Matrixx Initiatives, Inc., the manufacturer of Zicam Cold Remedy zinc products, said that reports alleging anosmia, or loss of smell, in a small number of patients using zinc gluconate intranasal gels for the treatment of the common cold are completely unfounded and misleading. At this time, the company is not aware of any investigation by a regulatory body with regard to the product.

The company assures that Zicam Cold Remedy intranasal zinc gluconate products are manufactured and marketed according to Food and Drug Administration guidelines for homeopathic medicine.

In no clinical trial of intranasal zinc gluconate gel products has there been a single report of lost or diminished olfactory function (sense of smell). Rather, the safety and efficacy of zinc gluconate for the treatment of symptoms related to the common cold have been well established in two double-blind, placebo-controlled, randomized clinical trials. In fact, in neither study were there any reports of anosmia related to the use of this compound. The overall incidence of adverse events associated with zinc gluconate was extremely low, with no statistically significant difference between the adverse event rates for the treated and placebo subsets.

A multitude of environmental and biologic influences are known to affect the sense of smell. Chief among them is the common cold. As a result, the population most likely to use cold remedy products is already at increased risk of developing anosmia. Other common causes of olfactory dysfunction include age, nasal and sinus infections, head trauma, anatomical obstructions, and environmental irritants.

A few researchers have attempted to link nasal products containing zinc to the onset of anosmia. However, this hypothesis is based on data from polio studies conducted in the 1930s using a concentrated zinc sulfate solution. Current nasal products, such as Zicam Cold Remedy, contain zinc gluconate, which is an entirely different compound.