What causes extra skin under tongue?

Extra skin under the tongue, often referred to as a frenum or lingual frenulum, can be caused by a genetic condition known as a frenulum breve, where the frenulum is shorter or thicker than normal. This can restrict tongue movement and may appear as excess skin. Other factors may include developmental variations or conditions such as oral submucous fibrosis. If this extra skin causes discomfort or functional issues, a consultation with a healthcare professional is recommended.