Nattokinase: What the Research Actually Says About This Japanese Enzyme

Nattokinase is an enzyme extracted from natto, a traditional Japanese food made from fermented soybeans. It has been a staple of Japanese cuisine for over a thousand years, and researchers have been studying it seriously since the 1980s when Japanese scientist Dr Hiroyuki Sumi first isolated the enzyme and observed its effects on blood clots in laboratory conditions.

It belongs to a class of enzymes called serine proteases, and its primary action is fibrinolytic - meaning it breaks down fibrin, the protein that forms the structural scaffolding of blood clots. That single mechanism is why nattokinase has attracted serious attention in cardiovascular research over the past two decades.

Interest has accelerated recently, driven in part by broader public awareness of cardiovascular risk factors and a growing audience looking at nutrition and supplementation as part of a long-term heart health strategy. Nattokinase is not a drug, and it is not a treatment for any condition. But the research behind it is more substantial than most supplements in this space.

What the research actually shows

The cardiovascular research on nattokinase focuses on three main areas: blood pressure, blood viscosity, and fibrinolytic activity.

Blood pressure. A randomised controlled trial published in Hypertension Research (2008) followed 86 participants over eight weeks. Those taking nattokinase saw statistically significant reductions in both systolic and diastolic blood pressure compared to placebo. The effect was modest but consistent. View study

Fibrinolytic activity. A study published in Scientific Reports (2015) measured nattokinase's ability to dissolve fibrin directly, comparing it to plasmin (the body's own clot-dissolving enzyme). Nattokinase demonstrated strong fibrinolytic activity, with researchers noting it could degrade multiple fibrin-related proteins that plasmin cannot. View study

Blood viscosity and flow. Research published in the Journal of Cardiovascular Pharmacology (2009) examined the effects of nattokinase supplementation on markers of blood viscosity and clotting factors in healthy volunteers. Results indicated meaningful reductions in plasma viscosity and fibrinogen levels over the study period. View study

The overall picture is of an enzyme that works on multiple points in the coagulation and fibrinolysis pathway - not dramatically, not as a replacement for medical intervention, but consistently and measurably.

What nattokinase does not do

This section matters. A lot of supplement marketing in this space overclaims, and it does the category a disservice.

Nattokinase is not a treatment for cardiovascular disease. It has not been studied as a replacement for anticoagulant medications. If you are on blood thinners, have a clotting disorder, or have been advised by a doctor about cardiovascular risk, you should not add nattokinase to your routine without speaking to your GP first - the combination of nattokinase and anticoagulant medication could amplify blood-thinning effects.

The research base, while promising, is also still relatively limited in scale. Most studies have been small and short-term. Larger, longer trials are needed before any firm clinical conclusions can be drawn.

What the research does support is nattokinase as a nutritional supplement with a plausible and studied mechanism of action for people interested in cardiovascular health as part of a broader diet and lifestyle approach.

Who is nattokinase most relevant for?

The people most likely to benefit from nattokinase supplementation, based on the research profile, are those who:

• Have a family history of cardiovascular issues and are taking a proactive approach to heart health
• Are in their 40s or older and focused on longevity and healthy ageing
• Are already following a clean diet and exercise routine and want to add targeted nutritional support
• Have read or heard about nattokinase through longevity-focused podcasts or research and want a reliable, quality source

It fits naturally into the same category as omega-3s and CoQ10 - not a magic fix, but a well-researched tool with a sensible place in a long-term health strategy.

What to look for in a nattokinase supplement

Not all nattokinase supplements are equal. A few things worth checking before you buy:

Source and purity. The enzyme should be derived from fermented soy (natto) and ideally certified organic. Non-organic sources may carry pesticide residues from the soy fermentation process.

Dosage. Research studies have typically used doses in the range of 2,000 FU (fibrinolytic units) per day. Check that the product you choose uses FU measurement rather than just milligrams, as milligrams alone do not tell you how enzymatically active the product is.

Added ingredients. Some formulations include prebiotic fibre such as inulin, which supports gut health and may improve the environment for the enzyme's absorption. This is a useful addition rather than a gimmick.

The Feel Supreme Organic Nattokinase with Inulin (60 capsules, available exclusively at Powerful.ie in Ireland) ticks all of these boxes - certified organic, sourced from fermented soy, paired with inulin for digestive support. At 4,000 FU per capsule, it delivers double the dosage used in most published studies, in a 60-day supply at one capsule per day.

Shop Feel Supreme Organic Nattokinase with Inulin - €34.95

As a food supplement for adults. Not a substitute for a varied, balanced diet and healthy lifestyle. If you are pregnant, breastfeeding, under medical supervision, or taking anticoagulant medication, consult a healthcare practitioner before use.