Loss of firmness — “sagging” and “firmness” are not the same word

The short answer

When firmness feels lost, what has actually changed is usually one of two things — the skin’s own recoil has weakened, or the structures beneath have descended and left the skin in surplus. The two have different causes and call for different directions. In a 2021 study where 92 assessors rated 112 Korean women, how old a face reads split as wrinkles 37%, sagging 37% and pigmentation 26% — sagging carries the same weight as wrinkles. And only one factor has so far been confirmed to predict response. In a 2007 observational study following 25 patients for 12 months, the predictor of response was tissue mobility; skin thickness, fat depth and age were not predictors. So when we take hold of the tissue and move it during consultation, that is not a formality — it is the only predictor that has emerged so far.

What “loss of firmness” actually is

In measurements of 53 cadavers, cheek skin thickness was 1.51 to 1.97 mm while the superficial fat beneath it was 1.61 to 5.14 mm — the fat layer is roughly 3.2 times thicker. When firmness feels lost, it is statistically more likely that what moved was not the skin but what lies beneath it.

What is not the answer

“Boosters restore firmness.” Collagen boosters target dermal density. For weakened recoil the direction fits, but for structures that have descended it does not. Filling what has descended leaves the place it descended from unchanged.

“Lifting handles firmness completely.” Tightening tissue fits descent. But where the problem is the texture and density of the skin itself, tightening does little to change the impression at the surface.

“Four weeks have passed with no change, so it failed.” In the radiofrequency data, the 4-week point was not statistically significant, significance appeared at 12 weeks, and the clinical peak is reported at 4 to 6 months. Judging at 4 weeks makes a successful treatment read as a failure.

“It still looks the same in the mirror.” A mirror image and a photograph look different. In a study showing people their selfies, 56.6% of 198 participants preferred the mirror image. A face seen daily is one the eye adapts to, so changes go unnoticed — at 90 days, operators saw improvement in 92% of cases while patients themselves saw it in 42%. This is set out in when results appear.

How thick the evidence is, by class

The last row is the core of this article. On the question of who responds well, the answer confirmed so far is not age, not skin thickness and not fat depth, but how much the tissue moves. The difference between the two technologies is set out in HIFU and radiofrequency. In Korea the approved indication wording is generally “temporary improvement of facial wrinkles in adults through physical restoration”, and “lifting” or “improved firmness” is not the approved wording itself.

On combining treatments — objectively

Loss of firmness often involves several layers, so more than one approach may be involved. But we will write it precisely — “combining them works better” was not confirmed in the two randomised trials. Our reason for planning treatments in parallel is not that it is better but that the layers being addressed are different. Tightening, filling and raising density each act on a different layer. When the layer narrows to one, we do one thing. And we say plainly that when several things are done together, it cannot be worked out afterwards which one acted.

The order we look in consultation

1. We take hold of the tissue and move it. Mobility is the only predictor that has emerged so far.
2. We compare lying down with sitting up. If gravity changes it, the descent side; if it stays the same, the skin-density side.
3. We look for a boundary line. A face that breaks along a particular line points to the retaining ligaments, and we state the limit of what a procedure reaches before anything else.
4. We set the point of judgment in advance. For radiofrequency we look after 12 weeks, not at 4.
5. We keep photographs taken under the same conditions. The gap between how the operator and the patient see it widens to 92% versus 42% at 90 days.

Frequently asked questions

Who wrote this

References

1. Flament et al., 2021 — 112 Korean women, 92 assessors. Contribution to how old a face reads: wrinkles 37%, sagging 37%, pigmentation 26%
2. Sasaki, 2007 — 25 patients followed for 12 months. Tissue mobility alone predicted response; skin thickness, fat depth and age did not
3. Measurements of 53 cadavers — cheek skin thickness 1.51 to 1.97 mm, superficial fat 1.61 to 5.14 mm (about 3.2 times)
4. 2026 systematic review — radiofrequency, 15 studies and 1,230 patients, one randomised controlled trial; no head-to-head study between devices was identified
5. Human biopsy of microsphere PCL — 13 patients, dermal thickness +26.7% ± 9.3% at one year (P < 0.001)
6. Data on the perception gap — at 90 days, operators 92% versus patients 42%; mirror effect, 56.6% of 198 preferred the mirror image
7. Approved indication wording in Korea — “temporary improvement of facial wrinkles in adults through physical restoration”