XERF vs Density: what is the difference? — Differences in structure and data, and the fact that there is no head-to-head study
XERF and Density are RF devices that Miso Clinic has both of. So we are often asked, “Which of the two is better?” To be frank from the start, there is no study comparing the two devices side by side in the same people. Instead of a ranking, this article sets out how they differ in structure, effectors and published human data, and states, as clinical judgement, the criteria Miso Clinic uses to put one of them first.
The short answer
The difference between XERF and Density lies in how they deliver radiofrequency — XERF uses 6.78 MHz + 2 MHz monopolar delivery alone, and Density delivers monopolar and then bipolar in sequence. No study compares the two devices directly, and no direct comparison between RF devices has been identified at all (systematic analysis of 15 studies · 1,230 people). The published human data are Density in 16 people · 1 session · 24 weeks (Oku 2025) and XERF in three studies (20, 39 and 16 people, longest follow-up about 3 months), none with a control group. Miso Clinic (4F Bombom Building, 125 Dongdeok-ro, Jung-gu, Daegu, South Korea; +82-53-428-2700) has both devices and decides which to put first by skin thickness, depth of sagging, area and pain burden (clinical judgement).
How does the structure of XERF differ from Density?
Both devices create heat with radiofrequency, but they deliver the current differently.
| Item | XERF | Density |
|---|---|---|
| Manufacturer | Lutronic (now Cynosure Lutronic) | Jeisys Medical |
| Delivery | Monopolar | Monopolar → bipolar in sequence |
| Frequency | 6.78 MHz + 2 MHz | Not confirmed in published material |
| Output · control | Outside the published specifications we could confirm | Up to 400 W, RIC automatic impedance adjustment |
| Cooling | ICD gas cooling (manufacturer material alone) | Five-level gas cooling, real-time skin temperature display |
| Korean approval | Classified as a general-purpose electrosurgical unit | MFDS-approved medical device (approval number not verified) |
XERF divides depth by using two frequencies, while Density is designed to heat the deeper layer and then the shallower layer by delivering monopolar and then bipolar in sequence. The principle of XERF is set out separately in How XERF RF works: the two frequencies.
How do the effectors and tips differ?
Both devices change tips according to the area. The number beside each tip name is the shot count sealed into the tip, not a recommended dose.
| Device | Tip | Size · sealed shot count |
|---|---|---|
| XERF | i05 | 5×10 mm · 400 shots — used around the eyes at Miso Clinic (Eye XERF) |
| XERF | i10 | 10×10 mm · 300 shots — narrow areas |
| XERF | E40 | 20×20 mm · 600 shots — broad areas |
| XERF | E60 | 20×30 mm · 600 shots — broad areas |
| Density | ALPHA · Eye · Face · Body | 600 · 600 · 1,000 · 600 shots |
Because XERF tip area comes in four steps, it is relatively easy to divide the face and design it area by area (clinical judgement). However, no data comparing the effect of different XERF tip sizes have been identified. Effector choice continues in XERF handpieces (effectors): how to choose.
How do the published human studies differ?
Neither device has much human data, and none of it has a control group.
| Device | Study | Subjects · sessions · follow-up | Main findings |
|---|---|---|---|
| Density | Oku 2025 | 16 Japanese adults · 1 session (about 500–600 shots) · 24 weeks | Tightening 0.82 mm, lower-face thickness −0.89 mm, 15 of 16 improved on GAIS, pain 1.4/5 |
| XERF | Hwang 2025 | 20 women · 1 session · 12 weeks | Blinded photo identification 80%, GAIS 2.75/4, pain without anaesthesia VAS 4–5 |
| XERF | Weiss 2026 | 39 people · 2 sessions · 90 days (manufacturer support) | Improvement 84.6% at 30 days → 92.3% at 90 days |
| XERF | Erlich 2026 | Retrospective, 16 people · 1 session · 3 months | E60 · E10 · E5 combination, lower face 24–36 kJ |
The measurement tools, subjects, sessions and follow-up periods all differ, so these numbers cannot be placed side by side and ranked. Density data go to 24 weeks and XERF data to about 3 months, which is another difference. The Density paper has a single author, and the values in the abstract (± 0.36) and main text (± 0.34) differ.
How does pain differ?
The pain figures also use different scales and cannot be compared directly. The Density study reported 1.4 on a 5-point scale (Oku 2025), and one XERF study reported VAS 4–5 without anaesthesia (Hwang 2025). The scales differ, and so do the anaesthesia conditions.
There is one more reason pain management matters. In data from older monopolar devices, fat atrophy occurred at about 4 per 10,000 treatments, with the observation that heavy anaesthesia blocks pain feedback (Narins 2006; not a current incidence). So rather than eliminating pain, Miso Clinic places weight on adjusting while listening to how the treatment feels (clinical judgement). Pain and anaesthesia with XERF are discussed in XERF side effects, read as a timeline.
Which of the two does Miso Clinic put first?
The following is Miso Clinic’s clinical judgement. It is not a criterion from comparative studies.
| This kind of face | Considered first |
|---|---|
| Thicker skin with relatively deep sagging below the cheeks and along the jawline | Density |
| Needs to be designed area by area, such as around the eyes and mouth | XERF |
| Wants the eye area treated together with the face | XERF (i05 + face effectors) |
| Thin skin, wanting to reduce the burden on the surface | Decided by looking at settings and order together |
| Hollowing is the main concern | Neither first — consider filler |
A more detailed way of sorting by condition is in Density vs XERF: differences and who each suits, and the comparison in table form is in Density vs XERF: the difference.
Can I have XERF and Density together?
No study has been identified that looked at the result of using both devices on one face. So there is no basis for saying “doing both together is better”.
- Rather than layering two devices in one visit, Miso Clinic’s default is to design with one device, look at the result at around 3 months, and then decide the next step (clinical judgement).
- If we judge that different areas suit different devices, we explain why in consultation and decide together (clinical judgement).
- Layering heat-based devices also layers the heat burden. So we do not use “more” as the standard.
All our XERF columns are in XERF lifting in Daegu: which skin it suits, and lifting by layer is set out in Lifting for facial sagging: which layer.
XERF vs Density: frequently asked questions
Which is better, XERF or Density?
There is no study comparing the two devices directly, so there is no basis for ranking them. Miso Clinic decides which to put first by skin thickness, depth of sagging, area and pain burden (clinical judgement).
How do XERF and Density differ in principle?
XERF uses 6.78 MHz + 2 MHz monopolar delivery alone, and Density delivers monopolar and then bipolar in sequence.
Does Miso Clinic have both devices?
Yes. Miso Clinic has both XERF and Density. It does not have Thermage or Ulthera.
Which one lasts longer?
There are no data to compare. Density data cover 16 people over 24 weeks, XERF data go to about 3 months at the longest, and none has a control group.
Is it better to have both devices together?
No study has been identified that looked at using them together. Miso Clinic’s default is to design with one device, look again at around 3 months, and then decide the next step (clinical judgement).
Where can I have a XERF or Density consultation in Daegu?
Miso Clinic is at 4F Bombom Building, 125 Dongdeok-ro, Jung-gu, Daegu, in front of Exit 1 of Kyungpook National University Hospital Station. +82-53-428-2700. Weekdays 11:00–19:00, Saturdays 10:00–16:00 (no lunch break); closed Sundays and public holidays.
Read next
Product pages
Who wrote this
Written and reviewed by Lee Chi-Hak, MD, director of Miso Clinic, Daegu. The treatment standards and injection design set out here are the ones we use in practice.
| 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
- XERF specifications — Lutronic published data: monopolar, 6.78 MHz + 2 MHz, handpieces i05 (5×10 mm · 400 shots) · i10 (10×10 mm · 300 shots) · E40 (20×20 mm · 600 shots) · E60 (20×30 mm · 600 shots). Classified in Korea as a general-purpose electrosurgical unit; advertising marking “General-purpose electrosurgical unit combination-2024-16-054”.
- Density specifications — Jeisys Medical published data: sequential monopolar → bipolar delivery, up to 400 W, RIC automatic impedance adjustment, five-level gas cooling, real-time skin temperature display, tips ALPHA 600 · Eye 600 · Face 1,000 · Body 600 shots (the count sealed into each tip). Approved as a medical device by the MFDS; we could not verify the approval number itself.
- Density human data — Oku K, J Cosmet Dermatol 2025;24(10):e70504, PMID 41090512. The full text names DENSITY (Jeisys Medical). 16 Japanese adults (1 man · 15 women, mean age 49.4 ± 6.1) · one session of about 500–600 shots · 24 weeks · no control group · single author. Tightening 0.82 mm, lower-face thickness −0.89 mm, 15 of 16 improved on GAIS, pain 1.4/5, no burns, persistent erythema or scarring reported. The abstract (0.82 ± 0.36) and the main text (± 0.34) give different values.
- 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.
- Evidence for comparing RF devices — Aesthetic Surgery Journal Open Forum 2026, systematic analysis of the literature (15 studies · 1,230 people, one randomised controlled trial). It states that no direct device-to-device comparison was identified.
- 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.
- XERF cooling method — the description of ICD gas cooling in Lutronic’s published material. The manufacturer’s published material is the sole source, and we could not find independently verified data.
- Medical advertising law — Medical Service Act of Korea, Article 56(2), which prohibits testimonial advertising, comparison with other clinics, superlative claims and advertising that guarantees or implies a guaranteed treatment effect.
- Miso Clinic practice guidance — indication criteria, site-by-site design, and the explanation and consent procedure. This is the source for every sentence marked as clinical judgement.
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.
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