HIFU is one of those modalities that’s easy to discuss in general terms but harder to describe precisely. Patients usually come in seeking “tightening,” yet in daily practice, we often see two distinct patterns: in some, the dominant effect is skin firming; in others, the more noticeable change is contouring — and even a degree of facial slimming, particularly in the lower third [1, 2]. That naturally raises the question: is this driven by baseline facial anatomy, or by how energy is distributed across tissue depths?

In 2025, Hwang et al. published a clinically oriented study in the Journal of Cosmetic Dermatology that directly addresses this issue: the authors propose that HIFU is not a single effect but a spectrum of tissue responses that varies with treatment depth [3]. They performed histologic analysis in a porcine skin model and then compared those findings with both patient- and physician-based photo-assessments at 3 months.

What the authors studied

In the experimental arm, porcine skin was treated with HIFU at different target depths (2.0, 3.0, 4.5, and 6.0 mm) using Ultraformer MPT. The investigators evaluated collagen synthesis (types I and III via immunohistochemistry), elastin changes (Victoria blue staining), and adipose tissue reduction (Oil Red O staining).

In the clinical arm, 50 women aged 30–60 with skin laxity underwent HIFU treatment (34 completed follow-up). Outcomes were assessed using GAIS and subjective patient satisfaction, along with two questions related to self-perception and confidence.

Key findings

Immunohistochemistry at 30 days showed an apparent increase in collagen types I and III, supporting ongoing remodeling of the dermal extracellular matrix. Victoria blue staining also demonstrated focal areas in the deep dermis that the authors interpreted as regeneration/strengthening of elastin fibers (marked with red circles in the original figure). This is a helpful visual when explaining to patients that the goal is not “pulling the skin tight,” but initiating a remodeling process that unfolds over time [1, 4].

Oil Red O staining highlighted adipose structures, and post-treatment samples showed a noticeable reduction of adipose tissue in the treated area. In other words, HIFU may produce not only a dermal tightening effect but also changes in the subcutaneous fat compartment — making the “slimming” perception clinically plausible [1, 5].

What patients reported — and why it matters in consultation

Among the 34 patients who completed follow-up:

• 85.3% were satisfied overall;
• 70.6% reported improved contouring and slimming in the treated area;
• 64.7% were satisfied with lifting/tightening.

An additional point consistent with a patient-centered framework: 64.7% reported more positive feelings about themselves, and 61.8% reported feeling more satisfied with themselves/their appearance overall.

Practical takeaways: translating the paper into day-to-day practice

This study is valuable because it helps clinicians explain mechanisms and expected outcomes more accurately, reducing the risk of disappointment.

1. In consultation, it can be helpful to frame outcomes as two parallel “stories”: a dermal component (collagen/elastin remodeling and perceived firmness) and a subcutaneous component (contouring/volume change). The paper provides visual support for both mechanisms.
2. For patients at risk of volume deficiency or those worried about looking “hollow,” be explicit that part of the effect may involve the fat compartment — and that this is not always desirable.
3. Set timelines appropriately: tissue remodeling is not an immediate event, and meaningful assessment often makes more sense over several months.

Finally, keep the limitations in mind: the clinical arm lacked a control group, there was attrition by the final follow-up, and the histology was performed in a porcine model. None of this negates the paper’s usefulness, but it does limit how definitive the conclusions can be. Practically, the study functions best as a mechanism-informed framework — and a strong communication tool for setting expectations.

References

1. Hwang Y., Wan J., Yi K.-H. Do different high-intensity-focused ultrasound frequencies have different effects? A histological analysis correlated with patients' subjective assessments. J Cosmet Dermatol 2025; 24: e70069. https://doi.org/10.1111/jocd.70069
2. Ayatollahi A., Gholami J., Saberi M. et al. Systematic review and meta-analysis of safety and efficacy of high-intensity focused ultrasound (HIFU) for face and neck rejuvenation. Lasers Med Sci 2020; 35(5): 1007–1024.
3. Chan N.P. Shek S.Y., Yu C.S. et al. Safety study of transcutaneous focused ultrasound for non-invasive skin tightening in Asians. Lasers Surg Med 2011; 43(5): 366–375.
4. Alam M., White L.E., Martin N. et al. Ultrasound tightening of facial and neck skin: a rater-blinded prospective cohort study. J Am Acad Dermatol 2010; 62(2): 262–269.
5. Suh D.H., Shin M.K., Lee S.J., et al. Intense focused ultrasound tightening in asian skin: clinical and pathologic results. Dermatol Surg 2011; 37(11): 1595–1602.