Line Counts, Dual Handpieces, Prime
What "Done Well" Actually Means

Three-Line Summary

• Line count is a meaningful variable. What the studies show, though, is the trend when line counts rise within a consistent plan — not that the total alone decides the result. The total has to come with an account of which areas and depths it was divided across.
• Energy level is not a value to push higher but one matched to skin thickness, fat volume and pain tolerance. Where facial fat is sparse or cheek hollowing is a concern, we consider holding the line count and lowering the energy.
• So-called dual-handpiece treatment is mainly credited with saving time; the evidence for better results or greater safety is thin. Ulthera Prime improves imaging, speed and comfort, while the treatment depths and the working principle are unchanged.

What the Line Count Actually Counts

Ultherapy focuses high-intensity ultrasound onto a single point beneath the skin to create micro-coagulation points. Each time the transducer fires, those points form in a row, and what a consultation calls "one shot" usually means one such line. The difference between 300 and 500, then, is how many lines were placed on the face.

Once a line forms, the tissue contracts so that its two ends draw closer together, and the tissue response that follows continues in the same direction. Two lines pull harder than one and sit closer together, so at the same intensity, more lines does work in your favor. The physics behind this goes beyond the scope of this article, so we will leave it there.

What the Studies Show

Clinical studies have looked at the relationship between line count and degree of improvement. Populations and assessment methods differ, which limits direct comparison, but studies using more lines tend to report higher improvement rates.

A 2025 systematic review and meta-analysis of ultrasound lifting (MFU-V) (Amiri M., Aesthet Surg J, 2025) pooled 42 studies and reported that roughly 89% of patients showed cosmetic improvement on physician assessment. The key variables it identified for consistency of effect were an appropriate line count and its distribution across depths. Note that the number did not appear on its own — it appeared together with how the lines were divided by depth.

Why "How Many Lines" Is a Limited Question

Someone treating only the lower face and jawline and someone including the midface and temporal region need different totals. Even over the same area, distribution shifts with the degree of laxity, the size of the change being aimed for, and any previous treatment. The fact that the person next to you had 300 lines tells you nothing about the number your face needs.

Look a little closer and even 500 lines splits two ways. For someone whose main concern is laxity along the jawline and lower face, the lines go in densely through that stretch and the rest of the face is treated only enough to connect it. For someone whose contour has settled gently across the whole face, the same total is spread more widely. The same total at a different density changes where you feel the result. Concentrating lines where the change is wanted is the basic idea behind distribution.

So the thing worth asking in consultation is not the total but this: "Which areas will this number be divided across, and how?" If no answer comes back, the number is closer to a quote than a plan. If instead you hear "this many lines along the jawline, this many across the anterior cheek, this many toward the temple," the number has reasoning behind it.

Settled Before the Line Count — Where, and at What Depth

Some values are decided before the line count. Which transducer to use, how to split the lines between areas, and which direction to run them. Once those are set, the total line count is close to a figure that follows from them.

Transducer Choice and Proportional Split

Ultherapy transducers create coagulation points at different depths. Since lifting is the aim, it might seem enough to use only the transducer that reaches the deep supporting layer — but that is not how it works in practice.

• 4.5 mm transducer — reaches the deep supporting layer of the face. It is the backbone of laxity improvement, but it is not used on its own.
• 3.0 mm transducer — acts on the deep dermis. Even when the deep supporting layer sits at 4.5 mm, expert guidance has noted that combining 3.0 mm with 4.5 mm is preferable to 4.5 mm alone, both for results and for adverse effects.
• 1.5 mm transducer — acts superficially. Its value lies less in lifting than in indications around surface elasticity and pores.

The point is in what proportion, and over which areas, the two transducers are divided. Skin thickness and the depth of underlying structures differ across the face, so the same transducer delivers energy to a different layer depending on where it is placed. A split that suited the jawline can be excessive on the anterior cheek, and the reverse holds too.

Direction (Vector), Coupling and Pressure

Coagulation points form in a row and the tissue contracts along that row. Which direction the lines are laid therefore shapes the overall impression of the result. Lines placed without regard to the direction in which the face is descending can leave less visible change for the same number of lines.

How closely the transducer is coupled to the surface of the face, and how much pressure is applied, are also adjusted by area. Poor coupling means the energy does not form in the intended layer; pressing too hard can carry the effect into unintended layers where the tissue is thin. This is hard to quantify in a study, but it is part of what determines how well the treatment comes together.

Each Area Raises Different Considerations

The face is not one flat plane. Skin thickness, fat distribution and the depth of the structures beneath all vary from area to area, so even with the same transducer the checks differ.

With these checks done first, "how many lines" falls out naturally as the result of the plan. Reverse the order and fix the number first, and you can end up treating areas that did not need it in order to reach the total, or running short of density exactly where it was needed.

Why Facial Fat Volume Is Not the Criterion

You often hear that "you should not have Ultherapy if you have no facial fat." That is not quite right. The criterion is not how much fat there is but which layer the laxity is occurring in.

• Little facial fat, with laxity present — the fat layer can be identified on live imaging and the plan can work around it, centering on the deep supporting layer. Areas that already look hollow get fewer lines, and where useful a volume-restoring treatment is planned alongside.
• Plenty of facial fat — the fat layer as well as the deep supporting layer can be treated, which may make the change easier to perceive. That said, if reducing volume itself is the goal, an approach working on a different layer may fit better.

Rather than sorting people into eligible and ineligible by how much fat they have, the natural order is to look at where the laxity sits and what condition the deep supporting layer is in, then decide which layers to treat and which to avoid.

The Same 500 Lines Is Not the Same Treatment

In short, the order is this: confirm skin thickness and the position of the fat and deep supporting layers on live ultrasound imaging; take stock of the direction and degree of laxity and of any area where too much delivery would cause a problem; and only then set transducer, intensity, line count, direction and technique. Even at 500 lines, 500 placed through that sequence and 500 filled in without distinguishing areas are different treatments.

Why Energy Level Differs From Person to Person

"You need a higher level for a good result" and "the level just hurts and means nothing" circulate side by side. Look at the evidence and neither is easy to assert.

Where the effect of line count has been covered by several clinical studies, there is almost no research comparing energy levels head to head. A 2013 trade article cited internal manufacturer data noting that lowering the energy from Level 4 to Level 1 left the 90-day outcome unchanged while reducing pain by up to around 38%, and the recommended level was subsequently lowered from Level 4 to Level 2. The details of that data were never published, however, and no study has yet compared histological change across levels directly.

What Theory Predicts

Raising the energy does enlarge the coagulation point. But the benefit does not scale in proportion to that size, and a larger coagulation point raises the chance of the effect spreading beyond the intended position. A point that should have formed precisely ends up encroaching on the surrounding area.

The working principle is therefore simple: adjust the variables the research has established (line count and distribution) first, and match the energy to the individual. Rather than chasing results by pushing intensity in a less well-evidenced direction, it is more reasonable to refine the plan within what has been confirmed.

When We Raise It, and When We Lower It

As the table shows, energy is not "better the higher it goes" but a value matched differently to each person. Nor does the intensity of the pain confirm how well the treatment was done. If the pain is hard to bear during the session, please say so rather than enduring it. Adjusting the parameters is often the better choice.

On So-Called Dual-Handpiece Treatment

Using two handpieces at the same time — two operators working both sides of the face at once — to shorten the session is commonly called "two-hand" or "twin" Ultherapy in Korea. It comes up often in consultation, so here is where the evidence stands.

The Reasons Given, and What to Make of Them

• "You spend less time enduring the pain." If pain is the problem, adjusting the energy or reinforcing the anesthetic preparation comes first. Conceding precision to save time, when the pain is being accepted for the sake of the result, may put things in the wrong order.
• "Watching the screen does not matter much." Being able to confirm delivery position on live ultrasound imaging is what defines this device family. Proceeding without that check makes it a treatment that does not use that characteristic.
• "Output drops as you fire, so it is better to use the early shots from two units." If that premise held, the same aim could be met by working with one unit and switching to the other after a set number of lines. It does not lead to a reason they must be used simultaneously.

Where the Evidence Stands

In short, the evidence that the dual-handpiece approach is better for results or safety is not yet sufficient, and the advantages cited are mainly speed and time efficiency. Conversely, treating two places at once makes it correspondingly harder to match depth and direction at each of them in real time.

At ABLE Dermatology we work one-handed while watching the screen. The reason for choosing this device in the first place is to match depth and direction while confirming delivery position by eye. That said, technique is a choice that varies between clinics, and whatever the approach, whether you can be told why it is done that way is the point a patient can check.

How Ulthera Prime Differs From the Earlier System

The system at ABLE Dermatology is Ulthera Prime (Merz). Ultherapy was first developed in 2009 and received US FDA clearance that same year as an ultrasound lifting device; Merz acquired it in 2014 and has carried it forward since. Ulthera Prime is the next-generation model, launched in Korea in March 2025.

What Changed

Being able to see deeper structures on the image has increased the information available before and during treatment. The maximum depth at which energy is actually delivered, however, remains 4.5 mm as before. Seeing to 8 mm does not mean treating at 8 mm; the deeper view is used as a reference for placing delivery accurately within 4.5 mm.

What Stayed the Same

• Energy delivery depths — 1.5 mm, 3.0 mm and 4.5 mm, unchanged.
• Handpiece — the same handpiece is used.
• Working principle and mechanism of action — unchanged: thermal energy of around 60–70°C is delivered at those depths to create coagulation points and prompt the tissue's repair response.

So, to be straightforward about it, a change of device generation is not the kind of change that transforms the result. A wider, clearer image and a shorter session should work in the direction of delivering the same plan more consistently, and of reducing the chance of energy reaching an unintended position where skin is thick or a localised area is being treated. Understanding it as an improvement in consistency and safety margin rather than in magnitude of effect is closer to reality.

What a Wider Image Actually Changes

The situations where a wider field matters are fairly specific: thick skin and fat that make the deep supporting layer hard to locate, a structure that may have been altered by previous treatment or surgery, and a narrow area where delivery has to be concentrated. Under those conditions, the more that is visible, the easier it is to judge where to deliver.

The shorter session is better understood the same way. More than the time saving itself, the real benefit is being able to finish while holding the same plan, without posture and concentration drifting during the session. Spending less time enduring the pain also lightens the load from the patient's side.

In the end, what matters more than device generation is whether the screen is actually being watched during treatment, and whether what it shows feeds back into the plan. Even on the newest model, not watching the screen removes the reason for choosing this device.

Five Things Worth Checking Beforehand

Whether a treatment "went well" is usually judged months later rather than on the day. Most of the factors behind that verdict surface in the consultation beforehand.

• Is your face assessed seated first? Lying down changes the direction and degree of laxity. Where to concentrate and what to avoid can only be judged with you sitting up.
• Are the achievable and the difficult explained separately? Most post-treatment disappointment comes from a gap in expectations. It matters to hear in advance what Ultherapy can address and what will need a different method.
• Is the screen watched during treatment? Checking the live image is both a characteristic of this device and the process that creates a safety margin.
• Is there a reason behind the plan? There should be reasons for the proportion of 4.5 mm to 3.0 mm, for which areas the lines are concentrated in, and for the direction of delivery. If you have the treatment without sedation, you will feel the technique change from area to area.
• Is the balance between result and adverse effects explained? If, for example, an area of the cheek looks hollow but there is laxity too, the explanation should be able to cover reducing the number of lines in the hollow area, shifting distribution to where laxity is marked, and planning a volume-restoring treatment for the hollow area alongside.

Of the five, the one that most shapes satisfaction is the second — aligning expectations. Much of the disappointment after treatment comes not from anything going wrong but from a mismatch, present from the start, between the change the patient expected and the range of change the treatment can produce. Hearing beforehand how far the change can be expected to go, and which parts need a different approach, makes the judgment months later far clearer.

One more point: under sedation it is hard to follow the process yourself. Awake, you can feel the sensation and the technique change from area to area, which lets you check for yourself that it is proceeding according to the plan you were given. It is a trade-off between comfort and awareness, so decide in consultation which suits you.

Please Tell Us Beforehand If Any of These Apply

The adverse effects most often reported with Ultherapy are a temporary palpable band-like ridge, cheek hollowing, and nerve-related symptoms. The principles for preventing them are not complicated: confirm the layer on screen, couple the transducer properly to the surface of the face, and deliver accurately into the intended layer. On top of that, we establish each person's fat thickness, the position of the deep supporting layer, the course of the nerves and any existing cheek hollowing in advance, and adjust line count, energy, depth and direction accordingly.

Making those adjustments properly depends on some information from you in consultation. This is not a list to be alarmed by — it is a checklist for building an accurate plan.

• Recent weight change — if weight loss has left your face looking drawn, we adjust the number of lines over the cheeks.
• Areas that already look hollow — tell us if you have been told your cheeks look hollow, or if there is an area you are conscious of. We plan that area separately.
• Whether your facial fat is on the sparse side — with a thin fat layer, the same energy feels and behaves differently.
• History of fillers or collagen-stimulating injections — let us know when and where you had Juvelook Volume, GOURI, Sculptra, Radiesse, Re2O and the like, and we will adjust the sequence and the interval.
• Other recent energy-based treatments — if you have recently had Density, Onda, Olewave or similar, we plan the interval together.
• Any experience of altered sensation in the face, or past facial surgery or trauma — the structure may have changed, so we route delivery differently.
• A history of keloid or hypertrophic scarring
• Pregnancy or breastfeeding
• Active infection, open wounds or ongoing inflammatory acne in the treatment area — we reassess once it has settled.
• Pain tolerance, previous experience with anesthesia, and drug allergies
• A tendency to bruise easily, or current use of medication that affects this

None of these is a reason you cannot have the treatment — they are reasons the plan changes. The earlier you mention them, the more room there is to adjust.

Afterwards: What to Expect and What to Watch

Warmth, redness and mild swelling can appear immediately after treatment, and depending on the area, bruising or tenderness on pressure may linger. These tend to settle with time. Temporary altered sensation and burns near the mandible have rarely been reported.

The change itself builds gradually as the tissue response accumulates, rather than on the day. That is why the studies mentioned above assessed outcomes at 90 and 180 days. Checking over time is more accurate than judging in the mirror straight away.

Worth Observing During Recovery

• Sun protection — pigmentary responses linger more easily during recovery, so keep protection up.
• Avoid excessive heat — hold off on saunas, hot compresses and hot baths until redness and swelling have settled.
• Moisturising and barrier care — maintain with low-irritation products.
• Confirm the next appointment — settling the maintenance timing and the order of any combined treatments keeps the plan on track.

Please Contact Us If

• Pain does not ease over several days and instead worsens
• Sensation on one side stays dulled, or your expression continues to feel different from usual
• A firm, palpable area persists for a long time
• Swelling or redness lasts longer than expected

Not a One-and-Done Treatment

Laxity is not a state fixed at one point in time but a change that keeps progressing. So rather than treating it as something finished in a single session, reassessing at regular intervals and maintaining is the realistic view. The plan for the next session is set by the response to the last, so remembering which areas responded well and which fell short makes the next plan more accurate.

Laxity also often stems not only from a lax deep supporting layer but from volume loss or migration of fat as well. In that case, planning treatments that address a different layer in sequence is more natural than repeating ultrasound alone. What comes first and what comes later depends on your skin and your treatment history, so we decide it together in consultation.

In short, having Ultherapy done well is not a matter of getting a big number. It is having a treatment in which the line count, energy, depth and direction are planned around the structure of your own face. Consultation is where that plan is made, and the treatment is where it is kept. The number follows from it.

From Consultation to Treatment

A board-certified dermatologist examines you, identifies the layer behind the problem, sets the device and parameters, and then carries out the treatment personally. Treatment is not recommended to you by a consultant.

Number of sessions, intervals, maintenance timing and cost are all settled together before the first treatment.