Taking zinc lozenges around 80-90 mg per day can shorten how long you have a cold by about one-third, and taking even more doesn't help much more than that.

Taking zinc lozenges with less than 75 mg per day doesn't seem to shorten how long a cold lasts, based on studies comparing them to fake pills. It might only work if you take enough.

Taking high-dose zinc lozenges can shorten how long you have a cold by about 3 days, especially for adults between 20 and 50 years old.

Taking zinc lozenges with a certain amount of zinc each day can help shorten how long a cold lasts in adults by about one-third, based on a big review of studies.

Taking zinc lozenges with a certain ingredient can shorten how long you have a cold by almost half, according to studies on people with real colds.

Taking small amounts of zinc lozenges doesn't really help shorten a cold, but taking larger amounts might actually make you feel better faster.