Natto and its active ingredient nattokinase: a potent and safe thrombolytic agent

This is the article that helped launch nattokinase’s reputation in the West — and reading it now is a lesson in how a claim can outrun its evidence for two decades.

Published in an alternative-medicine journal, it presents nattokinase, the enzyme from fermented soy, as a potent, safe, natural clot-dissolver, compiling in vitro, animal, and anecdotal human reports of effects on clot breakdown, blood viscosity, and blood pressure. The framing is frankly advocational: a low-cost oral supplement positioned against pharmaceutical thrombolytics.

The status-quo angle is the whole point of the piece — challenging pharmaceutical dominance with a cheap supplement — but that advocacy is also its weakness.

Our rating is the lowest in this library, deliberately. We score the evidence at the bottom: a non-peer-reviewed narrative review with no original data, strong claims, a promotional tone, and authors with clinical and commercial stakes. Clinical significance gets a middling score only on the conditional — a safe oral thrombolytic would matter if any of this were rigorously proven. It hasn’t been. Read this as the origin of the nattokinase hype, not as evidence for it; the rigorous meta-analysis in this same library (Li et al., 2023) is where to look for what’s actually established.