Different zinc lozenges let your body absorb zinc differently. Some, like zinc acetate, let you use all the zinc, while others don't let you use any at all.

Different zinc lozenges have different amounts of the active form of zinc, and only the active form fights viruses.

Different ingredients in zinc lozenges can change how well they work, even if the amount of zinc is the same, because some ingredients stick to the zinc and make it harder for your body to use it.

Different types of zinc lozenges release zinc in different amounts when they dissolve in your mouth, and this affects how well they work in studies.

Some studies show zinc gluconate supplements are absorbed better than another common form, but other studies find no real difference in zinc levels in people's blood. The results are mixed.