What Is XERF? How It Works, Results and How Long It Lasts

Medically reviewed by Dr. Kang Kun Woo, Chief Doctor, Newstar Clinic (official XERF Key Doctor) · Last reviewed: November 11, 2026

"I keep seeing XERF everywhere. What is it, and does it actually work?" Since XERF arrived in the US, this is one of the questions we hear most from international patients. Newstar Clinic in Gangnam, Seoul has offered XERF since its early days in Korea, where the device was first launched. Here is what it does, how it feels and what to expect.

XERF at a glance

• Best for: loss of firmness, fine lines, a softening jawline or double chin, and dull skin texture

• How it works: dual-frequency RF (6.78 MHz + 2 MHz) at three depths

• Comfort: cooling with every shot; no numbing cream needed

• Downtime: little to none; you can fly home right after

• Results: some tightening on the day, building over two to three months

• How long it lasts: about six months to one year

What is XERF treatment?

XERF is a non-invasive radiofrequency (RF) lifting device made by Cynosure Lutronic and first launched in Korea in 2024. It received US FDA clearance in August 2025, and US searches for it have grown fast since. Each shot delivers two frequencies together: 6.78 MHz works on the collagen and elastin in the dermis, and 2 MHz reaches the deeper fat layer that affects the jawline and double chin. The doctor can treat at three depths, shallow, middle and deep, to match each area of the face.

Does XERF hurt? Why it feels more comfortable

For most RF devices, stronger energy means more heat and more discomfort. XERF is built around cooling: with every shot, cooling spray fires up to 12 times, so the moment the skin starts to get hot, it is cooled again. The device also reads your skin's resistance in real time to keep the energy even. That is why XERF is done without numbing cream. You may feel moments of heat, most often along the jawline, but most patients find it easy to tolerate.

Watch: Does XERF hurt? Listen for the cooling during a treatment by Chief Doctor Kang Kun Woo (Instagram)

When will I see XERF results?

Many people feel their skin is a little tighter on the same day. Most of the change comes over the next two to three months, as new collagen and elastin form. Before-and-after photos you see online are usually taken weeks after treatment, so plan ahead if you have an event.

How long does XERF last?

Results usually last about six months to one year. How long they last depends on your age, skin and lifestyle, and your doctor will suggest when to repeat it at your consultation.

Is there downtime after XERF?

There is little to no downtime. Some redness or warmth can appear and usually settles within hours, and you can wear makeup and go about your day afterwards. A full-face session takes under an hour.

XERF vs Ultherapy: what is the difference?

XERF uses radiofrequency to tighten several skin layers at once, while Ultherapy uses focused ultrasound to reach the deepest layer, the SMAS. XERF suits overall firmness and texture with little discomfort, and Ultherapy suits heavier sagging along the jawline and cheeks. For a full comparison with Thermage and Sofwave, see XERF vs Ultherapy vs Thermage vs Sofwave.

Who is XERF good for, and who should avoid it?

XERF suits people who found Thermage too uncomfortable, people with thinner skin who worry about hollow cheeks after lifting, and those with both loss of firmness and a softening jawline or double chin. Tell your doctor in advance if you are pregnant or breastfeeding, have an infection or inflammation in the area, or have metal implants or a pacemaker, as RF devices need a doctor's check first.

How is XERF priced in Seoul?

XERF is priced by the number of shots, with 300, 600 or 900 shots depending on the areas treated and your concern. Your doctor checks your face first and recommends the shot count, then we confirm the total including 10% VAT before treatment. At Newstar Clinic, everyone pays from the same price list, whatever their nationality.

How do I choose a clinic for XERF in Seoul?

Choose a XERF clinic by whether the device is genuine, who plans the treatment and whether the clinic can compare it with other lifting options.

• Genuine device: XERF is made by Cynosure Lutronic. Ask which device and how many shots are being used.

• Who plans it: a doctor should examine your face and set the depth and shot count. Dr. Kang Kun Woo, Chief Doctor at Newstar Clinic, is an official XERF Key Doctor and performs XERF himself.

• More than one option: Newstar Clinic also offers Ultherapy Prime, Thermage FLX and Sofwave, so the plan can match your concern rather than one device.

• Clear pricing: the total, including 10% VAT, should be confirmed before treatment.

Getting XERF on a trip to Seoul: what should I know?

• English support: an English-speaking coordinator stays with you from consultation to aftercare.

• Recovery and flying: with little downtime, you can carry on with your trip and fly home right after treatment.

• Booking: send a front and side photo of your face and your Seoul dates on WhatsApp. Your doctor confirms the final plan at the consultation.

• Where and when: 531 Gangnam-daero, Gangnam, Seoul, near Exit 4 of Nonhyeon Station (Shinbundang Line). Open weekdays 10:00–20:00 and Saturday 10:00–18:00, closed Sunday.

Before your XERF consultation

1. Decide your main concern: overall firmness, jawline and double chin, or fine lines and texture.

2. Send us a front and side photo of your face on WhatsApp.

3. Tell us if you have metal implants or a pacemaker.

4. Results build over two to three months, so book well before any event.

Frequently asked questions

Q. Is XERF a laser?

A. No. XERF is a radiofrequency (RF) device. It heats the skin with RF energy rather than light.

Q. Do I need numbing cream for XERF?

A. No. Cooling fires with every shot, so XERF is done without numbing cream. You may feel moments of heat, but most patients find it easy to tolerate.

Q. Can I fly after XERF?

A. Yes. There is little to no downtime, so you can fly home right after treatment.

Q. How many XERF sessions do I need?

A. Many people see a change after one session. Your doctor will suggest whether and when to repeat it based on your skin.

Q. Can I combine XERF with skin boosters?

A. Yes, XERF is often paired with skin boosters such as Rejuran for glow and skin quality. Your doctor decides the order and timing.

Treatment details and booking at Newstar Clinic: XERF.

Related reading: XERF vs Ultherapy vs Thermage vs Sofwave · Do Skin Boosters Hurt? Less Painful Options · What Is PDRN, PN and Rejuran?

Curious whether XERF suits you? Send us a photo of your face and your Seoul dates on WhatsApp.