If you have been researching lifting treatments in Seoul, you have probably hit the same wall as everyone else: one clinic tells you XERF, the next tells you Ultherapy, and neither explains why they disagree. The two get compared constantly.
They are not actually the same kind of treatment, and in a lot of Seoul clinics they are not treated as alternatives at all.
Here is what each one physically does, what the published evidence currently supports, and why “which one” is often the wrong question to bring into a consultation.
They use different physics, not different brands of the same thing
Ultherapy uses microfocused ultrasound. Sound energy is focused to a point at a set depth, and the tissue at that focal point heats enough to contract and trigger a healing response.
Because it is focused, it can bypass the surface and deposit energy at a specific plane — including the SMAS, the fibromuscular layer surgeons work with during a facelift.
XERF is monopolar radiofrequency, made by Cynosure Lutronic. It is not a laser, despite how often it is written that way. Radiofrequency heats tissue by passing current through it, so instead of one focal point it warms a volume of tissue.
XERF’s particular design runs two frequencies — 6.78 MHz and 2 MHz — which lets it distribute energy across shallow, middle and deeper planes rather than a single fixed depth. It launched in Korea in 2024 and received US FDA clearance for non-invasive skin tightening in August 2025 (Cynosure Lutronic).
That difference — focal point versus volume — is the whole reason the comparison keeps going in circles. They are not competing for the same job.
Where each one actually works
| Ultherapy | XERF | |
|---|---|---|
| Energy | Microfocused ultrasound | Monopolar radiofrequency, dual frequency |
| Delivery | Focal points at set depths | Volumetric heating across depths |
| Main target | Deeper support, including SMAS | Dermal tightening and skin quality |
| Sensation | Sharp, brief, at each point | Warm, spread out |
| Typical downtime | Minimal | Minimal |
| Clinical record | Established over many years | Newer platform, evidence still building |
What the evidence currently supports
Microfocused ultrasound has a reasonably long publication record. Histologic work has shown remodeling of collagen and elastin in treated skin (PMC11743342), and clinical evaluations in the lower face have been published, including a prospective trial of 103 adults (PubMed 24990884) and work on skin physiology and safety (PMC6336023).
Monopolar radiofrequency as a category has a long clinical history behind it. XERF is a newer platform within that category, cleared by Korea’s MFDS and by the US FDA, with published work to date including tissue studies on collagen and elastin remodeling after dual-frequency delivery.
As with any recently released device, the body of human data continues to build.
What that means in practice is simple enough: choose based on what your face needs, not on which device is newest. Both approaches have a place, and the settings and technique used on the day matter more than the badge on the machine.
When one of them alone makes sense
Not everyone needs both. Two rough patterns come up often in consultation.
- Sagging is the main complaint, skin quality is fine. When the jawline has lost definition and the issue is descent rather than texture, focused ultrasound at the deeper planes is usually where the conversation starts.
- Skin looks thin, crepey or lax, but the outline is holding. When the face has not really dropped but the skin reads loose and papery, volumetric radiofrequency across the dermis addresses what is actually bothering you.
Most people over about 35 are somewhere between those two descriptions, which is where the combination question starts.
Why Seoul clinics often run both — and how the timing works
If one device works at focal depth and the other warms a volume, they cover different ground, and pairing them is a layering decision rather than a package upsell.
At Relieve, XERF is used alongside Custom Ultherapy in the signature lifting protocol, with the doctor performing the treatment directly.
The eye area is where that control gets tested. In June 2026, Dr. Park Tae-oh performed a live periorbital XERF demonstration at Cynosure Lutronic Academy Korea, a clinician conference held under the theme “XERF: Full Face Custom Design RF” that reached roughly 1,400 attendees online and offline, as reported by the Korea Economic Daily.
Periorbital work is considered technically demanding in radiofrequency because the skin is thin and the treatment site sits close to the orbital rim.
The part almost nobody explains is sequence and spacing, and it matters more than the choice of device:
- Heat accumulation is the real constraint. Both treatments raise tissue temperature. Whether they can run in one session depends on how much of the same area each would cover and at what energy setting, which is why the answer changes person to person.
- Order is decided at consultation, not in advance. Skin thickness, current condition on the day, and how much time you have all change the plan.
- Collagen change is slow. Immediate tightening is not the result. Remodeling develops over the following weeks and months, so judging either treatment at day three means judging swelling.
If you are visiting Seoul on a short trip, this is worth raising at the start of the consultation rather than the end. What fits into a four-day visit is a different plan from what fits into a schedule with follow-up.
When XERF is not the right starting point
Tightening treatments assume there is something to tighten. If the underlying issue is lost volume — temples, cheeks, the area under the eyes — tightening alone can make a hollow face read as more hollow, not less. That is a common disappointment, and it is usually a sequencing error rather than a device failure.
In that situation the conversation usually starts with volume and skin quality first — a filler where structure is genuinely missing, or a regenerative injectable such as Juvelook Volume, Rejuran or Re2O where the skin itself is depleted — with energy-based tightening layered in afterwards.
Radiofrequency is also not suitable for everyone. It is generally avoided with a pacemaker or other implanted electronic device, with metal implants in the treatment area, during pregnancy or breastfeeding, over active infection or broken skin, and with uncontrolled inflammatory skin conditions. This is a consultation question, not something to settle online.
What to ask before you book
- Which device model, and is the handpiece an original manufacturer tip?
- Who performs the treatment — the doctor, or a technician?
- How many shots, over which areas, at what energy setting?
- If both treatments are proposed, are they in one session or spaced out, and why?
- What is realistic for my face, and what is not?
A clinic that answers the last one honestly is usually worth more than one that says yes to everything.
Common questions
Is XERF better than Thermage?
Both are monopolar radiofrequency. XERF’s dual-frequency design distributes energy across more than one depth, where Thermage FLX works differently in how it delivers and cools. There is no published head-to-head trial in humans establishing one as superior, so any ranking you read is a clinical opinion. We cover the older comparison in Ultherapy vs Thermage in Korea and Thermage FLX in Korea.
Does XERF melt facial fat?
Fat reduction is not the intended purpose, and preclinical work on the device reported no fat cell death. That said, anyone already concerned about a hollow face should raise it at consultation rather than assume.
How long do results last?
Reported ranges cluster around six to twelve months for radiofrequency tightening, and individual results vary a great deal with age, skin condition and how much energy was delivered. Claims of much longer durability are not currently supported by published human data.
Is XERF a laser?
No. It is radiofrequency. The phrase “XERF laser” is common online but describes a different technology.
Can I have both in one visit?
Sometimes, depending on the areas covered and the energy used. It is decided by looking at your skin on the day rather than planned from a website.
About this article
Written and medically reviewed by Dr. Park Tae-oh, director of Relieve Clinic Seoul (Apgujeong, Gangnam). Dr. Park performs consultation and treatment personally. He demonstrated periorbital radiofrequency technique using XERF at Cynosure Lutronic Academy Korea in June 2026, and the clinic has used the platform since its early availability in Korea. Reviewed August 2026.
This article is general information, not a diagnosis or a treatment recommendation. Suitability, settings and sequencing differ for every person and require an in-person consultation. Individual results vary.
Dr. Park Tae-oh is the founder and director of Relieve Clinic Seoul in Apgujeong, Gangnam, where he performs consultation and treatment personally. His work centers on reducing discomfort during aesthetic dermatology, drawing on more than 30,000 clinical cases. In June 2026 he demonstrated periorbital radiofrequency technique using XERF at Cynosure Lutronic Academy Korea.
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