"How is XERF different from other sagging treatments?"
"I'm starting to worry about sagging along my jawline, but the idea of surgery is intimidating..."
"I've tried HIFU before, but the pain was too intense to continue."
"I want to improve my nasolabial folds and marionette lines, but I can't afford any downtime."
Do any of these concerns about sagging treatments sound familiar?
Hello, this is Smart Skin Clinic, an aesthetic dermatology clinic.
In this article, we take a detailed, medically grounded look at XERF, a radiofrequency device drawing attention for sagging treatment — how it works, the effects you can expect, how it differs from other treatments, what the procedure involves, and what downtime to expect.
*If there's something specific you'd like to know, you can jump straight to it using the table of contents below.
Group Chief Director, Smart Skin Clinic Group
Ishii Kota
Graduated from Juntendo University School of Medicine
Worked at Tokyo Women's Medical University Hospital and affiliated facilities
Worked at a major aesthetic clinic in Tokyo
Board-certified specialist, Japan Surgical Society
Board-certified specialist, Japanese Society of Anti-Aging Medicine
XERF is a monopolar RF (radiofrequency) therapy device developed by the South Korean company LUTRONIC.
It received certification in 2024 from Korea's MFDS (Ministry of Food and Drug Safety), the Korean equivalent of Japan's Ministry of Health, Labour and Welfare.
The most distinctive feature of Zarf is its ability to deliver thermal energy “three-dimensionally” from the dermis to the subcutaneous fat layer.
As a result, it is expected to simultaneously address multiple skin concerns—such as a double chin, sagging jawline, nasolabial folds, and marionette lines—while improving skin firmness, radiance, and pore tightening.
Radiofrequency (RF) generates heat by causing water molecules in the skin tissue to vibrate.
The mechanism by which this heat improves sagging is as follows:
RF treatments are also categorized as "monopolar," "bipolar," or "multipolar" depending on the number of electrodes used, and XERF employs monopolar RF.
Monopolar RF is a method that passes high-frequency current between an “electrode applied to the treatment area” and an “electrode attached to the body (counter electrode),” forming a closed circuit within the body to heat the target area. Because the energy reaches a wide area, it is suitable for mild to moderate sagging.
[Types and Characteristics of RF]
| RF type | Monopolar RF | Bipolar RF | Multipolar RF | Microneedle RF |
| Frequency | 6.78MHz / 2MHz | 1 MHz | 1 MHz | 2 MHz |
| Benefits | Heat penetrates broadly and deeply | Treatment depth can be specified | Energy concentrates centrally | Treatment depth can be specified |
| Drawbacks | Treatment depth cannot be specified | Treatment depth is shallow | Treatment depth cannot be specified | Downtime occurs due to skin puncture |
| Effect | Tightening · Promoting Skin Regeneration | Contour correction | Contour correction | Promotes skin regeneration |
The second feature of ZAH is the world’s first technology capable of simultaneously emitting two different frequencies—“6.78 MHz” and “2 MHz”—.
Conventional RF devices (such as Thermage and Volnewmer) typically use a single 6.78MHz frequency.
Why combine two frequencies? The answer lies in controlling treatment depth.
[The Relationship Between Frequency and Depth]
By combining these two , thermal energy can be delivered in a "three-dimensional" manner from the superficial layers to the deeper layers.
As a result, it has become possible to simultaneously treat “deep sagging” and “skin texture improvement”—which were difficult to address with conventional RF treatments.
In a preclinical study comparing 6.78MHz and 2MHz radiofrequency (i.e., XERF) in pigs, 2MHz was found to warm deeper tissue more readily, while 6.78MHz acted more effectively along the skin's fibrous structure. Combining the two produced more pronounced changes in components such as the collagen fibers that support skin firmness, with no fat cell damage observed. (Preclinical study)
The third feature of Zarf is that it offers three different irradiation modes depending on the depth of the skin.
This enables "customized irradiation" tailored to each individual's skeletal structure, fat distribution, and type of sagging.
| Mode | Deep | Middle | Shallow |
| Frequency | 6.78MHz + 2MHz (dual frequency) | 6.78MHz | 6.78MHz |
| Target | Deep fat layer | Deep dermis to superficial fat layer | Superficial dermis |
| Effect | Fat Cell Volume Reduction Lifting Effect from Deep Within | Promotes the regeneration of collagen and elastin in the dermis for a natural lifting effect | Immediate improvement in skin quality |
| Indications | Double chin Severe sagging along the jawline Loose skin around the mouth | Nasolabial folds Marionette lines Gorgo lines Mild to moderate sagging | Fine lines Lack of firmness and radiance Enlarged pores Facial redness |
By combining the characteristics of monopolar RF with its three irradiation modes, XERF delivers a range of aesthetic benefits.
[Expected Effects]
A loose, sagging jawline makes the face look larger and can add years to your appearance.
The Deep mode's three-dimensional approach to the deep fat layer can be expected to tighten a jawline blurred by aging, define the V-line, and create a slimmer-looking face.
Many patients notice a sharper contour right after treatment.
Jowls beside the mouth and a double chin are mainly caused by fat accumulation. This is especially common from the late 30s onward, when a slower metabolism makes fat more likely to build up under the chin.
By concentrating heat in the deep fat layer, Deep mode can improve mild-to-moderate concerns around the chin and mouth without surgery.
Nasolabial folds and marionette lines tend to form in areas prone to sagging, involving not only the dermis but also the subcutaneous tissue and the ligaments that anchor the skin to it.
Applying thermal stimulation to the deep dermis promotes medium-to-long-term collagen remodeling, which can be expected to improve skin elasticity and reduce wrinkles and sagging.
What sets ZAHF apart from other high-frequency treatments is that it can improve skin texture at the same time as treating sagging skin.
Promoting collagen production in the superficial dermis supports skin turnover and circulation, leading to improved firmness, radiance, and texture.
Many patients notice their skin feels "tighter" or that "makeup goes on more smoothly" immediately after treatment.
The greatest appeal of Zarf is not only the “immediate results right after the treatment,” but also the fact that it provides “medium- to long-term effects resulting from collagen regeneration 1 to 3 months later.”
With regular maintenance treatments, you can offset age-related collagen loss and maintain youthful-looking skin over the long term.
RF treatment has the effect of tightening pores by stimulating collagen production around them .
In addition, the capillaries that have dilated due to thermal stimulation will constrict, which may help improve facial redness .
XERF is a treatment with minimal downtime, though depending on individual factors and the specifics of treatment, the following reactions may occur.
[General Downtime Guidelines]
These are temporary reactions that subside on their own, and most people can return to their normal daily activities on the same day as their treatment.
How you care for your skin after treatment affects how long the results last and the risk of side effects.
Please keep the following in mind.
Some people may think, “I’m concerned about sagging, but RF treatments are painful.”
It’s true that traditional Thermage treatments could be quite painful.
However, the pain from a Zarf is often described as “feeling like taking a warm shower”, and in most cases, anesthesia is not necessary.
Zaf significantly reduces pain through its patented "Wave Fit Pulse" technology.
Wave Fit Pulse is a technology that intermittently emits energy in the form of “waveform pulses.”
Specifically, by alternately switching between high and low power levels during treatment, it simultaneously achieves three effects: "delivering heat deep into the skin," "minimizing damage to the epidermis," and "reducing pain."
Furthermore, the Zarf handpiece is equipped with a powerful cooling system.
During treatment, by cooling the skin’s surface while emitting light, it “reduces the risk of burns,” “minimizes pain,” and “provides a comfortable treatment experience”.
Thanks to Wave Fit Pulse and the cooling system, XERF avoids the "pain that resonates in the bone" or intense discomfort sometimes associated with HIFU or Thermage.
| Immediate effect | Right after treatment to 2 weeks | Thanks to the immediate contraction of collagen fibers, you can feel the tightening effect right after the treatment. |
| Medium-to-long-term effect | 1 to 3 months later | Thanks to collagen regeneration, the effects peak 1 to 3 months later. |
| Duration of effect | 6 months to 1 year | – |
| Interval between sessions | Every 3 to 6 months | – |
XERF's effects appear in two stages: an "immediate effect" and a "medium-to-long-term effect."
Results can be felt after just one session, but regular maintenance allows the effect to be sustained over the long term.
Results vary from person to person.
Many people wonder, "Should I choose XERF or HIFU?" or "How is it different from Volnewmer or Thermage?"
Here, we take a closer look at how XERF compares with other major sagging treatments.
| Device | XERF | HIFU | Thermage | Volnewmer | Potenza |
| Energy / type | Monopolar RF (6.78MHz + 2MHz) | Ultrasound | Monopolar RF (6.78MHz) | Monopolar RF (6.78MHz) | Needle RF |
| Target | Dermis to Subcutaneous Fat ( surface heating) | SMAS layer (point heating) | Dermis to subcutaneous tissue | Dermis to superficial fat layer | Dermis |
| Main effects | Toning Fat Reduction Skin Texture Improvement | Lift-Up Firming | Tightening | Firming Skin Elasticity | Acne scars, pores, and skin quality improvement Improvement of sagging and fine lines |
| Pain | Minimal | Pain that resonates in the bone | Strong | Minimal | Pain as if being pricked by needles repeatedly A tingling sensation like an electric shock |
| Downtime | Almost none | A few days ・Redness ・Swelling ・Pain similar to muscle soreness | Almost none | Almost none | A few days to about a week ・Redness ・Swelling ・Bruising |
XERF is recommended for those with more fat who also want to improve skin quality, while HIFU is recommended for those who want a strong lift from the fascia.
While the Volnuma is also an excellent device, the Zarf has a wavelength of “2 MHz,” which allows it to target deeper layers (the subcutaneous fat layer) .
XERF retains the benefit of being a "pain-free RF treatment" while also meeting the need to tighten fat a little deeper.
Looking briefly at the history of RF (radiofrequency) treatment helps clarify these differences.
Potenza is well known as a "microneedle RF" device that inserts ultra-fine needles into the skin, like a shiatsu press, and delivers RF energy from the needle tips.
It uses frequencies of around 1 to 2MHz, but its approach differs fundamentally from XERF.
You can receive both “Sagging and Tightening Treatment” using ZAF and “Skin Texture Improvement” using various skin boosters on the same day .
Because they act on different layers of the skin and use different approaches, they don't cancel each other's effects out. In fact, combining them in a single visit reduces the burden of multiple clinic visits while delivering a greater synergistic effect than either treatment alone — a combination that also makes medical sense.
The most important thing to remember when performing both procedures on the same day is to always “perform the ZAF first, followed by the skin booster injection”. There is a medical basis for this.
Ingredients in skin boosters (such as non-cross-linked hyaluronic acid or polynucleotides) can potentially break down or lose structure when exposed to high heat. If the injection were performed first, XERF's powerful RF heat could damage these valuable active ingredients.
XERF's thermal action boosts blood flow in the dermis, temporarily increasing cellular metabolic activity. Injecting a skin booster into skin in this "activated, more receptive" state can help active ingredients reach the tissue more efficiently.
Combining XERF with a skin booster is not simply additive — it multiplies "heat-based tightening" with "formulation-based skin regeneration support."
Zarf’s multi-frequency monopolar RF delivers heat over a wide area from the dermis to the fat layer, powerfully tightening the “deep-layer laxity” that causes sagging. Meanwhile, the Skin Booster directly targets the area just beneath the epidermis through to the dermis, improving hydration, firmness, and fine lines. To use a building analogy, Zarf “reinforces the framework (laying the foundation),” while the Skin Booster simultaneously “renovates the wallpaper (improving texture)” .
XERF's thermal stimulation triggers the skin's wound-healing response, switching on collagen and elastin production. Injecting a skin booster on top of this delivers the "materials" (such as amino acids and hyaluronic acid) and "stimulation" needed for cellular remodeling directly to the tissue, accelerating the strengthening of the skin's foundation more efficiently.
To make the tightening effect last and maintain beautiful skin, it's important for the dermis's extracellular matrix — the environment that supports collagen and other structural components — to be in good condition. Applying a hyaluronic acid- or PN-based skin booster to skin that has just received XERF's heat reinforces proper hydration retention and a regenerative environment, guiding the skin toward a more three-dimensional, healthy state.
Even among skin boosters, each formulation has its own strengths and the specific changes it brings. Likewise, the results of XERF's RF treatment vary significantly depending on how much heat is delivered and at what depth.
Since opening, Smart Skin Clinic has offered a wide range of skin boosters — including Juvelook, Profhilo, Sunekos, and Rejuran — and has built deep expertise in improving skin quality through injection treatments.
With the addition of XERF, our next-generation RF device, we can now combine our greatest strengths at an even higher level: injection techniques that make the most of each formulation's properties, together with precise treatment planning for sagging devices.
Our physicians carefully assess each patient's bone structure, skin thickness, degree of sagging, and ideal skin quality, then propose a personalized treatment plan combining the optimal XERF treatment depth with the most suitable skin booster.
The number of shots for Zarf depends on the treatment area. The larger the treatment area, the more shots are required, and the longer the treatment takes. Simply select the area you'd like to treat, and the number of shots will be determined.
Since this is my first time, I’d like to try it out first.
200 shotsApprox. 30 minutes
Nasolabial Folds, Marionette Lines, and Blurred Facial Contours
300 shotsAbout 45 minutes
Sagging of the Entire Face
300 shotsAbout 45 minutes
Sagging of the Entire Face + Double Chin
400 shotsAbout 60 minutes
Sagging of the entire face + double chin + sagging neck
600 shotsAbout 75 minutes
Once you've decided on the number of shots, you can book directly from the price list below.
Special Discount Price Through September 30
During this period, all shot counts are available at a discounted price.
Please select a clinic to view prices.
200Shot
Treatment time: Approximately 30 minutes
For first-timers who want to give it a try
cheeks only
300Shot
Treatment time: approximately 45 minutes
For those concerned about nasolabial folds, marionette lines, or sagging of the entire face
Cheeks + Under the Chin or Full Face
400Shot
Treatment time: Approximately 60 minutes
For those concerned about sagging skin across the entire face and a double chin
Entire Face + Under the Chin
600Shot
Treatment time: Approximately 75 minutes
For those who want comprehensive care that addresses even sagging skin on the neck
Entire Face + Under the Chin + Neck
For those who can't decide among the four options above
On the day of your appointment, please tell us about your concerns. After the doctor assesses the condition of your skin and sagging, they will recommend the optimal number of shots and treatment plan, and proceed directly with the procedure.
There are no counselors, and there are no upsells.
Only the essentials, at prices that make it easy to keep using them. That’s Smart Essential.
The treatment lasts 60 minutes. The number of shots—ranging from 200 to 400—will be determined on the day of your appointment. Since the 600-shot treatment (including the neck) takes 75 minutes, please book directly from the 600-shot option above.
Important Information Before Making a Reservation
If you wish to change the number of shots on the day of the shoot,
we may not be able to accommodate your request.
The duration of a Zarf treatment varies depending on the number of shots. Since our clinic schedules appointments based on the number of shots, same-day changes can only be accommodated if there is an available slot. If you decide on the number of shots at the time of booking, we can guarantee your appointment.
You may find our prices to be higher than those at other clinics. There’s a clear reason for this: price.
The way to deliver high-quality products at low prices is actually quite simple.Minimize the time wasted by the provider down to every minute and second.It’s a fundamental principle of business, and there’s nothing particularly special about it. Our clinic simply makes sure to consistently follow these basic principles.
If a 30-minute treatment fits into a 60-minute time slot, the remaining 30 minutes go unused. That cost will inevitably be factored into the price somewhere. If the time slot and the treatment duration match, that cost doesn’t arise in the first place. The cost that wasn’t incurred can then be passed on directly to the customer in the form of a lower price.
Cutting back is a waste of administrative resources, not a reflection on the quality of care. And if we have enough time, staff will be able to calmly attend to each patient individually.Patients, staff, and the clinic. We’ve incorporated a model that benefits all three parties simultaneously into our pricing.
Deciding on the number of shots when making your reservation is part of that process. We would appreciate your cooperation.
* The 400-shot and 600-shot options take longer, so there is a last-appointment cutoff time.
Jimbocho Clinic: until 19:00 on weekdays / until 18:00 on weekends and holidays | Yokohama Clinic: until 18:00 every day
If you book after the above times, the treatment cannot be completed within business hours, so we may ask you to reschedule.
The 200-shot and 300-shot options are not subject to the above restrictions.
There is little concern about sunken cheeks; in fact, because the heat helps return sagging fat to its original position (repositioning it), this treatment can be expected to improve the appearance of sunken cheeks.
While the general consensus used to be to “avoid sunken areas,” recent evidence has shown that treating these areas directly is actually effective. At Smart Skin Clinic, we have incorporated these latest findings and perform effective treatments with the goal of improving sunken cheeks.
Some patients notice a change after just one session, but since XERF cannot stop new age-related changes from occurring, we recommend maintenance treatments roughly every 3 to 6 months to sustain the results. Individual results vary.
This treatment is performed without anesthesia.
Thanks to Wave Fit Pulse technology, discomfort is greatly reduced. The sensation is similar to a warm shower.
Yes, you can apply makeup immediately after the treatment.
You can easily book from your smartphone.
A smart, effortless check-in: just give your name and our clinic IT system completes reception right away.
During counseling, please feel free to share any concerns. Rest assured, there is no pushy sales.
After the electrode pads are attached, gel is applied to the treatment area and energy is delivered while checking in with you throughout. The output is adjusted according to your skin condition and pain tolerance. You will typically feel a gentle warming sensation during treatment, with little to no significant pain.
We will provide detailed instructions on how to care for the treated area and what to keep in mind in your daily life.
In addition, with a focus on prevention and maintenance, we recommend appropriate home care products—such as oral medications and skincare products—that can help alleviate your concerns.
| Treatment Time | Treatment time varies depending on the number of shots. 200 shots: approx. 45 minutes 300 shots: approx. 60 minutes 400 shots: approx. 75 minutes 600 shots: approx. 105 minutes *The above are estimates only. Actual time may vary depending on the situation. |
| Recommended Number & Frequency of Treatments | We recommend treatment at intervals of roughly 3 to 6 months. |
| Downtime | Little to none · mild redness or swelling |
| Treatment on the day of counseling | Available |
| Makeup | Possible immediately after treatment |
| Skincare | Possible right after the treatment |
| Shower | Normal activities possible the same day; bathing possible from the next day (avoid long baths on the day of treatment) |
| Pain | A sensation similar to standing under a warm shower |
*Results vary from person to person.
[Legal Notices]
XERF treatment involves the use of medications or medical devices not approved in Japan. These medications and devices are imported personally under the judgment of our clinic's physicians, in accordance with the required personal import procedures.
Please refer to this page for information on medications and similar items that require caution in personal importation.
Ministry of Health, Labour and Welfare, "Medications and Similar Items That Require Caution in Personal Importation."
XERF is a sagging treatment perfectly suited to modern lifestyles, offering an excellent balance of minimal pain, minimal downtime, and strong results.
If you'd like a treatment you can relax through without enduring pain, want to address fat around the mouth and chin at the same time, and also want firmer, more radiant skin —
we warmly invite you to book a free consultation.
We will recommend the treatment best suited to your individual facial structure.
Smart Skin Clinic, Chief Medical Director / Physician
Kota Ishii
We oversee treatment policies across the entire group, tailored to the skin condition of each individual patient. The content on this page has been reviewed and approved in line with our clinic's treatment policies.
Kota Ishii, our Chief Medical Director, shares our clinic's approach to patient care.
For Your Daily Care
For the days ahead,
skincare that nurtures your skin.
&DR.is a skincare brand born from the findings of cosmetic dermatology. Its first product, BAKU, is a skin-nurturing serum that focuses on gentleness, centered on the plant-derived skin-conditioning ingredient BAKUCHIOL. It can be used gently every day, both in the morning and at night.
Jimbocho Clinic
〒101-0054
3-16-1 Kanda Nishiki-cho, Chiyoda-ku, Tokyo, EX Kanda Nishiki-cho Building 8F (general reception) / 7F
Hours: Mon–Fri 11:00–20:00 / Sat & Sun 10:00–19:00
Yokohama Clinic
〒221-0835
TS Plaza Building 2F, 2-23-2 Tsuruya-cho, Kanagawa-ku, Yokohama-shi, Kanagawa
Hours: 10:00–19:00
Hatchobori Clinic
104-0032
2nd Floor, Tokyo NS Building, 2-29-4 Hatchobori, Chuo-ku, Tokyo
Hours: 10:00 a.m.–7:00 p.m. (Closed from 1:00 p.m. to 2:00 p.m.) / Closed: Mondays and Thursdays
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