High-intensity focused ultrasound, usually abbreviated to HIFU, has become an established non-surgical technology used to improve skin laxity and facial and body contour. Unlike treatments that primarily act on the surface of the skin, HIFU delivers ultrasound energy to predetermined depths beneath the skin, creating small areas of controlled thermal injury while largely sparing the surrounding tissue.The biological response to this controlled heating includes collagen contraction followed by a longer process of collagen remodelling and neocollagenesis. This helps explain why the result is not usually immediate in the way that mechanically lifting tissue would be. Improvement develops progressively during the weeks and months following treatment.HIFU is not the same as every ultrasound tightening technologyScientific publications frequently use the terms HIFU, focused ultrasound, microfocused ultrasound and microfocused ultrasound with visualisation interchangeably. They are related technologies, but they are not identical. For this review we have concentrated on studies specifically investigating high-intensity focused ultrasound and have not used studies of microfocused ultrasound with visualisation, or MFU-V, as evidence for HIFU. We have also excluded studies of high-intensity parallel-beam ultrasound where the ultrasound was specifically described as non-focused. This distinction is important when interpreting claims about the evidence supporting HIFU.Overall evidence for HIFUA 2025 systematic review by Haykal and colleagues examined clinical evidence for HIFU in aesthetic skin tightening and body contouring. Across the literature reviewed, HIFU demonstrated improvement particularly in the lower face, neck and periorbital region. The authors reported improvements in skin laxity in the region of approximately 18% to 30% in included studies, while generally finding a favourable safety profile.An earlier systematic review by Kumar and colleagues evaluated prospective and experimental HIFU studies for facial and body contouring. Eleven studies met the review criteria. Nine investigated abdominal treatment and only two focused on the face and neck, illustrating an important limitation of the evidence: there are considerably fewer well-controlled facial studies than the popularity of HIFU might suggest. Nevertheless, the overall findings were positive, with the authors concluding that HIFU was a safe, minimally invasive treatment capable of producing measurable facial and body contouring effects.HIFU for the face and jawlineOne of the more useful clinical studies evaluated HIFU treatment of the face and neck in 75 patients. Aşiran Serdar and colleagues treated patients using focal depths of 3 mm and 4.5 mm and independently assessed changes three months later. Improvement was evaluated separately in the nasolabial area, jawline, submental area and neck. Physician-rated improvement was reported in more than 80% of patients in each area, while patient satisfaction exceeded 78%.This study therefore supports the use of HIFU for patients with facial laxity, particularly where the concern involves loss of definition around the lower face, jawline and beneath the chin. It is important, however, to interpret these results appropriately. HIFU produces a tightening and remodelling effect. It should not be presented as equivalent to a surgical facelift, nor would we expect the same magnitude of tissue repositioning.HIFU for the neckThe neck is one of the better-supported anatomical areas for HIFU. The facial and neck study described above found clinically visible improvements following treatment. Further evidence comes from a prospective study by Han and colleagues involving 102 participants. Thirty-four patients were allocated to each of three treatment groups covering the periorbital region, perioral region and neck.Participants received three HIFU treatments at two-week intervals using a 5.5 MHz transducer with a 2 mm focal depth. Objective measurements of skin elasticity, three-dimensional skin analysis, wrinkle assessment and patient-reported aesthetic improvement all demonstrated significant improvements at follow-up. The results support the use of appropriately selected HIFU parameters for neck wrinkles and laxity.HIFU around the eyes and under the eyesThere is genuine clinical evidence supporting HIFU treatment of the periorbital area, but this needs to be described carefully.In the prospective study by Han and colleagues, HIFU produced statistically significant improvements in periorbital wrinkles and objective measurements of skin elasticity at follow-up. A separate split-face study by Byun and colleagues also found that HIFU treatment significantly improved the depth of eye wrinkles and the degree of sagging around the eye area.These studies support the use of HIFU for selected patients with periorbital wrinkles and mild skin laxity. However, this does not mean that HIFU has been proven to treat every problem commonly described as an "under-eye concern." The current evidence does not establish HIFU as a treatment for tear-trough hollowing, pigmentation-related dark circles or prominent lower-eyelid fat pads. These problems have different anatomical causes and may require completely different approaches.For this reason, we prefer to describe HIFU as an option for periorbital skin laxity and wrinkles rather than simply claiming that HIFU "treats under-eye bags."HIFU for skin tightening on the bodyThe evidence for body tightening is promising, although the clinical studies are generally smaller. Choi and colleagues investigated HIFU on several anatomical sites including the upper arms, lower abdomen, thighs and calves. Although this was a very small pilot study involving only six women, blinded investigators found clinical improvement four weeks after treatment and objective Cutometer measurements demonstrated significantly improved skin elasticity at the treated sites.A larger prospective study by Ko and colleagues included 32 patients treated on the cheeks, lower abdomen and thighs. Skin elasticity improved significantly at all treatment sites twelve weeks after HIFU treatment. Both investigator and patient Global Aesthetic Improvement Scale assessments also demonstrated improvement.These findings suggest that HIFU can improve skin elasticity and tightening in selected body areas including the abdomen, thighs and upper arms. However, the evidence base for body skin tightening remains smaller and more heterogeneous than the evidence for facial treatment. Another complication is that deeper HIFU treatment can also affect subcutaneous adipose tissue. Studies describing reductions in body circumference therefore cannot automatically be interpreted as evidence of skin tightening alone.How quickly do results develop?The clinical research supports the concept that HIFU results develop progressively rather than appearing entirely on the day of treatment. Studies have commonly assessed outcomes between approximately four weeks and three or four months after treatment, with measurable improvements becoming apparent during this period. This corresponds with the biological process of collagen remodelling following thermal stimulation. Patients may sometimes notice an earlier feeling of tightening, but the principal regenerative response takes longer to develop.Safety and side effectsAcross the studies reviewed, HIFU generally demonstrated a favourable safety profile when performed appropriately. Temporary discomfort during treatment is common.For example, in the 75-patient facial and neck study, pain during treatment was reported by approximately one quarter of patients. Temporary redness occurred less frequently. One patient experienced temporary numbness around the mandibular area, which resolved spontaneously within ten days. In the body studies, discomfort immediately after treatment was reported, while persistent pain and serious adverse events were uncommon. The prospective study investigating the periorbital, perioral and neck regions reported no permanent adverse effects during the follow-up period.This should not be interpreted as meaning that HIFU is risk-free. Ultrasound energy is being delivered into deeper anatomical structures, making appropriate patient selection, knowledge of facial anatomy, correct treatment depth and suitable energy settings important.Limitations of the evidenceAlthough the accumulated literature is encouraging, HIFU research has several important weaknesses. Many studies contain relatively small numbers of patients. Some lack untreated controls or sham-treatment groups. Different studies use different machines, frequencies, focal depths, energy settings and numbers of treatment lines, making direct comparison difficult. Follow-up is also frequently measured in months rather than years.A further problem is inconsistent terminology. Publications may describe technically different forms of focused ultrasound under similar names. Consequently, it is not scientifically justified to assume that every device marketed as "HIFU" will reproduce the results obtained with a particular device and treatment protocol used in a clinical study.ConclusionThe available clinical literature supports HIFU as a credible non-surgical option for patients with mild to moderate skin laxity who are looking for gradual tightening rather than surgical lifting. The evidence is strongest for:lower-face and jawline tightening;submental laxity;neck laxity and wrinkles;periorbital wrinkles and mild laxity; andselected body areas including the abdomen, thighs and upper arms.The studies suggest that improvement occurs progressively through collagen remodelling and can be demonstrated both clinically and through objective measurements of skin elasticity. HIFU should nevertheless be presented realistically. It does not reproduce the magnitude of lifting achieved by surgery, results vary between individuals and devices and treatment protocols are not yet standardised across the industry. For appropriately selected patients, however, the available evidence supports HIFU as a useful non-surgical treatment for improving skin firmness, laxity and contour with relatively little downtime.Selected ReferencesHaykal D, Sattler S, Verner I, Madhumita M, Cartier H. A Systematic Review of High-Intensity Focused Ultrasound in Skin Tightening and Body Contouring. Aesthetic Surgery Journal. 2025. doi:10.1093/asj/sjaf053Kumar V, Jain A, Vadera S, Shome D, Kapoor R. Effectiveness of HIFU Therapy for Nonsurgical Facial and Body Contouring: A Systematic Review of Prospective and Experimental Studies. Plastic and Reconstructive Surgery. doi:10.1097/PRS.0000000000009912Aşiran Serdar Z, Aktaş Karabay E, Tatlıparmak A, Aksoy B. Efficacy of high-intensity focused ultrasound in facial and neck rejuvenation. Journal of Cosmetic Dermatology. 2020;19:353-358. doi:10.1111/jocd.13008Han HS, Park JW, Kim SY, Yoo KH, Choi SY, Kim BJ. Safety and efficacy of high-intensity focused ultrasound for treatment of periorbital, perioral, and neck wrinkles. Dermatologic Therapy. 2022;35:e15420. doi:10.1111/dth.15420Choi SY, No YA, Kim SY, Kim BJ, Kim MN. Tightening effects of high-intensity focused ultrasound on body skin and subdermal tissue: a pilot study. Journal of the European Academy of Dermatology and Venereology. 2016;30:1599-1602. doi:10.1111/jdv.13713Ko EJ, Hong JY, Kwon TR, et al. Efficacy and safety of non-invasive body tightening with high-intensity focused ultrasound (HIFU). Skin Research and Technology. 2017;23:558-562. doi:10.1111/srt.12371Byun JW, Kang YR, Park S, Hong W. Efficacy of radiofrequency combined with single-dot ultrasound for skin rejuvenation: a non-randomized split-face trial with blinded response evaluation. Skin Research and Technology. 2023;29:e13452. doi:10.1111/srt.13452