Why Sofwave Stops at 1.5 mm: The Science of SUPERB Ultrasound

Sofwave is a non-invasive ultrasound lifting device in which seven transducers fire parallel ultrasound beams at the same moment, heating a single layer of skin — the mid-dermis, roughly 1.5 mm below the surface. It is easy to assume that a lifting device which reaches deeper is a stronger one, but depth is not a measure of strength. It is a decision about what you intend to treat.

This article explains why Sofwave was designed to stop at 1.5 mm, and what the published studies do and do not support. What follows reflects how the treatment is performed at Coco Clinic. Results and recovery vary between individuals.

What it is

Sofwave was developed by SofWave Medical in Israel. It belongs to the family of treatments that use heat alone — no incision, no injection — to prompt a repair response inside the skin.

It uses ultrasound, as HIFU devices do, but it handles the energy differently. HIFU focuses ultrasound to a point and drives that point deep into the tissue. Sofwave does not focus the energy at all; it spreads it into beams that travel side by side. The manufacturer calls this SUPERB, for Synchronous Ultrasound Parallel Beam.

How it works — seven parallel beams

Focusing ultrasound to a point makes that point very hot, but the tissue between one point and the next is left untouched. SUPERB takes the opposite approach. Seven transducers emit 12 MHz ultrasound in parallel, simultaneously, so a layer is heated as a surface rather than as a scatter of points. The treatment window covers 1 cm × 4 cm at a time.

The frequency itself is part of the design. The higher the frequency, the more the ultrasound is attenuated as it travels, and the less deeply it penetrates. Choosing 12 MHz is already a decision to work in a shallow layer.

What happens in that layer is this. The targeted dermis is heated to 60-70°C for 4-5 seconds per pulse, forming cylindrical zones of thermal coagulation. As the body repairs those zones, it is prompted to produce new collagen and elastin. Energy is adjusted within a 3.0-5.0 J range according to the skin and the patient's comfort; at Coco Clinic we typically start at 3.4-3.6 J.

Throughout, cooling built into the transducer (Sofcool) chills the epidermis, and skin temperature is measured in real time during the session. The layer being heated and the layer being protected are kept separate by design.

Why 1.5 mm — depth is a choice of target, not of strength

Sofwave's thermal effect is confined to a band between 0.5 and 2 mm, centred on the mid-dermis at 1.5 mm. The point worth holding onto is that 1.5 mm is not as far as the device can reach. It is where the device was built to stop.

The reason is that different depths are different targets. The SMAS fascia, further down, is the structural sheet that holds the face up. The mid-dermis at 1.5 mm is the thickness and elasticity of the skin itself. Tightening a fascial layer and treating the skin are not the same task.

Depth also carries a cost. Once energy travels into the subcutaneous layer, it reaches the fat that sits there. That is why people with thin faces, or who have watched their cheeks hollow after an earlier lifting treatment, hesitate over procedures that go deep. Because Sofwave confines its energy to 1.5 mm, it does not reach the fat layer below.

The trade-off is real in the other direction too: Sofwave does not pull the fascia. If laxity has progressed to the point where the structure needs to be lifted mechanically, a HIFU device such as LinearZ does that job, and where the goal is overall tightening and contour, monopolar radiofrequency such as XERF is the better match. Ulthera and Shurink, the names most people know, are also focused-point HIFU devices.

The table sets out where and how each device places energy; it does not imply that one is superior to another. All three are performed at our clinic, and which one suits you depends on skin thickness, fat volume, and how far laxity has progressed.

What the evidence shows

A plausible mechanism is not the same as a demonstrated result, so here are the published studies as reported, with their limitations alongside.

The limitations are equally clear. Sample sizes range from 13 to 80, and follow-up runs only 2-3 months, so evidence for durability beyond 6-12 months remains thin.

One finding deserves particular care. In the histology from Suh et al., the change that reached statistical significance was in elastin density; the change in collagen density did not (p=0.094). For that reason we do not tell patients that Sofwave increases collagen. What the current evidence supports is that the mechanism prompting collagen and elastin renewal is engaged — not more than that.

The timeline runs as follows. A slight tightening may be felt immediately, and any redness or warmth usually settles the same day, allowing a return to normal activity. Visible change begins around 4-6 weeks, as new collagen and elastin form, and peaks at about 3 months. How long it holds afterwards varies considerably with age, skin condition, and lifestyle.

Who it suits

The answer follows from the mechanism. It is worth considering if you have little facial fat and are wary of lifting treatments that go deep, if your cheeks hollowed after a previous lifting procedure, or if fine lines and a sense of thinning skin bother you together. It also suits people who cannot take downtime and need to return to normal activity the same day, or who want to treat a narrower area such as the brow, jawline, or neck.

A session takes about 30-45 minutes including the anaesthetic cream. Plans come in 100, 200, and 300 shots; covering the whole face together with the neck usually takes 200-220 shots, and areas where ageing has advanced are treated with 3-4 overlapping passes. Repeat treatments are spaced at least three months apart — collagen remodelling unfolds over months, so shortening the interval gains nothing. → More about Sofwave

Conversely, if laxity has advanced to where the fascial layer needs to be tightened, this may not be the right device. Which of the two you need is judged by assessing skin thickness and fat volume together.

When it is not suitable

We do not treat if there is an open wound or active skin condition in the treatment area, in cases of severe cystic acne, if you have an implanted electronic device such as a pacemaker, or if you are pregnant, breastfeeding, or less than three months postpartum. If you have had filler or Botox, we proceed once 48 hours have passed.

Please also tell us in advance if you have used retinoids within the past two weeks, or if you take antiplatelet or anticoagulant medication.

In summary

In Sofwave's design, 1.5 mm is a choice rather than a ceiling. Seven parallel ultrasound beams heat the mid-dermis as a continuous layer, and the thermal effect stays within 0.5-2 mm, so it does not reach the fat below. It does not pull the fascia; it works on the thickness and firmness of the skin itself.

The published studies report improvement in wrinkles and laxity, but they should be read alongside their limited sample sizes and follow-up, and alongside the fact that the change in collagen density has not yet reached statistical significance. Results and duration vary between individuals, so which depth is right for you is something to confirm in consultation.

References

1. Suh DH et al. (2024). High-Intensity, Parallel Ultrasound Tightening of Facial Skin: Clinical and Pathologic Results. Journal of Cosmetic Dermatology. doi:10.1111/jocd.16670 (opens in a new window) · PMC11845918 (opens in a new window)
2. Hongcharu W et al. (2023). The efficacy and safety of the high-intensity parallel beam ultrasound device at the depth of 1.5 mm for skin tightening. Journal of Cosmetic Dermatology. doi:10.1111/jocd.15672 (opens in a new window)
3. Wang JV et al. (2023). Eyebrow Lifting From High-Intensity, High-Frequency, Parallel Ultrasound Beams. Dermatologic Surgery 49(7):718-720. doi:10.1097/DSS.0000000000003809 (opens in a new window)
4. Gold MH, Biron J (2024). Efficacy and safety of high-intensity, high-frequency, non-focused ultrasound parallel beams for facial skin laxity. Journal of Cosmetic Dermatology. doi:10.1111/jocd.16098 (opens in a new window)