Route · Injection

Intralesional steroid: there is a trial with a clear comparator, and steroid alone was the arm that lost

In a 72-person randomised trial, a triple combination (steroid + 5-FU + hyaluronidase) beat steroid alone at every time point (54.55% vs 36.65% improvement at final follow-up). But the trial had no blinding and no untreated control arm. The authors said so themselves under limitations.

Last checked Sep 21, 2026

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What it is: Injecting a steroid directly into a raised scar. Used for keloids and hypertrophic scars.
What it is used for: Repeated several times at three-to-four-week intervals, in a clinic.
How it is said to work: It is said to reduce the excess collagen being laid down inside the scar and to suppress inflammation.

There are no numbers and no citations in this box. What has been established, and how far, is below.

At a glance

Session length: 5–15 min
Pain: Painful
Downtime: 0–1 days
Sessions: 1–4 sessionsReported in a trialThe trial above ran every three weeks for four sessions, or until complete flattening.
How long it lasts: 3 monthsReported in a trialFollow-up in the trial above was three months, with no recurrences inside it. We have not verified longer.
Relative cost: Lowest
How well established: Early research

“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.

Korean classification Being checkedThe regulatory class has not yet been confirmed against a primary document. It will be filled in once it is.

Keloids and hypertrophic scars are what happens when collagen is laid down in excess where skin has healed. Injecting a steroid directly into them has long been the first thing tried.

First, the character of the trial on this page. Unlike most of this layer, it is clear what it compared against — steroid alone was the control arm.

And in that trial, steroid alone was the arm that lost.

This is exactly the kind of result we want to record as it stands. The longest-used option is not necessarily the best one.

The trial also had no blinding. The authors wrote that under limitations, and this page does not raise it above what that allows.

This site does not deal in prices, clinics or reviews. What suits a particular scar is decided in a consultation.

What is established

Early research

The triple combination beat steroid alone at every time point

A 2025 randomised controlled trial at a tertiary hospital in Puducherry, India.

72 patients aged 18 and over, with keloids at any site and no prior treatment, took part. They were randomised into two arms.

Group A — intralesional triple combination: triamcinolone acetonide plus 5-fluorouracil plus hyaluronidase
Group B — intralesional triamcinolone acetonide alone

Treatments ran every three weeks for four sessions, or until complete flattening. Assessment used the Vancouver Scar Scale every three weeks, then monthly for three months after treatment ended.

Results:

Group A — 0.58 ± 0.5 (7.08%) at three weeks, rising to 4.47 ± 1.29 (54.55%) at final follow-up
Group B — 0.08 ± 0.28 (0.95%) at three weeks, rising to 3.08 ± 0.81 (36.65%)
Group A was significantly better at every time point (p < 0.05)

Post-procedure pain lasting a few hours occurred in three patients in A and two in B, with no difference between groups (p = 0.642). No one had a recurrence during the study.

Now how to read it.

We carry the authors' own stated limitations across: small sample, single centre, short follow-up, no blinding, and no patient-reported outcome measures.

Of those, no blinding weighs particularly heavily on this endpoint. The Vancouver Scar Scale is not a machine reading; it is a score a person assigns by eye. If the assessor knew which arm a patient was in, that score can lean toward expectation.

This is the same thing we wrote on PRP and subcision. Who assigned the score matters as much as the badge.

So it sits at 'early evidence'. Randomised, with 72 people, is not a bad size for this layer; the missing blinding does not allow more.

Randomised controlled trial in people · 72 participants · 24 weeks · Compared with another active ingredient · Funding not declared · Endpoint scores from blinded assessors PMID 40357976

Not established

Both arms improved — but nothing was left untreated

Same trial, same 72 people. The entry above was the comparison between arms. This one is the part where each arm improved against its own baseline.

The paper reports that both groups improved significantly from baseline at every follow-up. The steroid-alone arm ended up 36.65% better.

But there was no untreated arm in this trial.

Here is why that matters.

Keloids sometimes flatten a little on their own over time. And participants in a scar trial generally live differently for the duration — avoiding sun, reducing irritation. With no control arm, all of that is counted as the injection's work.

This is the recurring problem of this whole layer. As the PRP page says, almost every randomised trial in aesthetic medicine is A versus B, and that design cannot separate 'both worked' from 'neither worked'.

This procedure does have one extra circumstance. Keloids are not lesions expected to resolve on their own; left alone they often grow. So an untreated arm is ethically hard to justify in the first place. We accept that, and we still do not erase the fact that there was no control.

Hence 'not established' here. This trial did not prove 'injections make it better'. What it proved goes as far as 'the triple combination beat steroid alone'.

Randomised controlled trial in people · 72 participants · 24 weeks · Compared with no control group (before-and-after only) · Funding not declared · Endpoint scores from blinded assessors PMID 40357976

Known risks

The injection site can become depressed. The steroid is understood to atrophy surrounding fat, and this is the best-known adverse effect of the procedure.
Surrounding skin can lose pigment. It shows more on darker skin.
Dilated capillaries can appear as fine red vessels.
The trial above reported pain lasting a few hours after the procedure in both arms.
Keloids recur. Follow-up in the trial above was three months, and no one recurred within it. Anything longer is outside what this page verified.
This is a clinical procedure. What suits a particular scar is decided in a consultation.

What is not established

We could not include a blinded trial on this page. The authors of the trial above said so under limitations.
No trial with an untreated control arm. There is an ethical reason for that, but the absence stands.
Follow-up beyond three months is something we have not verified. Recurrence often shows up later than that.
No patient-reported outcome measure in the trial above. Scars sit where people can see them, so how the person feels about it is an important endpoint.
We do not state concentrations or doses. They are not in the abstract.
We have not yet opened the primary Korean regulatory classification, so it stays 'being verified'.

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