Relationship of quercetin intake and oxidative stress in persistent Covid

Matías-Pérez et al., Frontiers in Nutrition, doi:10.3389/fnut.2023.1278039, Dec 2023

Quercetin for COVID-19

36th treatment shown to reduce risk in January 2022, now with p = 0.0018 from 9 studies.

No treatment is 100% effective.
Protocols combine treatments.

Discussion of the potential of quercetin for persistent COVID-19 symptoms resulting from oxidative stress. Authors explain how COVID-19 leads to oxidative stress through inflammation, cytokine storms, and coagulation abnormalities. Quercetin is a naturally occurring flavonoid antioxidant that can neutralize free radicals, inhibit viral enzymes, reduce platelet aggregation, and have immunoprotective effects. Studies show quercetin inhibits replication of various viruses. Authors suggest a mixture of quercetin and vitamin C could disrupt SARS-CoV-2 entry, replication, and assembly while strengthening the immune response. Authors note the challenges of quercetin's bioavailability indicating that formulations for improved bioavailability are important.
Reviews covering quercetin for COVID-19 include1-22.
Matías-Pérez et al., 26 Dec 2023, peer-reviewed, 5 authors.