What is it about?
Over a dozen placebo-controlled trials on zinc lozenges and the common cold have been carried out with varying results, with the composition of the lozenges and the dose of zinc effectively explaining the variation. In seven RCTs, zinc acetate and zinc gluconate lozenges containing >75 mg/day of elemental zinc shortened common cold duration on average by 33%. A Cochrane review by Nault et al. (2024) analyzed the published trials; however, there were numerous errors in the Cochrane review. Susan Wieland summarized the findings of Nault's Cochrane review; however, she overlooked significant flaws in the Cochrane review that had been pointed out in prior critiques.
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Why is it important?
The common cold is the leading cause of acute morbidity and visits to physicians in high-income countries and a major cause of absenteeism from work and school. Therefore it is particularly worrying that the conclusions of the Cochrane review on zinc for the common cold (2024) are based on flawed statistical analyses, and the critique is ignored in Wieland's summary.
Perspectives
Cochrane reviews are advertised with a slogan (2026): "Trusted evidence. Informed decisions. Better health." However, some Cochrane reviews are seriously flawed and mislead their readers. The Cochrane review by Nault et al. (2024) has severe flaws and should not be trusted when considering the potential role of zinc lozenges for the common cold.
Dr Harri Hemila
Helsingin Yliopisto
Read the Original
This page is a summary of: Misleading summary of the Cochrane review on zinc for the common cold (2024), EXPLORE, September 2025, Elsevier,
DOI: 10.1016/j.explore.2025.103215.
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