Serum Pharmacokinetics of Nattokinase in Humans Following a Single Oral Daily Dose

A basic question hangs over every oral enzyme supplement: does it actually get absorbed into the bloodstream, or is it simply digested? This small pilot study tried to answer that for nattokinase.

In 11 subjects, the investigators reported detecting nattokinase in serum after ingestion, with levels peaking around 13 hours and significant increases between 2 and 24 hours. They framed it as the first direct evidence that the enzyme is absorbed intact and measurable in human blood.

This is a tiny, preliminary pharmacokinetic study. With only 11 participants and methodological questions about detecting an ingested enzyme intact, its findings are tentative and need independent confirmation. It speaks to absorption, not to any clinical benefit.

We rate the evidence limited. It is a small first step in characterizing nattokinase, of interest mainly for the supplement’s basic pharmacology rather than for any conclusion about cardiovascular health.