Check out this answer from Consensus:
The current evidence suggests that zinc lozenges may be beneficial in reducing the severity and duration of COVID-19 symptoms, particularly in populations at risk of zinc deficiency. However, more extensive and well-designed clinical trials are needed to confirm these findings and establish standardized dosing regimens. Given the potential benefits and relatively low cost, zinc supplementation could be considered as part of a broader strategy to manage COVID-19, especially in high-risk populations.
The COVID-19 pandemic has prompted extensive research into potential treatments and preventive measures. Among these, zinc lozenges have garnered attention due to their known antiviral properties and previous efficacy in treating common cold symptoms. This article explores the effectiveness of zinc lozenges in the treatment and prevention of COVID-19, drawing on findings from multiple research studies.
Mechanism of Action
Zinc is known to possess a variety of antiviral properties. It can enhance both innate and humoral immunity, restore depleted immune cell function, and improve normal immune cell function, particularly in immunocompromised or elderly patients. Zinc may also inhibit viral replication by altering the proteolytic processing of replicase polyproteins and RNA-dependent RNA polymerase (RdRp) in various viruses, including SARS-CoV-210.
Clinical Evidence
Randomized Controlled Trials
A randomized double-blind controlled trial investigated the efficacy of twice-daily oral zinc in COVID-19 patients. The study found that zinc supplementation significantly reduced the combined outcome of death and ICU admission within 30 days, shortened the length of hospital stay, and decreased the duration of COVID-19 symptoms in outpatients1.
Case Reports
A report on four COVID-19 patients treated with high-dose zinc salt oral lozenges showed significant improvement in symptoms within one day of treatment. Although the sample size was limited, the findings suggest that zinc may play a role in clinical recovery2.
Case-Control Studies
A case-control study evaluated the effectiveness of zinc supplementation in preventing and mitigating COVID-19. The study found that symptomatic COVID-19 infection was significantly higher in the control group compared to the treatment group, suggesting that zinc may be an effective prophylactic agent3.
Zinc Lozenges and Common Cold
While not specific to COVID-19, several studies have examined the efficacy of zinc lozenges in treating the common cold, which shares some symptomatic similarities with COVID-19. A meta-analysis of three trials found that zinc acetate lozenges significantly shortened the duration of common cold symptoms4. Another study found that high-dose zinc acetate lozenges reduced the duration of various common cold symptoms, including nasal discharge, nasal congestion, and cough6.
Limitations and Adverse Effects
Not all studies have found zinc lozenges to be effective. A randomized controlled trial in children and adolescents found no significant difference in the resolution of cold symptoms between the zinc and placebo groups5. Additionally, some studies reported adverse effects such as nausea and bad taste, which could limit the acceptability of zinc lozenges8.