For snoring and apnea: yes. For a new jaw: no evidence.

Tongue, throat and mouth exercises (myofunctional therapy) have real evidence for one thing: snoring and sleep apnea, done with a sleep doctor or therapist. Using them (or "mewing") to reshape an adult jaw or cheekbones has no trial behind it.
S Evidence: strong. Large trials or many studies, pointing the same way.
C Evidence: contested. The research disagrees. Named, so you can stop worrying about it.
Myofunctional therapy roughly halved apnea events in adults with sleep apnea and reduced snoring and sleepiness (Camacho et al. 2015, meta-analysis, 9 adult studies, 120 patients, 🟢) · adult bone reshaping from tongue posture or chewing: no trials (🔴).
Not medical, legal or financial advice.
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