Advancing body contouring: A comprehensive review of intramuscular fat grafting techniques, outcomes, and safety considerations

Intramuscular fat grafting has emerged as a transformative technique in aesthetic surgery, particularly within modern body contouring procedures where high-definition contouring and selective volume enhancement are desired. While subcutaneous fat grafting remains a foundational approach, intramuscular injection has been suggested to provide superior definition, projection, and dynamic contouring in selected anatomical regions. Nevertheless, its clinical adoption remains controversial due to ongoing concerns regarding safety, variable fat retention, and inconsistent reporting of complications. A structured literature search was conducted in PubMed, ScienceDirect, and the Cochrane Library using database-specific combinations of intramuscular- and fat grafting-related terms, yielding 495 reports. Ultimately, 45 studies met the inclusion criteria and were retrieved. Analysis focused on safety, fat retention, and clinical outcomes. The included studies suggested favorable aesthetic outcomes and generally positive reported satisfaction across selected facial, truncal, and extremity applications, although outcome reporting was heterogeneous and often non-standardized. While animal models present conflicting retention data, clinical series have described acceptable volume persistence in selected settings. Safety appeared to be strongly region-dependent. While intramuscular gluteal injection remains associated with a prohibitive embolic risk, non-gluteal ultrasound-guided applications reported low rates of major complications in the reviewed literature, although the available evidence remains limited. In conclusion, this review summarizes reported intramuscular fat grafting techniques and synthesizes the available evidence on outcomes and region-specific safety considerations. Future studies must focus on comparing this approach to subcutaneous grafting in larger cohorts.