NAC’s Effect on Viruses

Nan Fornal
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What is NAC?

Since the 1960s, the antioxidant n-acetylcysteine (NAC), which is found abundantly in onions--and to a lesser extent in other members of the allium family--has known popularity as an antidote to certain poisons and as a mucus-thinning substance. The World Health Organization even includes it in a list of essential medicines.

As with any supplement you are considering, check with your healthcare provider first. Don't take more than the recommended dosage.

Why is NAC Becoming More Popular?

With the rapid spread of COVID-19, which has both a longer incubation period and a higher mortality rate than influenza, many wonder whether particular nutrients can help protect them and their loved ones.

One supplement that is being mentioned is NAC.

Is NAC Effective Against Coronavirus?

  • Not Tested Against COVID-19

    There is as yet no research on NAC's effect on the virus that causes COVID-19. One flu study showed "significantly fewer influenza-like episodes and days of bed confinement" for a group that had taken 600 milligrams (mg) of NAC twice a day for six months, as opposed to a placebo group.

  • Shown to Reduce Apparent A/H1N1

    Authors of research on NAC's effectiveness against another viral illness, A/H1N1, concluded that long-term administration of NAC did not prevent infection, but it did reduce the incidence of "clinically apparent disease."

Click to See Our Sources

"Attenuation of influenza-like symptomatology and improvement of cell-mediated immunity with long-term N-acetylcysteine treatment" by S. De Flora et al., European Respiratory Journal, 7/97

"Coronavirus disease 2019 (COVID-19),", updated 3/19/20

"Medical and dietary uses of N-acetylcysteine" by S. Salamon et al., Antioxidants, 5/19

"Nutraceuticals have potential for boosting the type 1 interferon response to RNA viruses including influenza and coronavirus" by Mark F. McCarty and James J. DiNicolantonio, Progress in Cardiovascular Diseases,, 2/20