Does zinc actually help fight cold symptoms?

Learn how to manage the benefits and drawbacks of zinc for your health before taking it to fight off cold symptoms.
Whether taken as an oral lozenge or an intranasal spray, zinc is a popular cold remedy. It is said to lessen the symptoms of a cold, but there can also be side-effects to watch out for.

Some studies have shown that zinc, usually zinc gluconate or zinc acetate, can have a positive effect on colds. For example, zinc has been used to fend off a cold before it starts, with moderate success. It can also moderately decrease both the severity and the duration of cold symptoms.

None of these studies have shown zinc to be a sure-fire way of avoiding colds, and zinc does not "cure" a cold. It also does not work for the flu or other illnesses.

Based on the evidence, zinc's effectiveness against colds seems to be due to it either improving the body's ability to fight illness, or weakening cold-causing rhinoviruses.

If using zinc for a cold, it's advisable to use more than 75 milligrams daily. Anything lower than that is likely to be ineffective.

Some experts have said the effect zinc has on colds may not be strong enough to make a real impact. Most studies have shown that zinc only decreases severity of cold symptoms mildly, and may shorten a cold's length by a day or so. Some feel these benefits are outweighed by zinc's side-effects. Still others have questioned the size or methodology of supportive studies.

One of zinc's most common side-effects at doses used to treat colds is nausea. Taking it along with food can help.

Some zinc products, particularly intranasal ones, have been linked to anosmia, or a loss of smell. This anosmia can last weeks or months, or can even be irreversible. While no intranasal zinc products are approved for use in Canada, Health Canada has issued a warning to avoid foreign intranasal zinc products for this reason.

Finally, while it isn't a side-effect per se, zinc is notorious for tasting extremely unpleasant. Taking it along with food can help prevent this side-effect too.

Ultimately, the decision whether to take zinc is in consumers' hands, but remaining educated about how to manage the benefits and drawbacks of zinc for your health can be helpful.