Density and XERF side effects and burns — how rare they are, and what to watch for when
The purpose of radiofrequency lifting is to heat tissue, and that purpose is also the source of its risk. The accurate way to describe Density and XERF side effects is not “there are none” but “they are rare, and they appear at predictable times”.
The short answer
With non-invasive RF lifting such as Density and XERF, the common reactions are redness, a feeling of heat and mild swelling for a day or two, and most settle within the day or a few days. Rare side effects appear in two windows — blistering and burns from right after treatment to 72 hours, and fat atrophy (cheek hollowing) at one to four months (mean two months), reported at about 4 per 10,000 treatments. No serious adverse events were reported in the human data for Density (16 people) or XERF (75 people), but with such small denominators this should be read as “the numbers are still small”, not as “rare”.
What are the common reactions and rare side effects of Density and XERF?
| Reaction | Frequency | When it appears · how long |
|---|---|---|
| Redness and heat after RF lifting (Density, XERF) | Common — periorbital study of 86 people: 36.0% immediately, 16.7% at 72 hours, 3.9% at one month | Right after · a few hours to a day |
| Mild swelling after RF lifting (Density, XERF) | Common | A day or two |
| Blistering and burns after RF lifting (Density, XERF) | Rare — with the older high-energy technique, second-degree burns in 21 of 5,858 treatments (0.36%) | Right after to 72 hours |
| Fat atrophy (cheek hollowing) after RF lifting (Density, XERF) | Rare — about 4 per 10,000 treatments | 1–4 months, mean 2 months |
| Altered sensation after RF lifting (Density, XERF) | Rare | Usually temporary |
The 0.36% figure comes from a 2002 device using a high-energy single-pass technique and is not the current incidence for Density or XERF. No data set on Density or XERF is large enough to calculate a burn rate for either device.
How do Density and XERF reduce the risk of burns?
What causes an RF burn with devices such as Density and XERF is not the temperature itself but where the heat builds up. Heat is needed in the dermis and below, but the current passes through the epidermis to get there, and if the epidermis heats up too, the result is a burn.
| Device | Epidermal cooling | Output correction · monitoring |
|---|---|---|
| Density (Jeisys Medical) | Five-level gas cooling | RIC automatic impedance adjustment, real-time skin temperature display (surface temperature) |
| XERF (Lutronic) | Cryogen spray | Impedance feedback; surface temperature kept below 43 °C in porcine preclinical testing |
Cooling and temperature monitoring on Density and XERF reduce risk; they do not remove it. Heat you cannot bear during Density or XERF is not something to endure but a safety signal to report straight away. Heavy anaesthesia has been noted to block this pain feedback, so Miso Clinic does not make anaesthesia deeper than needed.
What must you tell us before Density or XERF?
- A pacemaker, defibrillator or other implanted electrical device — with monopolar RF such as Density and XERF the current passes through the body, so as a rule we do not treat
- Metal implants in the treatment area — we avoid the area or adjust Density or XERF settings
- Filler, threads or non-dissolvable materials (PCL · PLLA · CaHA) in the treatment area — the effect of heat on them has not been established, so we adjust the area or timing
- Pregnancy, infection or active skin disease in the treatment area
- Recent strong heat treatment on the same area — Density or XERF waits until you have recovered
For isotretinoin (acne medication), a consensus paper reviewing about 27 studies concluded that no waiting period is needed before procedures including RF such as Density and XERF. If you are taking it, just mention it at consultation.
Contact us straight away with these symptoms after Density or XERF
- 0–72 hoursBlistering, oozing or pain that keeps getting worseThese can be signs of a burn after Density or XERF. Do not wait; contact us straight away.
- A few daysRedness that spreads instead of fading, heat getting worseInfection or another reaction after Density or XERF needs to be checked.
- 1–4 monthsOne spot looks sunkenThis may be fat atrophy after Density or XERF. Left alone it can deepen, so early review is needed.
- Any timeNumbness or tingling that lastsUsually temporary after Density or XERF, but we check how it progresses.
Density and XERF side effects summary — what is established and what is not
What is established
- Common reactions to Density and XERF: redness · heat · mild swelling — most gone within a day or two
- Burns appear within 72 hours; fat atrophy at 1–4 months (mean 2 months)
- No serious adverse events reported in the Density (16 people) or XERF (75 people) data
What we could not find
- Burn or fat atrophy rates for Density or XERF individually (the denominators are small)
- Human data on heating areas that contain non-dissolvable materials
- Evidence that aftercare rules such as ice packs or avoiding saunas after Density or XERF make a difference
Density and XERF side effects: frequently asked questions
Do Density and XERF have no side effects?
We cannot say Density and XERF have none. Common reactions are redness, heat and mild swelling, and RF lifting has rarely been reported to cause burns (within 72 hours) and fat atrophy (at 1–4 months). No serious adverse events occurred in the Density (16 people) or XERF (75 people) data, but the denominators are small.
Can the cheeks hollow after RF lifting?
Fat atrophy is a rare side effect of RF lifting, including Density and XERF, reported at about 4 per 10,000 treatments and appearing one to four months (mean two months) after treatment. If one spot looks sunken, you should be seen early.
Can Density or XERF cause burns?
Yes, Density and XERF can cause burns. A burn happens when the epidermis heats up too, and it usually shows as blistering or oozing within 72 hours. Density cools the epidermis with gas cooling and XERF with cryogen spray, but neither removes the risk.
Can I have Density or XERF where I have had filler?
The effect of Density or XERF heat on filler or non-dissolvable materials (PCL · PLLA · CaHA) has not been adequately established in people, so Miso Clinic avoids the area or spaces out the timing. Please tell us about any filler history before treatment.
Can I not have Density or XERF if I have a pacemaker?
With monopolar RF such as Density and XERF the current passes through the body, so as a rule Miso Clinic does not treat people with implanted electrical devices such as pacemakers or defibrillators.
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Who wrote this
Written and reviewed by Lee Chi-Hak, MD, medical director of Miso Clinic in Daegu, South Korea. Every study cited above is given together with its design, its size and the limitations the authors themselves recorded, and where we could not find data, we have said that we could not find any.
| 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
- Timing and frequency of RF adverse events (older device) — Fitzpatrick R et al., Lasers Surg Med 2003;33:232–242 (86 subjects): blistering 2.3% immediately · 3.8% within 72 hours; second-degree burns in 21 of 5,858 treatments (0.36%) — figures for the 2002 high-energy single-pass technique, not a current incidence.
- Fat atrophy — Narins RS et al., Dermatol Surg 2006;32:115–124. Appears at 1–4 months (mean 2 months), about 4 per 10,000 treatments. Notes that heavy anaesthesia blocks pain feedback.
- Course of redness — Fitzpatrick 2003 (periorbital, 86 subjects): redness 36.0% immediately → 16.7% at 72 hours → 3.9% at one month. Two clinical trials of non-invasive RF (Wanitphakdeedecha 2022 · Imaizumi 2026) advised immediate return to normal activity and usual cosmetics, with zero cases of pigmentation.
- Density human study — Oku K, J Cosmet Dermatol 2025;24(10):e70504, PMID 41090512. 16 adults · one session · 24 weeks · no control group. 3D imaging tightening distance 0.82 ± 0.36 mm; pain 1.4 ± 0.6 (5-point scale).
- 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.
- Isotretinoin and procedures — Mysore V et al., J Cutan Aesthet Surg 2017;10:186–194 (review of about 27 studies): concluded that no waiting period is needed before procedures including radiofrequency.
- Miso Clinic clinical protocols — criteria for indications, design by area, and the explanation and consent process before treatment. The source of the sentences marked “clinical judgement” in this column.
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.