Swallow Zinc Pills Instead of Sucking Zinc Lozenges? Nah

Have you stocked up on zinc lozenges for the coming cold season? You may have learned in middle school that nothing you take will change the course of a cold. However, that’s no longer true. Science has found that zinc can make a difference, even though it’s not dramatic.

What Is the Story on Zinc and Quercetin for a Cold?

Q. I have read that zinc lozenges are good against colds, especially if used together with vitamin C and quercetin. Is there any proof that this combination would be beneficial for the immune system?

A. There are data supporting the benefits of both zinc and vitamin C against upper respiratory tract infections, aka colds (European Journal of Clinical Nutrition, April, 2017).

Scientists have conducted few studies on quercetin for fighting infections. One study did not show a difference in rates of illness or symptoms (Pharmacological Research, Sept. 2010).

On the other hand, a study conducted in China showed that quercetin has activity against influenza viruses in cell culture (Viruses, Jan. 2016). We will need to see large, well-controlled clinical trials to learn whether this natural product can improve immune response and shorten the duration of viral infections.

Are Zinc Lozenges Safe?

Q. If I feel a cold coming on, I take zinc. I myself don’t have any side effects from it.

However, I recommended it for my son once and it made him very nauseated. Now, of course, he won’t take my advice for any remedy. The nausea side effect of zinc is real, but not everyone suffers from it.

A. Doctors have been debating the pros and cons of zinc to prevent or treat common colds for a long time. However, the scientific evidence keeps building that zinc can help fight these respiratory tract viral infections.

The most recent research is a meta-analysis of 28 randomized controlled trials published in BMJ Open (Nov. 2, 2021). In comparison with placebo, zinc prevented five colds per 100 person-months. When people took zinc to treat rather than prevent a cold, they got better about two days sooner, on average.

Some people reported nausea as a reaction. As your son can attest, nausea may be more of a problem for some than for others.

Why Bother with Zinc Lozenges if They Cause Nausea?

Q. I usually enjoy your column but your answer to one question sounded really dumb. A reader with a cold asked how to get rid of the terrible taste and nausea caused by zinc lozenges, and you said there’s no way around this dilemma.

It seems to me there’s a ludicrously simple solution: just swallow the thing! Presumably, the zinc lozenge’s effects against a cold are not caused by the act of sucking on it, but by its ingredients.

The History of Zinc Lozenges:

 A. The reason people have focused on zinc lozenges for colds is fascinating. One little girl with leukemia in a Texas hospital refused to swallow a zinc pill. Instead, she held it in her mouth until it dissolved. Over the next few hours, the cold she was catching completely disappeared.

This observation intrigued the doctors and a more extensive study was conducted. The results were impressive.

Subsequent studies of zinc lozenges against the common cold have had mixed results. Some showed benefit while others did not.

So far as we know, there has been no good study comparing zinc pills to zinc lozenges. Here is a fairly technical explanation as to why zinc lozenges work and other formulations don’t.

It was published in the Expert Review of Respiratory Medicine (June, 2012):

“The fact that the first observation of the rapid action of zinc lozenges against colds occurred in a child with T-cell leukemia and with no functional immune system due to chemotherapy is a good indicator that more is involved. There is a local mechanism of action: the mouth-nose biologically closed electric circuit (BCEC), which appears to explain the rapid therapeutic response to zinc lozenges. It moves electrons from the nose into the mouth and, in response to the electron flow, it moves positively charged metal ions, such as ionic zinc, from the mouth into the nose…

“Considering these properties, the observation that zinc lozenges releasing positively charged ionic zinc shorten colds in a dose-response manner can be seen in a more plausible light. Orally ingested forms such as tablets, liquids and syrups do not have these properties and therefore, according to my research, are not effective.”

In light of this theory about zinc lozenges, your idea of zinc tablets might not work quite as well as lozenges.

Learn More:

To learn more about zinc lozenges against the common cold and other non-drug approaches, we offer our Guide to Colds, Coughs & the Flu.