Does taking zinc really cure the common cold?
Zinc is listed in the pharmaceutical literature as "possibly effective" when used as a lozenge
for decreasing the duration of the common cold in adults. The majority of studies show a
significant decrease in the duration of symptoms of the common cold when adults take zinc
gluconate or acetate lozenges providing 9-24 mg elemental zinc per dose. However, not all
studies have been positive.
The reason for these different findings is not clear, but might be due to differences in zinc formulations and study methodologies. In some cases, flavoring agents such as citric acid, mannitol, and sorbitol might chelate zinc and decrease zinc ionization. Since zinc ionization is thought to be important for benefit, this could decrease effectiveness. Some of the positive studies have also been criticized for inadequately blinding the unpleasant, distinctive taste of zinc.
Overall, zinc lozenges, such as Cold-Eeze®, seem to be beneficial for reducing duration of symptoms of the common cold in adults. Zinc lozenges do not seem to be effective for children.