People who take zinc supplements within one day of a cold’s onset will reduce the severity and length of illness, according to a review in The Cochrane Library.

A study involving the common cold and zinc lozenges was first introduced in 1984, but conflicting reports were introduced since then. The Cochrane review updates that study and presents data from 15 new studies involving more than 1,300 patients.

The patients who took zinc felt better within 7 days compared to those who took placebos. Children who consistently took zinc lozenges for at least five months caught fewer colds and did not miss as much time from school, according to data.

“This review strengthens the evidence for zinc as a treatment for the common cold,” said lead researcher Meenu Singh of the Post Graduate Institute of Medical Education and Research in Chandigarh, India in a press release. “However, at the moment, it is still difficult to make a general recommendation because we do not know very much about the optimum dose, formulation or length of treatment.”

Click here to read more about this from The Cochrane Library.