Does your co-worker’s first explosive sneeze or your child’s burgeoning cough send you to the store for zinc supplements to protect yourself from catching their cold? It’s true that some studies have found that zinc supplements may shorten the duration of a cold, but there’s no proof that it will prevent one, or ease symptoms such as your runny nose or aching head.

And beware: Zinc has side effects, too. Nevertheless, consumers spent about $108 million on zinc supplements in 2014, according to the Nutrition Business Journal.

Here are six reasons to keep the cash in your pocket and skip the zinc this cold season.

1. Zinc Won’t Relieve Your Cold Symptoms
Zinc is no magic bullet. Research published in the British Journal of Clinical Pharmacology found that regularly sucking on high doses of zinc lozenges (totaling 80 to 90 mg per day) throughout a cold may shorten it by almost three days, but other research has not been nearly as positive. And, says Consumer Reports' chief medical adviser Marvin M. Lipman, M.D., "Zinc won't ease cold symptoms."

2. This Supplement Has Side Effects
While slicing a few days off your suffering may sound great—and there is evidence that zinc ions have an antiviral effect, at least in a petri dish—the reality is that taking zinc can have some pretty unpleasant side effects. These include leaving a foul taste in your mouth, vomiting, stomach cramps, diarrhea, and other problems—which may make the treatment worse than the disease, Lipman says.

3. Zinc Can Be Toxic
A healthy adult woman should get a minimum of 8 milligrams (mg) of zinc per day, and adult men 11 mg, but that amount is easily obtained through a healthy diet that includes zinc-rich foods such as poultry, red meat, and fortified breakfast cereal.

In fact, the National Institutes of Health advises that unless you’re taking zinc for medical reasons under the care of a doctor, the maximum daily limit you should get is 40 mg. Too much can cause side effects.

4. It Can Interact With Your Other Meds
Zinc has been shown to interact with various prescription medicines. For example, take it with tetracycline or quinolone antibiotics such as ciprofloxacin (Cipro and generic) and you’ll reduce the amount of both the zinc and the antibiotic that your body absorbs. It can also interfere with the absorption of penicillamine (Cuprimine, Depen), a drug used to treat rheumatoid arthritis and Wilson’s disease (a rare genetic disorder).

5. Zinc Can Cause Health Problems
Getting too much zinc may increase the risk for prostate cancer, lead to copper deficiency and neurological problems, and reduce levels of HDL (good) cholesterol. What’s more, zinc products may also contain cadmium (another metal that is chemically similar and occurs alongside zinc in nature), and long-term exposure to high levels of cadmium can lead to kidney failure.

6. You Might Lose Your Sense of Smell
Avoid using zinc in the form of nasal preparations, which can make you lose your sense of smell. Several years ago, the Food and Drug Administration took several zinc nasal products off the market after receiving more than 130 reports from people who had used certain nasal Zicam Cold Remedies and lost their sense of smell—some permanently.

On balance, staying hydrated and getting plenty of rest will do more to help you recover than any supplement—and a bowl of chicken soup won’t hurt either.

Editor's Note: An earlier version of this article cited a 2014 review published in JAMA that was retracted in December 2016.