According to research appearing in the journal, Annals of Internal Medicine (August 15, 2000;133:245-252, 302.), taking zinc may help with the common cold. The research involved 50 people with colds. Subjects either took a zinc lozenge containing 12.8 mg of zinc acetate, or a placebo, every two to three hours for as long as their symptoms persisted. The people in the zinc group reported symptoms for an average of four and a half days. Those who took the placebo reported symptoms lasting eight days.
Subjects reported the severity of the following symptoms: sore throat, sneezing, fever runny nose, congestion, coughing, hoarseness, headaches, or muscle aches. Coughing and runny nose were the symptoms that seemed to respond best to the zinc. Side effects experienced by the group taking the zinc lozenges included dry mouth and constipation.
The study was funded by a company that sells zinc lozenges. There is an important distinction to be made. Zinc treats a zinc deficiency, not colds. Zinc is needed by the immune system and if an individual is deficient in zinc, taking zinc will help the immune system. Since zinc deficiency is fairly common, many people with colds who take zinc respond well. If there is no zinc deficiency, taking zinc may not help much.