It Works for Some, but Not Everyone
There is evidence that mouth taping impacts a person’s ability to sleep more quietly.
The primary evidence for the approach’s effectiveness comes from a single small study from 2015.
Before using the mouth tape, people snored at an average volume of 49.1 decibels (dB). While using the mouth tape, their average snoring volume decreased to 41 dB. For reference, 40dB is considered a quiet house, while 60 dB is considered a normal conversation level. In other words, these were relatively quiet snorers, and the mouth tape made them a little quieter.
The mouth tape also caused them to snore less. Before using the mouth tape, people snored an average of 146.7 times per hour, but they snored 40.0 times per hour while using tape.