Vitamin C and zinc don’t do anything to help coronavirus patients, a Cleveland Clinic team reported Friday.
Their research is the first major randomized study looking at the popular supplements, given under medical supervision, and it found even high doses did nothing to help patients recover from Covid-19.
The team at the Cleveland Clinic health system randomly assigned 214 patients to get varying doses of ascorbic acid, commonly known as vitamin C, and zinc, between April and October of last year.
“In this randomized clinical trial of ambulatory patients diagnosed with SARS-CoV-2 infection, treatment with high-dose zinc gluconate, ascorbic acid, or a combination of the two supplements did not significantly decrease the duration of symptoms compared with standard of care,” the team wrote in the journal JAMA Network Open.
“Most consumers of ascorbic acid and zinc are taking significantly lower doses of these supplements, so demonstrating that even high-dose ascorbic acid and zinc had no benefit suggests clear lack of efficacy,” Dr. Milind Desai of the Cleveland Clinic and colleagues wrote.
“In addition, administering supplements with unproven benefit can be detrimental due to adverse effects. Zinc has been shown to cause a metallic taste, dry mouth, and gastrointestinal intolerance in high doses. Ascorbic acid can cause gastrointestinal intolerance, and in the current study, a significantly higher proportion of patients in the ascorbic acid subgroups reported adverse effects, including nausea, diarrhea, and stomach cramps.”