N-acetylcysteine (NAC) has a long history of use to help prevent liver damage, and more recently as a treatment for flu viruses. Now researchers have discovered its lifesaving value for COVID-19. N-acetylcysteine (NAC) is a precursor to reduced glutathione, which appears to play a crucial role in COVID-19. According to an April 2020 literature analysis, glutathione deficiency may be associated with COVID-19 severity, leading the author to conclude that NAC may be useful both for its prevention and treatment. NAC has a long history of use as a first-aid remedy for acetaminophen poisoning. It neutralizes the toxic effects of the drug by recharging glutathione, thereby preventing liver damage. But the idea that NAC can also be helpful against viral infections is not new. Previous studies have found it reduces viral replication of certain viruses, including the influenza virus. In one such study, the number needed to treat (NNT) was 0.5, which means for …