What is XERF? — The device, its regulatory class, and what it does and does not do
You have probably seen the name XERF in advertising. But when someone asks in the consultation room, “What exactly is XERF?”, the answer turns out to be long. We need to explain how it creates heat, under which category it is approved, and what that approval does and does not mean. This article introduces XERF as a device.
The short answer
XERF is a monopolar radiofrequency device made by Lutronic (now Cynosure Lutronic) that creates heat inside the skin with current at two frequencies, 6.78 MHz and 2 MHz. In Korea it is classified as a general-purpose electrosurgical unit; the indication under the US FDA 510(k) (K251327) is electrocoagulation and haemostasis, and no clinical trials were submitted. There are three human studies for lifting, none with a control group. It is neither a laser nor focused ultrasound, so it is not a device that treats pigment or deep volume directly. Miso Clinic (4F Bombom Building, 125 Dongdeok-ro, Jung-gu, Daegu, South Korea; +82-53-428-2700) is a XERF ambassador selected by the manufacturer, and we explain alongside this that the selection is not an assurance of results.
What kind of device is XERF?
XERF is a monopolar radiofrequency device. Radiofrequency current flows between the effector (tip) placed on the skin and a pad attached to the body, and heat is produced as the tissue resists the current. It is neither a device that fires light like a laser nor one that concentrates ultrasound at a point like Ulthera.
| Item | Detail | Source |
|---|---|---|
| Manufacturer | Lutronic (now Cynosure Lutronic) | Manufacturer published data |
| Energy | Monopolar radiofrequency | Manufacturer published data |
| Frequency | 6.78 MHz + 2 MHz (the manufacturer calls it “dual monopolar”) | Manufacturer published data |
| Cooling | ICD gas cooling | Manufacturer published data alone — no independent verification found |
| Effectors | i05 · i10 · E40 · E60, single-use | Manufacturer published data |
Where each of the two frequencies heats is set out separately in How XERF RF works: the two frequencies.
Under which category is XERF approved?
This is where misunderstandings are common. In Korea, XERF is classified as a general-purpose electrosurgical unit. The “General-purpose electrosurgical unit combination-2024-16-054” seen on promotional material is not an approval number but a medical advertising pre-screening marking.
| Category | Detail | How to read it |
|---|---|---|
| Korean device classification | General-purpose electrosurgical unit | A category for devices that produce heat in tissue with electric current |
| Advertising pre-screening | General-purpose electrosurgical unit combination-2024-16-054 | A marking for screening of advertising wording, not an approval number |
| US FDA 510(k) | K251327 (2025-08-11) | Indication electrocoagulation and haemostasis; no clinical trials submitted |
In other words, it is not a device whose public approval documents state a “lifting” effect. What we can know about lifting comes from the three human studies below. How an approval number differs from an advertising screening number is set out separately in the references.
How many studies have looked at XERF for lifting?
The studies that have used XERF on people for lifting number three as far as we can find, and none of them has a control group.
| Study | Subjects | Sessions · follow-up | Main findings |
|---|---|---|---|
| Hwang 2025 | 20 women (aged 28–63, Fitzpatrick III · IV) | 1 session · 12 weeks | Blinded assessors identified the photographs 80% of the time, mean GAIS 2.75/4, satisfaction 7.84/10 |
| Weiss 2026 | 39 people (manufacturer support) | 2 sessions · 90 days | E60 alone, improvement 84.6% at 30 days → 92.3% at 90 days |
| Erlich 2026 | Retrospective, 16 people | 1 session · 3 months | E60 · E10 · E5 combination, lower face 24–36 kJ |
The longest follow-up in the three studies is about 3 months (12 weeks · 90 days). There are no data yet for a longer period. A study without a control group cannot fully separate whether “it got better” is due to the treatment, or to time or expectation.
What can XERF do, and what can it not do?
The heat of radiofrequency warms tissue and aims for collagen contraction and renewal. So what it can and cannot do is fairly clear.
| Concern | Role of XERF | Other approaches |
|---|---|---|
| Skin texture · loss of firmness | The main thing we consider it for | Consider together with boosters |
| Mild to moderate sagging | Considered | If deep, consider adding a thread lift |
| Hollow cheeks · temples | Heat does not create volume | Fillers |
| Melasma · pigmentation | Not addressed | Miso Clinic does not have a melasma laser |
| Sagging deep enough that the skin folds | Beyond the non-invasive range | Surgical consultation |
Miso Clinic does not put XERF first for a face where hollowing is the main concern (clinical judgement). Tightening a hollow face with heat can make it look more hollow. Which skin it suits continues in Which skin types suit XERF?.
What does XERF ambassador mean?
Miso Clinic is a XERF ambassador selected by the XERF manufacturer, Cynosure Lutronic. The certificate hangs in the clinic.
| Category | Detail |
|---|---|
| What it means | The fact that the manufacturer recognised this clinic’s adoption of XERF and its treatment experience, and selected it |
| What it means | That the clinic has all four effectors (i05 · i10 · E40 · E60) and chooses among them by area |
| What it does not mean | A national qualification · a society certification |
| What it does not mean | An assurance of treatment results, or that the clinic is better than other clinics |
So we describe the ambassador role solely as “a fact of selection by the manufacturer”. Photographs of the certificate and the fuller story are in XERF ambassador in Daegu: i05 for the eyes.
What should I ask in a XERF consultation?
XERF becomes a different treatment depending on the effector set-up, the shot count and the number of sessions. Asking the following in consultation will show you the design.
- Which effector (i05, i10, E40, E60) will be used on which area?
- How many shots per effector? — a shot count cannot be compared unless it is written together with the tip set-up
- Is my concern sagging, or hollowing?
- When will the result be looked at again? — Miso Clinic looks again at around 3 months (clinical judgement)
- How is pain managed?
The order of a consultation is set out in XERF: how the evidence has changed, and side effects and precautions in XERF side effects and precautions. The map of all our XERF columns is XERF lifting in Daegu: which skin it suits.
What is XERF: frequently asked questions
What kind of device is XERF?
A monopolar radiofrequency device made by Lutronic (now Cynosure Lutronic). It creates heat inside the skin with current at two frequencies, 6.78 MHz and 2 MHz.
Is XERF approved as a lifting device?
In Korea it is classified as a general-purpose electrosurgical unit, and the indication under US 510(k) K251327 is electrocoagulation and haemostasis (no clinical trials submitted). For lifting, there are three human studies without a control group.
Is “General-purpose electrosurgical unit combination-2024-16-054” an approval number?
No. It is a medical advertising pre-screening marking. Approval and advertising screening are different procedures.
Can XERF improve melasma or hollow cheeks?
XERF is not a device for treating pigment, and heat does not create volume. For hollow cheeks we consider fillers first (clinical judgement).
Is XERF ambassador a national qualification?
No. It is a selection by the manufacturer Cynosure Lutronic. It is not a national qualification, a society certification or an assurance of effect, and it does not mean the clinic is better than other clinics.
Where can I have a XERF consultation in Daegu?
Miso Clinic is at 4F Bombom Building, 125 Dongdeok-ro, Jung-gu, Daegu, in front of Exit 1 of Kyungpook National University Hospital Station. +82-53-428-2700. Weekdays 11:00–19:00, Saturdays 10:00–16:00 (no lunch break); closed Sundays and public holidays.
Read next
Product pages
Related: XERF product page
Who wrote this
Written and reviewed by Lee Chi-Hak, MD, director of Miso Clinic, Daegu. The treatment standards and injection design set out here are the ones we use in practice.
| Medical director | Lee Chi-Hak, MD |
|---|---|
| Address | 4F Bombom Building, 125 Dongdeok-ro, Jung-gu, Daegu, South Korea · Exit 1, Kyungpook National University Hospital Station |
| Phone | +82-53-428-2700 |
| Hours | Weekdays 11:00–19:00 (lunch 13:00–14:00) / Saturday 10:00–16:00 (no lunch break) / Closed Sundays and public holidays |
| Columns | All clinical columns |
| Reference library | All booster and device references |
References
- XERF specifications — Lutronic published data: monopolar, 6.78 MHz + 2 MHz, handpieces i05 (5×10 mm · 400 shots) · i10 (10×10 mm · 300 shots) · E40 (20×20 mm · 600 shots) · E60 (20×30 mm · 600 shots). Classified in Korea as a general-purpose electrosurgical unit; advertising marking “General-purpose electrosurgical unit combination-2024-16-054”.
- XERF US 510(k) — FDA K251327 (2025-08-11). The indication is electrocoagulation and haemostasis, and no clinical tests were submitted. In Korea the device is classified as a general-purpose electrosurgical unit.
- Licence numbers and advertising pre-screening numbers — a Korean MFDS medical device licence and a medical advertising pre-screening are two different procedures. Example: “General-purpose electrosurgical unit combination-2024-16-054” on XERF promotional material is an advertising pre-screening marking.
- Three XERF human studies — Hwang JK, Medical Lasers 2025;14(1):23–30 (20 subjects · one session · 12 weeks) · Weiss RA et al., Cureus 2026;18(3):e104546, PMID 41930066 (39 subjects · two sessions · 90 days, manufacturer support) · Erlich G et al., Lasers Med Sci 2026;41(1), PMID 42611100 (retrospective, 16 subjects · one session · 3 months). None of the three has a control group.
- XERF cooling method — the description of ICD gas cooling in Lutronic’s published material. The manufacturer’s published material is the sole source, and we could not find independently verified data.
- XERF ambassador — the manufacturer Cynosure Lutronic selected Miso Clinic as a XERF ambassador (certificate in the clinic). It is a selection by the manufacturer; it is not a national qualification, a society certification or an assurance of treatment results, and it does not mean the clinic is better than other clinics.
- Medical advertising law — Medical Service Act of Korea, Article 56(2), which prohibits testimonial advertising, comparison with other clinics, superlative claims and advertising that guarantees or implies a guaranteed treatment effect.
- Miso Clinic practice guidance — indication criteria, site-by-site design, and the explanation and consent procedure. This is the source for every sentence marked as clinical judgement.
Everything in this column is general information and does not replace medical diagnosis or treatment. Effects and side effects vary with individual skin condition, age and underlying illness, and the same result is not guaranteed for everyone. Any decision to proceed should be made in an in-person consultation with a physician.
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