Zinc salts tested in lab cells for cold viruses show they might not work well as a medicine because they could be more harmful than helpful.

Zinc lozenges might help with cold symptoms, but lab tests show zinc doesn't really fight cold viruses directly, so there's probably another reason they work.

Taking zinc lozenges doesn't make cold symptoms less severe, according to a study with 273 people who were given cold viruses.

Zinc lozenges don't help reduce how long colds last or how bad they feel, whether you catch a cold naturally or in a study where they give you a cold virus.

Taking zinc lozenges for 5 days raises zinc levels in your blood, showing your body absorbs it, but it doesn't help with cold symptoms.

When adults with cold symptoms take zinc gluconate lozenges, their colds might get better faster, but this only worked in a special test setting and not with real-world colds or different zinc types.