Two Frequencies Are Not a Facelift

A second frequency is a feature. It is not a second result.

The Kakao reply comes back fast. "Xerf 600 shots." Your Thermage quote also said 600. Same energy family, same number, so it must be the same thing at a new price. It is not. One machine runs on one frequency, the other on two, and each counts pulses from its own tip over whatever area the clinic decides.

If you remember one test, remember this. Ask which tip, how many shots at which depth setting, on which part of your face. If nobody can name the depth setting, the two frequencies are a word on a poster, not a plan for your jaw.

What is Xerf, and how is it different from Thermage?

Xerf is monopolar radiofrequency. A tip sits on your skin, a return pad sits on your back, and current runs between them. The US filing lists two frequencies, 2 MHz and 6.78 MHz.¹ The maker is Cynosure Lutronic, formed when Korea's Lutronic and the US firm Cynosure combined. It launched in Korea in May 2024. The MFDS approved it on January 3, 2024, under permit 제허 24-6 호, as a general-purpose electrosurgical unit for radiofrequency tissue coagulation.^{2, 3, 19, 20}

The second frequency is the difference. There are three depths. Shallow and middle use 6.78 MHz alone. Deep adds 2 MHz.⁴ Cryogen gas cools the tip, and a sensor cuts the output if the skin surface passes 43°C.⁴ Thermage FLX runs on 6.78 MHz only,⁵ and the Xerf filing named Thermage FLX as the device it is equivalent to.¹

So what does 2 MHz add? In a computer model and in pig skin, it spread heat broader and deeper into the fat layer, and the two together produced a pronounced reaction where dermis meets fat.⁶ The maker is among the authors' affiliations. Deeper heat in a pig is a reason to study people. It is not a deeper lift on you.

The tips matter more than the brochure. They are single-use and come in four sizes,² and two small tips for narrow, curved areas arrived in August 2026.⁷ Sales passed 3,000 machines in 18 countries by September 2026.⁷ That explains the menus, not your face.

Still choosing between ultrasound and radiofrequency? Our Ultherapy and Thermage guide covers that split.

Does Xerf work, and who is it for?

Honestly, it is early. We found three human studies of Xerf with outcomes, 75 people in total. None had a control group. None followed anyone past about three months.

The Korean study treated 20 women aged 28 to 63, once. At 12 weeks, two blinded doctors picked the after photo 80% of the time and scored the change at 2.75 out of 4. Pain was 4 or 5 out of 10 with no numbing. It looked back at one practice the paper calls affiliated with the maker.⁴

The US study treated 39 adults at four sites, twice, four weeks apart. At 90 days investigators rated 92.3% as improved, and no side effect lasted. The maker supplied the machines and a research grant.¹³

The third reviewed 16 women after one session and measured a rise in brow and upper-lid position at three months. The authors call it preliminary, and the first author trains doctors for the maker.¹⁴

We found no published trial of Xerf against Thermage, Ultherapy or Sofwave (PubMed search, October 2026). For radiofrequency in general, a systematic review found measurable improvement in laxity and mostly minor, short-lived complications, with major ones more common on monopolar devices.¹⁵

Small, short and mostly sponsored. That is not nothing. It is not proof either.

So who is it for? Early softening along the jaw. A brow a little lower than it was. Skin that looks tired more than loose.

A jowl that hangs over the jawline is a different conversation. Heat tightens. It does not move tissue back up. Surgery repositions it, and the SMAS and deep plane facelift guide shows how; threads, which pull instead of heat, have a guide of their own. For the wider Seoul menu, start with our overview of popular skin treatments.

How much does Xerf cost in Korea?

No neutral, dated source for Seoul Xerf prices turned up in our search. Clinic pages and event apps are sellers, so this page prints no won or dollar figure. What you can check instead is what a Xerf quote has to say before its number means anything.

The tip comes first. A large tip on the cheeks and a small tip around the eyes are different work.⁷ Ask whether the single-use tip is new and opened in front of you.²

Then the count. A shot is one pulse from that tip, and a count means something only next to the tip size and a map of where it goes. "600 shots" on Xerf and "600 shots" on Thermage FLX are different pulses from different tips on different machines.

Then the depth. Shallow, middle or deep, and how many shots at each. Deep is the only setting that uses the second frequency.⁴ A quote that never says deep is a single-frequency treatment with a new name.

A new device often arrives with an introductory tile. A lower number can mean fewer shots, a smaller tip, one depth only, or one area instead of the full face. That is not a scam. It is a different appointment. A quote from home in sessions and a Seoul quote in shots compare only once both are itemized.

Then VAT, the line people forget. Korea's 10% refund for foreign visitors' cosmetic procedures covered treatment received by 31 December 2025, and it was not extended.^{16, 17} Ask whether the won figure includes it.

What the appointment and the week look like

The maker says Xerf usually needs no numbing.² The Korean study is more useful: pain at 4 or 5 out of 10 with none.⁴

You lie down with a pad on your back. That is the return electrode, part of how monopolar radiofrequency works,¹ and it is why metal and electronics matter. The Korean study excluded people with a pacemaker, a defibrillator, metal pins or a prosthetic joint.⁴ Mention any implant before the day, not on the bed.

Afterward, expect redness and some swelling, which in the published studies did not last.^{4, 13} Our aftercare guide covers sun, makeup and flying days after a skin device.

The message that books the right Xerf

Send this before any deposit:

For how to shortlist the clinic itself, see our guide to Seoul skin clinics for foreigners.

Two frequencies on the machine. One written plan for your face. Get the second before you pay for the first.