Results/Conclusions

Oral lozenges have been shown to reduce the symptoms of the common cold in fifty percent of the studies, with reference to the duration of symptoms. However, half of the studies have shown zinc lozenges to be of little to no benefit. These studies may not have yielded positive results due to their particular zinc formulation, although, studies with similar preparations have yielded both positive and negative results.

Nasal preparations have also yielded both positive and negative results. One of the studies examining the nasal spray was shown to be ineffective, probably due to a low dose. The nasal gel spray has been show to be effective in newer studies.

The most complete systematic review of the literature showed no benefit of oral lozenges and found one study that showed positive results of nasal gel formulations.

Thus at this time, zinc for cold symptoms and reduction of cold duration can not be recommended. Further studies are needed to determine if zinc possesses significant antiviral action.