Nasal breathing is the most under-diagnosed variable in a tired face and a soft mid-face. Here is what the mechanism actually is, what the studies show, and where the claims get too loud.
Mechanism
Resting tongue posture on the roof of the mouth generates upward force on the maxilla. Closed lips maintain that posture. Nose-only breathing keeps the mouth closed by default.
Realistic timelines
Sleep quality shifts inside a week. Morning puffiness drops in two. Actual structural change is measured in seasons, not weeks, and requires the posture to be genuinely default, not enforced.
