Study Finds These At-Home COVID-19 Remedies Probably Won't Work

High doses of vitamin C and zinc do not help fight off or lessen the symptoms of COVID-19, according to a new study published in JAMA Network Open. Researchers from the Cleveland Clinic examined the effects of zinc and vitamin C supplements on 214 people recovering from COVID-19 at home (via CNN).

The clinical trial randomly divided the patients into four groups, giving the first group high doses of vitamin C and the second group high doses of zinc. The third group of patients received high doses of both supplements, while the fourth acted as the control group and only received standard care. After six months, researchers found that the supplements failed to improve the patients' symptoms and ended the trial early.

"When we began this trial, there was no research to support supplemental therapy for the prevention or treatment of patients with COVID-19," Dr. Milind Desai, a cardiologist at the Cleveland Clinic and the co-principal investigator of the study said in a press release. "While vitamin C and zinc proved ineffective as a treatment when clinically compared to standard care, the study of other therapeutics continues."

The downside of taking too much zinc and vitamin C

At the start of the pandemic, vitamin C sales rose by 146 percent and zinc sales soared by 255 percent, according to The New York Times. That's because the two supplements have long been praised as cold and flu remedies due to their reputation for supporting and boosting the immune system. Research has shown that vitamin C can shorten the duration of colds by 8 percent in adults and 14 percent in children, while zinc may also reduce the length of a cold if taken one day before the onset of any symptoms.

That's why researchers at the Cleveland Clinic were eager to study the supplements' impact on COVID-19 symptoms. However, high doses of both supplements can cause troubling side effects. The patients in the clinical trial taking high doses of zinc, vitamin C, or both experienced nausea, vomiting, and stomach cramps, while those in the standard care group did not. These are all typical side effects of consuming too much zinc and vitamin C. Additional symptoms include heartburn, headache, dry mouth, and loss of appetite.

"It's good to look at the data like this," Dr. Suma Thomas, a specialist in cardiovascular medicine at the Cleveland Clinic and co-principal investigator of the study, told Healthline. "People can now weigh the cost and possible side effects with the results and make an informed decision."