Does mewing really work for a sharper jawline?

Mewing, the deliberate practice of pressing the tongue against the palate, has never been directly studied as an intervention for a sharper jawline in controlled trials. There is simply no scientific research that has examined whether mewing visibly changes the jawline in adults. That is the honest starting point.

What the literature does tell us is this: a low tongue position and mouth breathing have been linked to jaw malformations and irregular dental development in observational research. This association has been established in children, but the studies are observational in nature and do not measure the effect of deliberate correction after the fact.

Correct tongue posture and nasal breathing are described in the specialist literature as beneficial for jaw and facial development in children, when those patterns are still being formed. For adults with a fully developed skeleton the situation is different: the available literature states that skeletal deviations in adults are barely responsive to posture alone, and can sometimes only be corrected surgically.

Healthy older adults show measurable loss of muscle strength and mobility in the lips, tongue and jaw compared with younger adults. Whether that loss has any effect on how sharp the jawline looks has, however, never been studied. The link with appearance is therefore speculative.

In short: the biological reasoning behind mewing is not without foundation, but the leap from 'tongue posture influences growing bones in children' to 'mewing sharpens your jawline as an adult' is not scientifically substantiated. Anyone hoping for a visible change in the jawline as an adult cannot count on that based on the available research.