evidence: Unsupported: The nattokinase study cited was performed only in vitro, not in people, so it provides no information about nattokinase’s effect in people with long COVID. The exact cause of long COVID still remains unknown. The assertion that long COVID is due to persistent spike protein and can be treated with nattokinase is unsupported by scientific evidence. On 21 February 2023, cardiologist Peter McCullough, who has become known for spreading COVID-19 misinformation during the pandemic, published a Substack post claiming that nattokinase is the "Holy Grail of COVID-19 vaccine detoxification". As evidence for this claim, McCullough cited a study by Tanikawa et al. published in August 2022, which reported that nattokinase can break down the spike protein[1]. Chiropractor Ben Lynch later posted a screenshot of McCullough’s Substack post on Facebook. In the caption of the post, he claimed that nattokinase "may destroy the spike protein". This claim, combined with Lynch’s allegation that the persistence of spike protein is the cause of long COVID, implied that nattokinase could be used to treat long COVID.