Question: Can Zicam cause you to lose your sense of smell?
A reader recently emailed me and asked about Zicam® causing a person to lose their sense of smell. I thought it was an interesting question that more people may be curious about. So, here is what I found.
Answer:
A lawsuit that was brought against the manufacturers of Zicam® and Cold-Eeze® nasal gels was settled in January 2006. Hundreds of people were involved in the lawsuit and claimed they lost their sense of smell after using the product. In a $12 million settlement, the company admitted no wrongdoing or admission that their products caused loss of the sense of smell.
A lot has been made from this lawsuit and accusation against Zicam and Cold-Eeze. The internet has been overrun by emails and websites claiming that these products will cause people to lose their sense of smell. I have personally received numerous emails from people who say they lost their sense of smell after using Zicam.
But my goal is to look at what studies have been performed and give you the best information that is available about the safety and efficacy of these products. So, first we will look at safety.
- There have been two notable studies performed and published with regards to this issue of anosmia (loss of the sense of smell). The first was performed by Dr. Burton Slotnick and tested the effect of zinc sulfate, which is different from the zinc gluconate in Zicam, on the smell center in mice. That study found that there was a temporary loss of the sense of smell when mice were given high doses of zinc sulfate.
- The second study was also performed by Dr. Slotnick and a group of researchers but was supported in part by a grant from Matrixx, Inc., the PR firm for Zicam. This more recent study tested the effect of zinc gluconate, the active ingredient in Zicam, on mice. The results of that study showed that there was only a partial, temporary loss of the sense of smell in mice when given extremely large doses (much higher than the normal dose for humans). However, the damage was reversed within a couple of weeks.
- It is important to point out that both of these studies were performed on mice and we must be cautious when applying results of testing on animals to humans. Because there have been no large scale studies performed on humans, we cannot say conclusively that the product either causes or does not cause anosmia in humans.
The second issue to look at concerning Zicam and Cold-Eeze is efficacy. Neither product is regulated by the FDA yet both claim to shorten the duration of the common cold. They claim that this was proven in a study by the Cleveland Clinic, a research facility. However, according to the study, the effects of zinc nasal spray on the common cold are still inconclusive. If you have used these products without adverse effects, that is wonderful. As with any medication, you will have to decide for yourself whether the benefits outweigh the risks, either real or perceived.
The lack of a large-scale study on these medications is concerning. For something that is so controversial, I believe the public would greatly benefit from a large study on these products' side effects. What do you think? Feel free to Email me or join the ongoing discussion in the Cold and Flu Forum about Zicam.
Sources:
Mossad, Sherif B. "Upper Respiratory Tract Infections." The Cleveland Clinic Disease Management Project 29 July 2005. 03 Nov 2006.
Slotnick B, Sanguino A, Husband S,
Marquino G, Silberberg A. Olfaction and olfactory epithelium in mice
treated with zinc gluconate. Laryngoscope. 2007 Apr;117(4):743-9.
McBride K, Slotnick B, Margolis FL. Does intranasal
application of zinc sulfate produce anosmia in the mouse? An
olfactometric and anatomical study. Chem Senses. 2003
Oct;28(8):659-70.
