Ultherapy Depths Explained: 1.5, 3.0 and 4.5 mm and What the 8 mm Screen Shows
The FDA 510(k) summary for K180623 lists the energy of a single Ulthera pulse at under 2 joules. The same filing places the device in Class II under 21 CFR 878.4590, and its common name pairs two functions: focused ultrasound for tissue heating and pulse-echo imaging. Marketing conversations around the device tend to run on shot counts and session length. The clearance paperwork runs on something narrower: the conditions that govern energy and depth.
A 2018 Filing That Changed One Sentence
K180623, cleared in May 2018, was not a new device. It was an expansion of indication language layered onto an existing one. The predicate was K134032 from 2013, and the summary states that the two devices share the same design and performance characteristics. What actually changed was a phrase appended after the submental and neck tissue lift indication, extending it to cover improvement in the lax tissue appearance of that area, plus a software revision from version 1382 to 1700.
The clinical support behind that expansion was an open-label trial. Of 70 subjects, 51 showed a lift-area improvement of at least 20 square millimeters, and among those 51, a blinded assessor rated 84.3 percent as improved. Reported adverse effects were mild and transient; the summary records no serious adverse events and no unanticipated device effects.
A 510(k) clearance certifies substantial equivalence to a predicate device, not a fresh efficacy claim. The cleared uses stop at three: eyebrow lift, lift of lax submental and neck tissue, and improvement of décolletage wrinkles. Nowhere in the document is there a recommended treatment dose or a retreatment interval. There is likewise no provision addressing severe sagging or facial fat loss.
What the 8-Millimeter Screen Is Cleared to Confirm
The DeepSEE transducer displays a real-time cross-section down to 8 millimeters beneath the skin surface. The summary assigns that imaging function exactly two jobs: confirming that the transducer is properly coupled to the skin, and confirming treatment depth so the beam avoids bone.
It is not cleared as a feature that enhances outcomes. Fire energy through poor coupling and heat concentrates at the surface; fire it where bone sits beneath the treatment plane and the risk is pain and tissue damage. The language in the filing is oriented toward avoidance, not performance.
A 2022 review comparing four ultrasound devices found that Ulthera was the only one with an imaging function at all. In the same comparison table, per-region line tracking, patient record-keeping, and stored imaging logs were all marked unsupported for the other three devices. That paper used Ulthera as its reference device, though, and its comparison set stops at four.
Under Two Joules, and the Coagulation Points They Form
Ulthera generates thermal coagulation points, or TCPs, in the dermis and fascia without touching the epidermis. The summary states that these points stay confined to a shallow band under 5 millimeters and that thermal coagulation does not continue past the focal point. The same section notes that epidermal cooling is not required. Tissue research describes these coagulation points as forming above 60 degrees Celsius.
Independent testing put Ulthera’s focal gain, the ratio of focal to surface acoustic pressure, between 62.2 and 139.49 depending on the transducer. Under the same conditions, the other three devices ranged from 20.9 to 72.9, and Ulthera’s beam was the shortest along the depth axis, at 0.75 to 1.64 millimeters.
Thermal management is where the gap widens further. After 30 minutes of continuous irradiation at maximum repetition rate, Ulthera’s transducer temperature rose by 0.8 to 1.1 degrees. One competing device’s cartridge reached 54.9 degrees and another reached 63.4 degrees, both above the 43-degree patient-contact-surface limit set by the test protocol, and one of the two never triggered an error control. Power draw for Ulthera stayed nearly flat, between 85.7 and 86.1 VA.
Labeled and measured values also diverged. The test compared each device’s stated frequency against a hydrophone measurement, and one device deviated from its labeled value by as much as 24.3 percent. Ulthera’s deviation ranged from negative 1.0 to 10.0 percent.
What Turned Up in Tissue at Ninety Days
A histology study irradiated minipig skin at three depths, 1.5, 3.0, and 4.5 millimeters. At day 14, the thermal coagulation points appeared as lesions roughly 500 by 200 micrometers, their long axis running perpendicular to the skin surface. No epidermal ablation or exfoliation was observed.
By day 90, fibroblast counts and mature collagen scores around the coagulation points had risen significantly. HSP47-positive fibroblasts, marking a chaperone protein that assists collagen synthesis and maturation, were seen clustering toward the coagulation points at the same time point.
The new finding in this study concerned elastin. Newly formed elastin in the coagulation-point area increased significantly from day 14 to day 90. The subjects, though, were Yucatan minipigs rather than humans, and the energy settings were fixed at two levels.
Where the Word Shot Never Appears
Neither the clearance summary nor the independent test tables use the word shot. The units that do appear are number of lines, lines per transducer, and point-to-point spacing. For Ulthera, that spacing splits into 1.1 millimeters and 1.5 millimeters depending on the transducer used.
Behind the count-based pricing sits a consumables structure. The summary lists the console and handpiece as reusable, the transducer as single-use, with a shelf life of 12 months. Quantity is a unit for counting consumables. It has never been entered into the record as a unit of effect.
Depth selection precedes any number. The 1.5-millimeter setting targets shallow dermis, 3.0 millimeters targets deep dermis, and 4.5 millimeters targets the SMAS and platysma, though where those layers actually sit shifts by treatment area and by person. This is also where a consensus paper’s list of complications to guard against belongs: burns, nerve paresis, bruising, and fat atrophy. Before a total shot count, the figures worth checking are which depth of transducer was used, how many, and whether there’s a record of the layer actually being confirmed on screen.
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Scope — This article explains devices and technology. It does not provide individual diagnosis or treatment advice.