 patients with stable angina using lumbrokinase (300,000 units daily) for 30 days [5]. Myocardial perfusion imaging showed improvements in blood flow to the heart muscle.

I’m going to be blunt about this one: ten patients, no control group, 30 days. This is preliminary data at best. It might suggest lumbrokinase warrants further study for angina, but you can’t draw meaningful conclusions from such a small, uncontrolled trial. Anyone with angina should follow their doctor’s recommendations regarding proven treatments.

What the evidence doesn’t support

Based on my review of the literature, several common marketing claims lack adequate support:

Preventing heart attacks in healthy people: No studies have examined whether lumbrokinase prevents cardiovascular events in people without existing disease.

Treating deep vein thrombosis: While the mechanism suggests potential benefit, I couldn’t find controlled trials specifically studying DVT treatment.

Improving general circulation: Vague claims about “blood flow” don’t have specific research backing.

Side effects

The limited human research on lumbrokinase hasn’t identified serious side effects, but the studies are small and short-term. Reported side effects include:

Nausea
Bloating
Diarrhoea
Skin rash
Allergic reactions

The more concerning issue is the theoretical bleeding risk. Lumbrokinase breaks down fibrin and reduces platelet aggregation. While proponents argue it’s safer than pharmaceutical thrombolytics, anyone who takes a clot-dissolving supplement is potentially at increased bleeding risk.

There simply isn’t enough long-term safety data to know what happens with extended use.

Safety precautions (2 contraindications)

Who should avoid lumbrokinase

Pregnant or breastfeeding women: There’s no safety data in pregnancy or lactation. Given the lack of evidence, it’s not worth the risk.

Children: No studies have examined use in children.

Drug interactions and medical conditions

People taking blood thinners: This is the big one. Lumbrokinase combined with anticoagulants (warfarin, heparin) or antiplatelet drugs (aspirin, clopidogrel) could potentially cause serious bleeding. The combination hasn’t been studied for safety, and I wouldn’t risk it.

People with bleeding disorders: Anyone with haemophilia or other clotting disorders should avoid lumbrokinase.

Before surgery: Because lumbrokinase may affect clotting, it should be stopped at least two weeks before any surgical procedure. Inform your surgeon and anaesthetist about any supplements you take.

How lumbrokinase compares to similar supplements

Lumbrokinase often gets compared to nattokinase, another fibrinolytic enzyme supplement derived from fermented soybeans. Both claim to support cardiovascular health by breaking down fibrin.

The research base for nattokinase is somewhat larger, though still limited by Western standards. Some studies suggest nattokinase may have modest effects on blood pressure and clotting factors. Whether one is “better” than the other is impossible to say given the current evidence.

Other supplements marketed for cardiovascular health, like fish oil and CoQ10, have considerably more research behind them.

The bottom line

Lumbrokinase has an interesting mechanism and a long history of traditional use. The handful of clinical studies suggest it might have some benefit for people with existing cardiovascular disease, particularly as an add-on to standard treatment.

However, the evidence is thin. Most studies are small, many lack proper controls, and long-term safety data doesn’t exist. Anyone considering lumbrokinase should:

Not use it as a substitute for proven cardiovascular treatments
Tell their doctor before starting it, especially if taking blood thinners
Stop it before surgery
Understand that the marketing claims often exceed what the research supports

For people with conditions like diabetic kidney disease or those at risk of blood clots, the decision about supplements should be made in consultation with a healthcare provider who can weigh the risks and benefits based on individual circumstances.

References

Wang YH, et al. Pharmacological activities and clinical applications of earthworm extracts. Pharm Biol. 2012;50(6):789-796. PMID: 22385076
Virani SS, et al. Heart Disease and Stroke Statistics-2020 Update. Circulation. 2020;141(9):e139-e596. PMID: 31992061
Cao H, et al. Oral lumbrokinase for secondary prevention of ischemic stroke: a randomised, double-blind, placebo-controlled clinical trial. Eur J Neurol. 2013;20(12):1570-1575. PMID: 24229674
Zhang L, et al. Efficacy and safety of lumbrokinase in the treatment of acute moderate-risk pulmonary embolism. J Thromb Thrombolysis. 2018;45(1):138-142. PMID: 29093246
Jin L, et al. Improvement of myocardial perfusion in patients with stable angina after treatment with lumbrokinase. J Int Med Res. 2009;37(6):1830-1835. PMID: 19416019
NHS. Blood-thinning medicines. Available at: https://www.nhs.uk/conditions/anticoagulants/
Mayo Clinic. Blood thinners: Side effects and how to manage them. Available at: https://www.mayoclinic.org/diseases-conditions/deep-vein-thrombosis/in-depth/warfarin-side-effects/art-20047592