A thin face doesn't rule out XERF if loose skin and fine lines are what bother you. It does mean the depth and energy have to be chosen area by area, and any spot that already looks hollow should be planned out of the deep treatment from the start.

If you're worried that a lifting treatment could leave you looking more sunken, say so at the very start of your consultation. Below, we walk through why thin faces heat differently, how XERF splits its depths, and how hollow areas are worked around.

Does XERF Heat a Thin Face Differently?

It can. Radiofrequency (RF) lifting works by creating heat in the dermis* and the layer beneath it to encourage tightening. Under the dermis sits the subcutaneous fat*, which supports the volume of your face.

*Dermis: the layer under the surface skin where collagen and elastic fibers sit.

*Subcutaneous fat: the fat layer under the dermis. Its thickness varies from person to person and from one part of the face to another.

One study tested 6.78 MHz radiofrequency in a computer model and in pork tissue, with fat layers from 2 to 8 mm thick. After treatment, tissue temperature reached 69°C with 2 mm of fat but only 45°C with 8 mm. In other words, the thinner the fat, the hotter the tissue got at the same setting. The researchers concluded that energy settings need to be adjusted to fat thickness.

Keep in mind this wasn't a study on human faces, so it isn't evidence that XERF suits thin faces better. What it does show is why one setting for the whole face doesn't make sense. Even within a single cheek, some spots have very little fat left and others still have some, a bit like ironing a garment that's thin in some places and thick in others.

What Makes XERF Different, and Why Can It Split Depths?

XERF is a monopolar RF device that fires two frequencies, 6.78 MHz and 2 MHz, one after the other within a single pulse. Published studies describe it as designed to deliver depth-dependent heating across the dermis and the layers below it.

In a multicenter study of 39 people at four US sites, treatment was delivered at three depths, shallow, middle, and deep, chosen by the target concern and the area of the face. For a thin face, that method matters more than the headline results. Being able to pick a different depth for each area is exactly what leaves room to plan around hollow spots.

Beautystone, a clinic in Seoul's Hapjeong area, added XERF in October 2026. For patients with a thin face whose main concerns are laxity or fine lines, both XERF and Thermage FLX are offered as options.

In What Order Are Depth and Energy Decided?

Knowing the order ahead of time helps you keep your own face at the center of the conversation. Here's how it typically goes:

• First, sort out whether your main concern is fine lines and texture, or sagging.

• Next, look area by area, such as the middle of the cheek, under the eyes, and just above the jawline, at how much fat is left, and mark any spot that already looks hollow.

• Then choose shallow, middle, or deep for each area.

• During treatment, the energy is adjusted based on how hot it feels to you and how your skin responds.

The published studies don't include a chart matching each concern to a depth. That's why the actual combination is decided by looking at your face in person, and it's also why results differ from person to person.

How Are Already-Hollow Areas Avoided?

When it comes to looking sunken, where the energy goes matters more than the device name. A study from Israel followed 16 women for three months after a single XERF session using 3D imaging. It found that volume shifted: it increased toward the outer face and decreased toward the center.

That was a small retrospective study with no comparison group, and the authors describe the findings as preliminary. Still, if the inner part of your cheeks is already thin, it's a point worth raising when the plan is made. Areas that already look hollow are either left out of the deep treatment range or treated at a shallower depth. How much change you see depends on your face shape and how much fat you have left.

How Many Sessions, and When Do Results Show?

In the 39-person study, the plan allowed up to three sessions spaced four weeks apart, but every participant finished after two. Results were assessed at 30 and 90 days, and doctors rated improvement at both points. In the 16-person study, a single session was followed for one and three months, and the eyebrows and upper eyelids rose gradually over that time in the 15 people measured.

Neither study had a comparison group, so treat these as early signals rather than promises. A practical approach is to see how you respond to the first session before deciding on a second.

XERF Side Effects and Safety: When Should You Call?

In the two studies above, side effects were mild and temporary, and none lasted. Because monopolar RF sends current through the body, tell your provider before treatment if any of these apply:

• You're pregnant or breastfeeding

• You have an implanted electronic medical device, such as a pacemaker

• You have metal or an implant in the treatment area

• The skin in the treatment area is inflamed

After treatment, watch which way things are heading. Contact the clinic that treated you right away if you notice a blister, pain that gets worse day by day, heat or swelling that hasn't changed after several days, a newly hollow-looking spot that wasn't there before, or skin that turns white or dark.

The Bottom Line: Agree on Where Deep Heat Can Go

Before you decide, ask which areas of your face can take deep heat and which should be left out. That one answer makes XERF much easier to compare with other options.

If you're considering XERF, a consultation is where you can find out what fits your face. When you reach out to Beautystone on WhatsApp, include front and side photos of your face, the spots that look hollow and bother you, and the names and dates of any lifting treatments you've had before. Pricing is listed on our price page.

Sources

• How fat thickness changes the way radiofrequency heat spreads — Biomed Mater Eng, 2026

• Dual-frequency radiofrequency at three depths, a 39-person multicenter study — Cureus, 2026

• 16 people followed with 3D imaging after one XERF session — Lasers Med Sci, 2026