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COVID-19 symptoms can cause substantial disability, yet no therapy can currently reduce their frequency or duration. We conducted a double-blind placebo-controlled trial of hesperidin 1000 mg once-daily for 14 days in 216 symptomatic non-vaccinated COVID-19 subjects. Thirteen symptoms were recorded after 3, 7, 10 and 14 days. The primary endpoint was the proportion of subjects with any of four cardinal (group A) symptoms: fever, cough, shortness of breath or anosmia. At baseline, symptoms in decreasing frequency were: cough (53.2%), weakness (44.9%), headache (42.6%), pain (35.2%), sore throat (28.7%), runny nose (26.9%), chills (22.7%), shortness of breath (22.2%), anosmia (18.5%), fever (16.2%), diarrhea (6.9%), nausea/vomiting (6.5%) and irritability/confusion (3.2%). Group A symptoms in the placebo vs hesperidin group was 88.8% vs 88.5% (day 1) and reduced to 58.5 vs 49.4 % at day 14 (OR 0.69, 95% CI 0.38–1.27, p = 0.23). At day 14, 15 subjects in the placebo group and 28 in the hesperidin group failed to report their symptoms. In an attrition bias analysis imputing ″no symptoms″ to missing values, the hesperidin group shows reduction of 14.5 % of group A symptoms from 50.9% to 36.4% (OR: 0.55, 0.32–0.96, p = 0.03). Anosmia, the most frequent persisting symptom (29.3%), was lowered by 7.3% at 25.3 % in the hesperidin group vs 32.6% in the placebo group (p = 0.29). Mean number of symptoms in placebo and hesperidin was 5.10 ± 2.26 vs 5.48 ± 2.35 (day 1) and 1.40 ± 1.65 vs 1.38 ± 1.76 (day 14) (p = 0.92). In conclusion, most non-vaccinated COVID-19 infected subjects remain symptomatic after 14 days with anosmia being the most frequently persisting symptom. Hesperidin 1g daily may help reduce group A symptoms. Earlier treatment of longer duration and/or higher dosage should be tested.

Competing Interest Statement

Pierre Laurin is the CEO of Ingenew Pharma Inc. Frank Cesari, Lyne Gagnon, Karen Thibaudeau, John Moran and Martin Robitaille are all consultants for Ingenew Pharma Inc. The others authors have no competing interests to declare.

Clinical Trial


Funding Statement

The study was funded by the Montreal Heart Institute ( through dedicated donations by the Ariane Riou and Real Plourde Foundation, the Sandra and Alain Bouchard Foundation (, the Lise and Richard Fortin Foundation, Jacques D′Amours and Ingenew Pharma Inc.( Valeo Pharma Inc. ( also supported the study by providing the study drug and placebo free of charge. Ingenew Pharma Inc. played a role in the study design, decision to publish and preparation of the manuscript. The other funders did not play any role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Author Declarations

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.


The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study was reviewed and approved by the Montreal Heart Institute Research and Ethics Committees (2021-2841). All randomized subjects signed an electronic informed consent form using the DocuSign online service.

All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.


I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).


I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.


Paper in collection COVID-19 SARS-CoV-2 preprints from medRxiv and bioRxiv

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