Ingredient Beauty BenefitsRoute · Device-based
Subcision: the blinded raters saw no difference; the people treated did
A needle is passed under the scar to cut the fibrous bands pulling it down. In a trial that added suction, blinded dermatologists found no difference at one month or four, while in the same trial participants rated the suction side 37% improved against 24%.
Last checked Sep 20, 2026
At a glance
- Session length
- 20–40 min
- Pain
- Painful
- Downtime
- 7–14 days
- Sessions
- 1–5 sessionsReported in a trialOne trial did five, four weeks apart; the other did one. How many is right has not been settled.
- How long it lasts
- Not applicable
- Relative cost
- Middle
- How well established
- Moderate evidence
“Reported in a trial” means a number a study on this page actually reported. “Typical range” is not a measured value but roughly how it is usually done, and it varies by clinic and by person.
Cost is not an amount but a band: where this procedure falls when the ones on this site are lined up per session, or per area treated. Real prices differ several-fold by clinic and by how much is treated, so they are not given here. Surgery is measured on a different scale and cannot be compared with this band.
This is not how large the effect is but how well confirmed it is. It shows the highest grade among the findings on this page.
Among depressed acne scars, the rolling type is not caused by thinned skin. The floor of the scar is tethered to the tissue underneath by fibrous bands, and that tether is what makes it look pressed in.
Subcision cuts those bands. A needle or cannula is passed under the scar and moved to release the adhesion. It does not burn or abrade; it removes the pull.
It is done under local anaesthetic, and bruising follows.
The most important thing on this page is that the two trials show different things. One enrolled five people; in the other, the blinded raters and the people treated gave different answers. Both are below.
Other options for the same problem are on the fractional laser, microneedling and microneedle radiofrequency pages.
What is established
Repeated sessions beat doing nothing — but there were five people
This is a 2024 trial at Northwestern University. People with rolling scars on both cheeks had one side randomised to treatment while the other side received nothing.
Five subcisions, four weeks apart, with follow-up visits at weeks 20 and 36 from the first treatment. Assessment came from the participant, one blinded live rater, and two double-blinded dermatologists working from photographs, using a five-point scale, a percentage improvement scale, and a modified global scarring grade.
The result: global scarring scores fell more on the side that had multiple subcisions.
But five people took part.
The design is good — randomised, same person on both sides, double-blinded raters. That shape is rare in this layer. It was applied to five people.
A direction seen in five people is a reason to design the next trial; it is not enough to conclude that the treatment works. That is why this item is graded 'early research'.
- Randomised controlled trial in people · 5 participants · 36 weeks · Compared with no treatment · Funding not declared · Endpoint scores from blinded assessors PMID 38850371
Adding suction changed nothing for the blinded raters — but the participants saw it
This is a second 2024 trial from the same group. Here both cheeks had one subcision, and then one side had ten sessions of suction added. Randomised, split-face, evaluator-blinded.
Photographs were assessed at baseline, one month and four months. The primary outcomes were the validated Acne Scar Severity Scale, the Acne Scar Improvement Grading Scale and a modified global scarring grade, plus participant preference.
What was analysed: 28 treatment areas and 154 treatments. (The abstract does not state a separate number of people, so this site leaves the sample size blank.)
The results split.
- The blinded dermatologists found no difference between the two sides at either one month or four months.
- The participants' own percentage-improvement ratings did differ at one month — 37% for subcision plus suction against 24% for subcision alone (P = .04). By four months that difference was gone (P = .37).
- Participants preferred the combination side at one month (50% vs 21%) and at four months (43% vs 21%).
That mismatch is the most valuable result on this page.
When raters working from photographs see nothing and the person treated sees something, several explanations fit. The suction side may have been redder or more swollen, so it felt like something was happening. Ten extra visits create expectation. Or there may have been a real change in texture that a photograph does not capture.
This trial cannot tell those apart. What is worth remembering is that the one-month difference was gone by four months.
- Randomised controlled trial in people · sample size not reported · 16 weeks · Compared with another active ingredient · Funding not declared · Endpoint scores from blinded assessors PMID 38847979
Known risks
- Bruising. Cutting beneath the skin bleeds, and bruises last one to two weeks.
- Swelling and soreness for several days, felt once the local anaesthetic wears off.
- Nodules can form where the released area fills in excessively; they are felt as firm lumps.
- Hyperpigmentation can persist, and the darker the skin, the more this matters.
- Tell them in advance if you take anything that affects clotting.
- Both trials above tracked adverse effects as an outcome. Ask for the specific list where you have it done.
What is not established
- How many sessions is right is unsettled. One trial used five at four-week intervals; the other used one.
- We found no trial measuring how long it lasts. The longest follow-up was 36 weeks.
- We could not include a randomised head-to-head against another procedure. Whether to choose this over fractional laser or microneedle radiofrequency cannot be answered here.
- Which scars it suits has not been settled by trial. Rolling scars are the convention, but we found no randomised comparison separating icepick and boxcar types.
- Both trials come from the same research group.
Whether to have it done is a decision to make with a doctor.
What this article relies on
- PubMed — 미국 국립의학도서관 문헌 데이터베이스National Library of Medicine · Checked on 2026-09-16
- PDO screw threads versus fractional CO(2) laser, after subcision, for atrophic acne scar remodelling: a randomized group-based comparative studyArchives of dermatological research · 2025 · PMID 39804529