Why do some reviews say Density or XERF “did nothing”?
For the same device you will find reviews saying “it lifted right up” alongside ones saying “a waste of money”. Both can be true. Reviews split less because of the device than because of when results were judged, what the concern was, and who was doing the rating.
The short answer
Reviews saying Density or XERF had no effect mostly come from four things. (1) Judging too early — in one RF lifting study clinical assessment was not significant at 4 weeks and became significant at 12 weeks. (2) A concern RF does not treat — a face that has lost volume, or thin, dull skin, is not a problem that radiofrequency solves. (3) Differences between raters — one review found that at the same 90 days practitioners judged 92% improved and patients 42%. (4) Expectations without a control group — in an Ulthera randomised trial, 47% of people who received no treatment at all were rated “improved” on blinded photo assessment, and all the Density and XERF data lack a control group.
What happens if Density or XERF results are judged too early?
RF lifting results such as those of Density and XERF are judged two to three months after treatment, not the next day. The tight feeling right after treatment is immediate collagen contraction and swelling that settles within days; the lasting change is remodelling over weeks to months.
| Time point | What was measured | Source design |
|---|---|---|
| RF lifting at 4 weeks | Device-measured elasticity significant; clinical assessment not significant | 20 Korean women · no control group |
| RF lifting at 12 weeks | Clinical assessment of jawline and nasolabial folds significant | Same study |
| XERF at 30 days → 90 days | Physician-rated 84.6% → 92.3% | 39 people · unblinded · manufacturer support |
The period two to four weeks after Density or XERF when people feel “nothing has changed” overlaps with the time when immediate contraction has faded but new collagen is not yet sufficient.
What if the concern was one Density and XERF do not treat?
| Concern | Why RF struggles | The direction that fits |
|---|---|---|
| Hollow cheeks or temples with Density or XERF | Heat does not create volume — the area may look more hollow | Filler · CaHA |
| Thin, dull skin with Density or XERF | Not the layer RF targets | Skin boosters · collagen boosters |
| Skin so lax it folds with Density or XERF | Beyond the range of non-surgical devices | Surgical consultation |
| Melasma or flushing with Density or XERF | Territory of pigment devices | Pigment treatment |
| Fat reduction with Density or XERF | No human facial data | Body-contouring devices · a different consultation |
One RF lifting study (25 people) found that response was predicted not by age but by how lax the tissue was. If the starting conditions do not fit, the same Density or XERF treatment will look like a smaller result.
Do Density and XERF results depend on who assesses them?
Even for the same patient at the same time point, improvement rates for lifting devices such as Density and XERF vary widely depending on who does the rating. In a review of 16 ultrasound lifting studies, practitioners judged 92% improved at 90 days, but patient self-assessment was 42%.
| Data | Practitioner · unblinded | Blinded assessment | Patient |
|---|---|---|---|
| Ultrasound lifting, 16 studies (90 days) | 92% | — | 42% |
| Ulthera randomised trial (90 days) | 96.8% | 54.2% (untreated control 47.0%) | 94.7% |
| XERF 39-person study (90 days) | 92.3% | None | — |
A review is one patient’s assessment, while the improvement rates in clinic marketing for devices such as Density and XERF are usually practitioner assessments. That the two numbers differ is a measured phenomenon.
What does the 47% untreated control group mean for Density and XERF data?
In a randomised trial registered by the Ulthera manufacturer (NCT04795622), 47.0% of people who received no treatment at all were rated “improved” by blinded assessors on photos. The Ulthera-treated group was 54.2%, and the difference was not statistically significant (odds ratio 95% confidence interval 0.7530–2.4365).
It means lighting, angle, swelling, expression and how someone looked that day all feed into photo assessment, and this applies to every data set that compares only before and after without a control group. The Density data (16 people) and the XERF data (20, 39 and 16 people) all lack a control group. That is why Miso Clinic describes Density and XERF figures as “observations with measurements attached”, not as “proof”.
Reading this Ulthera result as “Ulthera or RF does not work” would be wrong. It means superiority was not confirmed in one trial, with one session, at 90 days, in mild-to-moderate sagging — and the same caution applies to uncontrolled Density and XERF data.
How to check Density or XERF results properly
- Take photos before Density or XERF under the same lighting, angle and expression, and retake them under the same conditions two to three months later for comparison
- Judge Density or XERF at two to three months — do not decide on more treatment during the unclear two-to-four-week window
- Before starting, check that the concern is one RF treats — lost volume or thin skin needs a different treatment before Density or XERF
- Ask where the Density or XERF numbers come from — who assessed them, and whether there was a control group
Density and XERF results: frequently asked questions
I had Density and I do not think it worked.
If it has not yet been two to three months since Density, it is too early to judge. In RF lifting research, clinical assessment was not significant at 4 weeks and became significant at 12 weeks. Compare before-and-after photos taken under the same conditions, and we will also check whether the concern was one RF does not treat, such as lost volume.
Why are XERF reviews a mix of good and bad?
XERF reviews often split because the timing of judgement, the type of concern and the person rating differ. One review found that at the same 90 days practitioners judged 92% improved and patients 42%. Reviews cannot serve as evidence of XERF’s effect, and under Korea’s Medical Service Act they cannot be used in advertising either.
Have Density and XERF results been proven?
There is human data on Density (one study, 16 people) and XERF (three studies, 20, 39 and 16 people), but none has a control group. In a randomised trial 47% of people who received no treatment were rated improved on photos, so uncontrolled Density and XERF figures should be read as observation, not proof.
If it did not work, should I just have more shots?
No human study has randomly compared shot counts for either Density or XERF, and repeating treatment more than needed raises the risk of burns. We first check whether the concern is one RF treats.
How long does it take for results to appear?
For RF lifting such as Density and XERF, one study found device-measured elasticity significant from 4 weeks and clinical assessment at 12 weeks. Miso Clinic judges results two to three months later using photos taken under the same conditions.
Read next
- Ulthera (Ultherapy) — a device we do not have, and its evidence is thicker than ours
- When results actually start to appear, and when you should judge them
- Why the same treatment gets opposite reviews
- How long Density and XERF results last
- Density lifting in Daegu: a complete guide
- XERF lifting in Daegu: a complete guide
Product pages
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
- Timeline of RF results — Cosmetics 2024;11(3):71 (20 Korean women: clinical assessment not significant at 4 weeks · significant at 12 and 24 weeks; device-measured elasticity from 4 weeks) · Weiss 2026 (84.6% at 30 days → 92.3% at 90 days) · Fitzpatrick 2003 and Edwards AF et al., Dermatol Surg 2013;39:104–110 (peak at 4–6 months). None has a control group.
- Improvement rates that depend on the rater — review of 16 ultrasound lifting studies (IJERPH 2023;20(2):1522): at 90 days, practitioners 92% vs patients 42%. Werschler 2016 (20 subjects): at one year, blinded assessment 43% vs patient satisfaction 95–100%; quantified lift was greatest at 90 days and fell to 22–33% at one year.
- Ulthera randomised trial with an untreated control — NCT04795622 (registered by the manufacturer Merz and others; results posted). Five centres in China, 101 treated vs 100 untreated, one session, 90 days. Blinded photo assessment 54.2% vs 47.0%, odds ratio 1.3545 (95% confidence interval 0.7530–2.4365) — not statistically significant. Unblinded investigator assessment 96.8% · patient assessment 94.7%.
- What predicted response — Sasaki G et al., Aesthetic Surg J 2007;27(4):376–387 (25 subjects, mean age 52.3, 12 months). Only tissue mobility was significant; age was not a significant predictor. The sample is small.
- 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.
- Medical advertising law — Korea’s Medical Service Act, Article 56(2). It prohibits advertising through treatment testimonials, comparison with other medical institutions, superlative claims and similar.
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.