Developed jaw tension and headaches from overdoing it. The mewing component alone is probably sufficient — adding conscious cheek and eye engagement was too much.

Full-face orthotropics beyond the tongue
A systematic approach extending mewing into active training of the entire facial posture throughout the day — lip seal pressure, cheek muscle engagement, eye socket and brow positioning, and zygomaticus activation. Promoted in orthotropics communities as a comprehensive approach to facial remodeling through sustained muscular and postural inputs. CONTROVERSY: While proper lip seal and nasal breathing have legitimate support for children during development, the claim that facial muscle engagement can remodel adult bone structure is not supported by clinical evidence. There is real risk of developing habitual muscle tension, bruxism, or TMJ issues from attempting to consciously control facial muscles at all times.
2 verified voices, averaging 3.0 of 5.
Developed jaw tension and headaches from overdoing it. The mewing component alone is probably sufficient — adding conscious cheek and eye engagement was too much.
Some of the posture principles overlap with legitimate facial yoga. The bone remodeling claims are speculative, but improving resting muscle tone probably has some benefit.