Zinc Acetate Lozenges for the Treatment of the  Common Cold: A Randomized Controlled Trial  

Harri Hemilä, Jari Haukka, Marianne Alho, Jussi Vahtera, and Mika Kivimäki 

 When used for 5 days after the onset of symptoms, a commercially available zinc acetate lozenge  was ineffective in treating the common cold. While taste has been a frequent complaint in previous zinc  lozenge studies, a third of zinc participants reported no negative side effects. Before zinc lozenges may be  commonly marketed for common cold care, further research is required to determine the characteristics of  zinc lozenges that could be clinically effective. 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7045205/