Deoxycholic Acid Injection for Submental Fullness: An Anatomy‐Based Narrative Review With Considerations for Off‐Label Lower‐Face Use

Background Deoxycholic acid (DCA) injection is an established minimally invasive treatment for localized submental fat (SMF) reduction. Although clinical trials and systematic reviews support its efficacy, submental fullness is anatomically heterogeneous and may not always represent targetable fat. Aims This narrative review summarizes evidence on DCA injection, emphasizing anatomy‐based patient selection and safety planning for submental treatment and cautious off‐label use. Methods This structured narrative review was guided by the Scale for the Assessment of Narrative Review Articles. PubMed/MEDLINE was searched in August 2026 for evidence on DCA efficacy, mechanism, anatomy, imaging, injection technique, safety, and non‐submental applications. Relevant reference lists were also examined. The literature was organized by mechanism, clinical evidence, anatomy, imaging, patient selection, off‐label applications, and safety. Results DCA produces adipocyte membrane disruption followed by inflammatory clearance and tissue remodeling. The strongest evidence supports SMF reduction in patients with localized superficial subcutaneous fat, particularly preplatysmal fat. Similar fullness may result from deep fat, laxity, platysmal banding, glandular or muscular prominence, soft‐tissue ptosis, skeletal deficiency, or regional atrophy; these contributors require different strategies. High‐frequency ultrasound may assist when clinical examination does not clearly identify the dominant contributor or intended tissue plane, but it is an adjunct rather than a stand‐alone test of candidacy or safety. Evidence for non‐submental applications remains limited. Conclusions DCA should be regarded as an anatomy‐dependent adipocytolytic procedure rather than a general “fat‐dissolving” injection. Careful selection, precise placement, and realistic counseling may improve outcomes, reduce avoidable complications, and support cautious, individualized off‐label use.