Abstract: TYPE Original Research PUBLISHED 13 January 2023 DOI 10.3389/fphar.2022.1096853 OPEN ACCESS EDITED BY Michał Tomczyk, Medical University of Bialystok, Poland REVIEWED BY Mithun Rudrapal, Rasiklal M. Dhariwal Institute of Pharmaceutical Education and Research, India Maria Russo, Institute of Food Sciences, National Research Council (CNR), Italy Syed Mohammed Basheeruddin Asdaq, University of Almaarefa, Saudi Arabia *CORRESPONDENCE Francesco Di Pierro, f.dipierro@vellejaresearch.com Amjad Khan, amjadkhan@lumhs.edu.pk SPECIALTY SECTION This article was submitted to Ethnopharmacology, a section of the journal Frontiers in Pharmacology RECEIVED 12 November 2022 Quercetin as a possible complementary agent for early-stage COVID-19: Concluding results of a randomized clinical trial Francesco Di Pierro 1,2*, Amjad Khan 3*, Somia Iqtadar 4, Sami Ullah Mumtaz 4, Muhammad Nabeel Akbar Chaudhry 5, Alexander Bertuccioli 6, Giuseppe Derosa 7,8, Pamela Maffioli 8, Stefano Togni 9, Antonella Riva 9, Pietro Allegrini 9, Martino Recchia 10 and Nicola Zerbinati 11 1 Scientific and Research Department, Velleja Research, Milan, Italy, 2Digestive Endoscopy, Fondazione Poliambulanza, Brescia, Italy, 3INEOS Oxford Institute for Antimicrobial Research, University of Oxford, Oxford, United Kingdom, 4Department of Medicine, King Edward Medical University, Lahore, Pakistan, 5 Punjab Institute of Cardiology, Lahore, Pakistan, 6Department of Biomolecular Sciences, University of Urbino, Urbino, Italy, 7Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy, 8Centre of Diabetes and Metabolic Diseases, Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy, 9R&D Department, Indena S.p.A, Milan, Italy, 10Medistat, Milan, Italy, 11 Department of Medicine and Surgery, University of Insubria, Varese, Italy ACCEPTED 15 December 2022 PUBLISHED 13 January 2023 CITATION Di Pierro F, Khan A, Iqtadar S, Mumtaz SU, Chaudhry MNA, Bertuccioli A, Derosa G, Maffioli P, Togni S, Riva A, Allegrini P, Recchia M and Zerbinati N (2023), Quercetin as a possible complementary agent for early-stage COVID-19: Concluding results of a randomized clinical trial. Front. Pharmacol. 13:1096853. doi: 10.3389/fphar.2022.1096853 COPYRIGHT © 2023 Di Pierro, Khan, Iqtadar, Mumtaz, Chaudhry, Bertuccioli, Derosa, Maffioli, Togni, Riva, Allegrini, Recchia and Zerbinati. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Frontiers in Pharmacology Background: Quercetin, a natural polyphenol with demonstrated broadspectrum antiviral, anti-inflammatory, and antioxidant properties, has been proposed as an adjuvant for early-stage coronavirus disease 2019 (COVID19) infection. Objective: To explore the possible therapeutic effect of quercetin in outpatients with early-stage mild to moderate symptoms of COVID-19. Methods: This was an open-label randomized controlled clinical trial conducted at the department of medicine, King Edward Medical University, Lahore, PK. Patients were randomized to receive either standard of care (SC) plus an oral quercetin supplement..