(CNN) – Think your hand sanitizer is an iron clad defense against germs?
According to a new study, that handy bottle of ethanol-based sanitizer may be giving you a false sense of security.
For example, if you blow your nose then put sanitizer on your hands it probably won’t kill cold and flu bugs.
According to the study, it’s because your fingers are still wet with mucus.
If you think that’s gross, listen to how the Japanese researchers came to their conclusion.
They dabbed wet mucus from people infected with influenza a onto the fingertips of volunteers, then applied hand sanitizer.
The ethanol didn’t kill the flu virus unless it was left on for a full four minutes.
However, the results of the new study are in contrast to many others showing ethanol-based disinfectants are effective against the spread of germs.