Zinc, vitamin C show no benefit against COVID-19

In adults with COVID-19 who were not sick enough to be hospitalized, high doses of zinc or vitamin C, or both, failed to improve their symptoms or speed their recovery, researchers reported on Friday in JAMA Network Open.

They randomly assigned 214 patients to 10 days of treatment with either a high dose of zinc, vitamin C, both, or neither.

Everyone also received standard supportive treatments from their healthcare providers. There was no significant difference between the groups in the number of days required to reach a 50% reduction in symptoms like fever, cough, shortness of breath, and fatigue.

There was also no difference in the number of days until patients no longer had severe symptoms, in need for other prescribed medications, or in rates of hospitalizations and deaths.

Zinc and vitamin C (ascorbic acid) supplements “cannot be recommended” to ease the course of COVID-19 in outpatients, the researchers concluded.

“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,” they said.