Same Device, Different Results — Is It the Machine or How It's Used?

Summary in Three Lines

• A device name only tells you which machine was switched on. What to treat, which layer to target, how much energy to deliver, how many times to overlap and at what skin response to stop are decided by the person performing the treatment, and these settings (parameters) can make the same device a different treatment.
• In studies, too, results changed with the settings. With V-Beam, the settings that suited larger visible vessels and background redness were different; with Ulthera, the side given more energy and more treatment layers showed both greater tissue displacement and more pain. Conversely, there are examples where changing a setting kept the effect similar while reducing pain.
• Numbers such as shot counts, joules (J) and session counts show only part of the treatment dose. If an earlier treatment did not seem to work, it is worth checking the diagnosis, whether the device suited the problem, and the settings, number of sessions and intervals before ruling the device out.

What a Device Name Doesn't Tell You — Same Machine, Different Settings

A device name only tells you which machine was switched on that day. What it was used for, at what depth and how much energy went in are not part of the name. What people tend to remember afterward is usually the device name, the number of shots and whether it hurt. That is why, when we hear about an earlier treatment, we first ask how many sessions you had, at what intervals, and how your skin looked afterward, rather than starting with the device name: the name alone cannot tell us what treatment was delivered that day.

The person performing the treatment decides far more than that on the day: what to treat, which layer to target, how much energy to deliver at a time, how many times to overlap and at what skin response to stop. It is a little like an oven: the same oven produces very different dishes depending on the temperature, the time, the ingredients and when the dish comes out.

Broadly, there are two ways to use the same device. One repeats preset values in the same way for everyone; the other changes the values according to the skin and the lesion on the day. The wider the adjustment range a device allows, the bigger the difference between the two. At ABLE Dermatology, we set the values according to the condition of the skin on the day and its response during treatment.

Parameters — Values That Move Independently Within One Machine

Parameters are the adjustable settings on a machine, and even a single laser has several that move independently. A review in Lasers in Medical Science (Park et al., 2026) concluded that not only the wavelength but also the pulse duration, fluence and spot size need to be adjusted together in response to the skin reactions seen during treatment. In other words, the settings are matched to the skin's response rather than fired from memorized numbers.

RF microneedling, ultrasound and microwave devices add further settings such as needle depth, tip type, power (W) and time.

Laser Toning and Picosecond Lasers — Several Methods Under One Name

Toning Is a Method, Not a Machine

If pigmentation has not changed after several toning sessions, the first question is not how many sessions you had but what kind of toning it was. Toning shares only the principle of passing over the skin many times with a large spot at low fluence; the numbers within it vary.

The published studies show this too. A clinical study that treated 40 Polish women (Micek et al., 2022; no control group) used a 6–8 mm spot, a fluence of 1.7–3.2 J/cm² and 2–8 passes over 9 sessions. A single-institution study that followed 34 patients for 1 year (Gokalp et al., 2016) used a 6 mm spot and a fluence of 2.5 J/cm² over 6–10 sessions. Both are toning, but the spot size, fluence and number of sessions differ. In Korea, most toning is done at low fluence, so the overall approach tends to be broadly similar.

We first look at whether the pigment sits mainly in the epidermis or in the dermis, and set the parameters accordingly. A session may end with no visible irritation, or it may go as far as a slight flush of redness. Rather than fixing the values given in papers or by the device manufacturer, we adjust them while watching the skin's condition and response. The types of toning and the difference between nanosecond and picosecond lasers are covered separately in our article on nano and pico toning.

Picosecond Lasers — Different Treatments With One Machine

A "picosecond laser" is not the name of a treatment. It is a general term for machines that fire light in very short pulses measured in picoseconds (trillionths of a second). The same machine can deliver at least three treatments of quite different character.

• Pico toning — passing over a wide area many times with 1064 nm at low fluence
• Spot treatment — treating individual spots one at a time with 532 nm
• Pico fractional — splitting the light into fine beams with a fractional handpiece to work on skin texture

Afterward, all three tend to be remembered simply as "pico," but pico toning and spot treatment are different procedures. This is also why the quoted cost can differ even though it is the same picosecond laser.

The roles can also be divided within one session. In a pilot study in which 13 people enrolled and 10 completed (Leight-Dunn et al., 2022), solar lentigines were first treated spot by spot with the 532 nm non-fractionated handpiece, followed by full-face passes with the 1064 nm and 532 nm fractional handpieces. In other words, spot treatment and texture work were done separately, on the same day, with the same machine.

The tissue response also changes with the settings. In an experiment on excised micropig skin (Lee et al., 2019), the size and degree of the tissue reactions differed with the wavelength, the fluence and the way the beam was split. These are results seen in pig skin tissue, not in the human face.

What people often call "spots" can include solar lentigines, freckles, melasma and post-inflammatory hyperpigmentation. When the diagnosis differs, the wavelength and handpiece need to differ even with the same picosecond laser. That is why "I've had pico before" does not, on its own, tell us what treatment was actually delivered.

Potenza — A Shot Count Only Tells You How Many Times the Needles Went In

For example (the numbers here are an example for illustration), which counts as more treatment: 1,000 shots at a low setting, or 300 shots at an intensity and depth suited to that skin? The shot count alone cannot answer that. Dr. Jeong's view is that, in some cases, the latter produces a more meaningful response in the skin.

Potenza is an RF microneedling device that delivers radiofrequency energy into the dermis through needles, and the shot count only tells you how many times the needles went in. Even within one device there are many adjustable values, such as monopolar or bipolar mode, 1 MHz or 2 MHz, tip type and depth, the number of pulses, on time and power (W), and when these values change, what happens inside the skin changes as well.

In a tissue study that applied non-insulated RF microneedling to the skin of 3 pigs (Feng et al., 2023), the energy level mainly determined the extent of thermal damage, and the needle depth mainly determined the depth of the channels. If the intensity is lowered to reduce pain and redness and only the shot count is increased, the heat response each needle creates becomes smaller. The effect can then be lower than with fewer shots at an appropriate intensity. That is why, in the example above, the 300 shots were seen as the more meaningful treatment.

This does not mean that shot counts are meaningless. With the same tip, the same intensity and the same depth, more shots do mean more treatment. Looking at shot count alone, in our practice a full face usually takes around 200–300 shots. Some areas, such as the nose and the central cheeks where pores or scars are present, are treated with several overlapping passes (multi-pass), but even there we recommend no more than 3 passes on any one spot, because excessive treatment can instead cause side effects, in the same way that overdoing toning can cause hypopigmentation. To achieve an effect, what matters is an appropriate amount delivered with appropriate settings.

How depth and tips are set differently for pores and scars is described in detail in our article on why Potenza may not seem to work.

V-Beam — Different Settings for Acne Marks, Redness and Scars

Red marks left by acne, widespread redness and red scars can all be treated with V-Beam (a 595 nm pulsed dye laser, PDL), but not with the same settings. The combination of spot size, pulse duration (ms), fluence (J/cm²) and passes changes the size and depth of the vessels that are affected. V-Beam can be used in different ways by changing tips and adjusting settings, and we mainly use 7 mm and 10 mm spots.

Studies in Which Different Settings Gave Similar Results

Some studies found similar effects even with different settings. In a split-face study of 20 patients with rosacea (Wu et al., 2025), 7 mm and 10 mm spots, and in a randomized study of 80 patients who received a single treatment (Liu et al., 2026), 6 ms and 10 ms pulse durations reduced redness to a similar degree.

Does that mean the settings don't matter? In the spot-size study, the fluence was adjusted according to the skin's response immediately after treatment, so the finding is closer to saying that short-term results are similar when the same response is reached. Even within that, pain scores were lower with the 10 mm spot (3.95 with 10 mm, 4.85 with 7 mm), and swelling and bruising were more frequent with 6 ms. Both studies were in patients with rosacea, and follow-up was short.

When the Target Changes, the Suitable Setting Changes

In a split-face study of 9 patients assessed 3 weeks later (Iyer and Fitzpatrick, 2005), larger visible vessels decreased more on the side treated with 1 pass at a bruising (purpuric) fluence, while background redness decreased more on the side treated with 4 passes at a non-bruising (subpurpuric) fluence.

Scars are different again. In a study in which the chest surgery (sternotomy) scars of 19 patients were each divided into two parts and treated at random (Manuskiatti et al., 2007), a 0.45 ms pulse duration improved scar volume and pliability more than 40 ms, and redness was unrelated to pulse duration. Because the study was in hypertrophic scars and keloids, its results cannot be applied directly to acne scars.

So for redness, we separate visible vessels from background redness and treat them with two layered settings, using a larger spot that reaches deeper for widespread redness. For scars, we look at both the tissue response and the vessels, and for acne marks we start from baseline settings and adjust them to the color and depth. How a vascular laser is chosen for each type of redness is covered in our article on V-Beam for diffuse redness.

Ulthera and Onda — What Line Counts and Joules Don't Tell You

Ulthera — How Many Lines, and Where They Were Placed

Under the same conditions, a higher line (shot) count with Ulthera tends to work in its favor. But whether the conditions really were the same cannot be known from the count alone. Ulthera focuses ultrasound to a point and creates rows of small thermal coagulation points, with each transducer aimed at a set depth. How many lines were used with each transducer depth, how densely the lines were placed and where on the face they were concentrated can make the same count a different treatment.

In a split-face pilot study (Sasaki et al., 2017) of a single treatment at the marionette folds, the side given more energy through more lines and more treatment planes showed greater tissue displacement, higher elasticity measurements and higher pain scores. In a randomized study of 51 participants with blinded evaluators (Wood et al., 2024), both a standard placement and a placement tailored to each person's anatomy improved jawline laxity; the authors concluded that tailored placement helps get more out of the treatment for people with anatomical variations.

If you didn't notice an effect, the degree of laxity also needs to be considered. A systematic review of 16 studies (Contini et al., 2023; all in women) concluded that focused ultrasound was effective for mild to moderate laxity, and that results declined as laxity became more severe or body mass index (BMI) rose. It is less a matter of the device being weak than of whether the treatment suited that face.

Onda — Same Joules, Different Ways of Heating

Delivering 1 W for 1 second gives 1 joule (J). This is the unit meant when people speak of "tens of thousands of joules" with Onda, which heats beneath the skin with microwaves. The same number of joules can therefore be delivered briefly at high power or over a longer time at low power. Which handpiece was used, over how large an area and at what speed are not recorded in the joule count either.

Is higher power the answer, then? Recommendations from an international advisory board of the device's users (Hoffmann et al., 2024) advise starting at low power and raising it while monitoring the patient's tolerance, and heating evenly over a longer time with limited power rather than raising the temperature sharply in a short time. The skin surface temperature was not to exceed 40–41 °C. Because these recommendations concern body cellulite, localized fat and the area under the chin, they cannot be applied as they stand to the whole face, but they do make clear that turning the power up until it hurts is not a goal in itself.

The opposite side needs to be considered too. If the power is lowered further and further and the joule count is filled without even a sense of warmth, the treatment may be comfortable, but the temperature may not rise enough. Some protocols raise the temperature first at the start (pre-heating), but no direct comparison has been found showing an advantage for this approach. We aim to keep the heat at a level that feels hot but bearable for a set length of time.

Pain and Effect — More Pain Is Not the Goal

Pain is not a unit for measuring effect; it is one of the values to be managed during treatment. In the Ulthera study above (Sasaki et al., 2017), the side given more energy and more treatment layers had both a greater effect and more pain, while in the V-Beam study (Wu et al., 2025) the 10 mm spot gave an effect similar to the 7 mm spot with less pain. In other words, some treatments hurt because more energy was delivered, and in others a change of method achieved a similar effect with less pain.

So even a device known for causing little pain can hurt, depending on the settings and the area. Conversely, any device can be made comfortable by lowering the settings further and further. It is the latter that is the concern: if every value is lowered to reduce pain, the tissue response may fall short.

Pain can also feel different from one session to the next with the same device. In that case, before asking which session was the right treatment, it is worth checking whether the two sessions were actually the same treatment. What we aim for is to reduce unnecessary pain while still delivering the energy that is needed.

If an Earlier Treatment Didn't Work — What to Check Before Switching Devices

Sorting out why a treatment didn't work changes what comes next. The point is not to decide who was at fault; this is where the choice between switching devices and using the same device differently is made.

1. Was the diagnosis right? — If what seemed to be melasma also included solar lentigines, the method needs to differ even with the same laser.
2. Was it a problem the device handles well? — As with focused ultrasound (Ulthera) in a face with severe laxity, every device has areas where it is inherently less effective.
3. Were the settings overly cautious? — Settings lowered to reduce recovery time and pain are not bad in themselves. But more sessions are then needed, and overly cautious settings can produce a result with little irritation but also little change.
4. Were the number of sessions and the intervals sufficient? — Treatments that build up over time, such as toning or RF microneedling, are hard to judge after just one or two sessions.
5. Was it a condition that tends to recur or has inherent limits? — Some conditions, such as melasma, need ongoing care even after treatment.

It is fine if all you remember is the device name and the number of sessions. Just telling us how your skin looked right after the treatment (redness, crusting, bruising, swelling) and how many days it lasted gives a fair idea of how the treatment was delivered that day. If you have photos taken right after an earlier treatment, those can help too.

This does not mean the device doesn't matter. Whether the output is consistent, whether the tips and consumables are genuine and whether the device is maintained are the basics. But device names, shot counts and joules are simply numbers that are easy to compare; they do not tell you what the treatment actually was. Rather than setting a number first and then filling it, we decide where and how much to use after looking at the skin on the day. If a treatment is described to you as "customized," it is reasonable to ask how the settings are divided by area and what is being changed this time based on the last response.

Put simply, the skin responds not to a device name but to the energy actually delivered. If it is your first treatment, rather than asking about shot counts or joules, you can simply ask, "Where on my face will you use it, and how?"

Precautions and Limits of the Evidence

Even with the same settings, results and recovery can differ depending on skin type, the type and depth of the lesion, skin thickness and age.

Laser toning has been reported to cause hypopigmentation, post-inflammatory hyperpigmentation and recurrence. With pulsed dye lasers, swelling and purpura (bruising) have been reported; with RF microneedling, redness and swelling, temporary pain and, rarely, post-inflammatory hyperpigmentation. With focused ultrasound, rare cases of altered sensation, bruising and burns have been reported in addition to pain and temporary redness and swelling, and microwave treatments can cause temporary redness and a stinging sensation. If an unusual reaction persists, treatment should be stopped and you should see a doctor.

The sources cited in this article include reviews, a systematic review, randomized controlled trials, small clinical studies, animal tissue experiments and recommendations from a device users' advisory board. Study populations, devices and indications differ from study to study, and the settings reported in papers are the conditions of those studies, not recommended values. This article summarizes the research findings confirmed so far as general information and does not replace individual medical care.

References

1. Park S, Hyeon J, So H. Strategic selection of multi-parametric laser settings and clinical endpoints in dermatology: an engineering-to-clinical review. Lasers Med Sci. 2026;41(1):137.
2. Micek I, Pawlaczyk M, Kroma A, et al. Treatment of melasma with a low-fluence 1064 nm Q-switched Nd:YAG laser: laser toning in Caucasian women. Lasers Surg Med. 2022;54(3):366-373.
3. Gokalp H, Akkaya AD, Oram Y. Long-term results in low-fluence 1064-nm Q-switched Nd:YAG laser for melasma: is it effective? J Cosmet Dermatol. 2016;15(4):420-426.
4. Leight-Dunn H, Hadi A, Patel F, et al. The effect of a dual-wavelength 532 nm and 1064 nm picosecond-domain laser with a fractionated holographic optic on photoaging and patient age perception: a pilot study. J Cosmet Dermatol. 2022;21(1):320-326.
5. Lee HC, Childs J, Chung HJ, et al. Pattern analysis of 532- and 1,064-nm picosecond-domain laser-induced immediate tissue reactions in ex vivo pigmented micropig skin. Sci Rep. 2019;9(1):4186.
6. Feng J, Zhang L, Qi J, et al. Histological damage characteristics and quantitive analysis of porcine skin with non-insulated microneedle radiofrequency. Skin Res Technol. 2023;29(6):e13396.
7. Wu D, Zeng R, Ye J, et al. Spot size matters: enhancing rosacea treatment with pulsed-dye laser. Lasers Med Sci. 2025;40(1):172.
8. Liu T, Liu Y, Meng X, et al. Beyond efficacy: pulse duration is crucial for adverse events in pulsed dye laser therapy for rosacea. J Dermatolog Treat. 2026;37(1):2665064.
9. Iyer S, Fitzpatrick RE. Long-pulsed dye laser treatment for facial telangiectasias and erythema: evaluation of a single purpuric pass versus multiple subpurpuric passes. Dermatol Surg. 2005;31(8 Pt 1):898-903.
10. Manuskiatti W, Wanitphakdeedecha R, Fitzpatrick RE. Effect of pulse width of a 595-nm flashlamp-pumped pulsed dye laser on the treatment response of keloidal and hypertrophic sternotomy scars. Dermatol Surg. 2007;33(2):152-161.
11. Sasaki GH, Abelev N, Papadopoulos L. A split face study to determine the significance of adding increased energy and treatment levels at the marionette folds. Aesthet Surg J. 2017;37(8):947-960.
12. Wood E, Gonzalez A, Almukhtar R, et al. Comparing the safety and effectiveness of microfocused ultrasound: standard vs targeted tissue protocol in lifting and tightening the lower face and upper neck. J Drugs Dermatol. 2024;23(4):249-254.
13. Contini M, Hollander MHJ, Vissink A, et al. A systematic review of the efficacy of microfocused ultrasound for facial skin tightening. Int J Environ Res Public Health. 2023;20(2):1522.
14. Hoffmann K, Zappia E, Bonan P, et al. Microwave-energy-based device for the treatment of cellulite and localized adiposity: recommendations of the "Onda Coolwaves" International Advisory Board. Bioengineering (Basel). 2024;11(12):1249.

From Consultation Through Treatment

A board-certified dermatologist examines you directly, identifies which layer the cause sits in, sets the device and the parameters, and then carries out the procedure as the same physician. This is not a structure in which a consultant sells the treatment.

The number of sessions, the intervals, the maintenance point and the cost are agreed together before the first session.

Related care: Potenza RF Microneedling in Seoul · V-Beam Laser Redness Treatment in Seoul