Mouth breathing means less oxygen.
The scientific consensus is that you should breathe through your nose for optimal health. Even the hairs in your nose are there to filter air before it enters the body. Unfortunately, it can be difficult to ensure you are breathing through your nose when you are asleep! Mouth tape is designed to gently induce nasal breathing while you sleep to help your body function its best while you recover and rest. By nasal breathing while sleeping, research has shown, sleepers on average absorb +18% more oxygen, and retain +40% hydration every night.