Do Different High‐Intensity‐Focused Ultrasound Frequencies Have Different Effects? A Histological Analysis Correlated With Patients' Subjective Assessments

ABSTRACT Background High‐intensity‐focused ultrasound (HIFU) has emerged as a noninvasive approach for facial rejuvenation, offering benefits such as collagen synthesis and subcutaneous fat reduction. However, the differential effects of varying HIFU frequencies on specific skin layers remain underexplored. Aims To evaluate the histological effects of different HIFU frequencies and correlate these findings with patient‐reported outcomes, thereby optimizing clinical applications. Patients/Methods Histological analysis was performed on pig skin treated with HIFU at specific depths (2.0, 3.0, 4.5, and 6.0 mm) using the Ultraformer MPT device. Collagen types I and III, elastin fibers, and fat reduction were assessed using immunohistochemistry, Victoria blue staining, and Oil Red O staining. Additionally, 50 Asian female participants aged 30–60 years with skin laxity underwent HIFU treatment. Clinical outcomes were evaluated using standardized photographs, the Global Aesthetic Improvement Scale (GAIS), and a modified Rosenberg Self‐Esteem Scale. Results Histological analysis revealed increased collagen and elastin fiber synthesis and significant fat reduction post‐HIFU. Clinical outcomes corroborated these findings, with 85.3% of participants reporting overall satisfaction and 70.6% noting improvements in facial contouring. Self‐esteem assessments indicated a positive psychological impact, with 64.7% of participants expressing enhanced confidence. Conclusions HIFU treatment at varying frequencies induces significant histological and clinical improvements, demonstrating its efficacy for skin rejuvenation. This study underscores HIFU's dual role in enhancing physical appearance and psychological well‐being, supporting its integration into patient‐centric aesthetic care.