Route · Device-based

Erbium laser: it tied with CO2 — but nothing was left untreated

In a 40-person split-face, double-blind trial, one side had fractional CO2 and the other fractional Er:YAG, three monthly sessions. Both sides showed significant wrinkle reduction, with no appreciable difference between the lasers. But post-treatment discomfort was more pronounced with CO2.

Last checked Sep 21, 2026

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What it is: A laser at a wavelength (2940 nm) absorbed strongly by water, used to remove a thin layer of the skin surface.
What it is used for: For wrinkles and texture. Usually fractional — making a pattern of tiny holes.
How it is said to work: Injuring the surface deliberately is said to rebuild collagen as it heals. Same principle as the CO2 laser; the wavelength differs.

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

At a glance

Session length: 20–40 min
Pain: Painful
Downtime: 3–7 days
Sessions: 3 sessionsReported in a trialThe trial above ran three monthly sessions.
How long it lasts: 3 monthsReported in a trialThe trial above read to three months after the last session. Beyond that we have not verified.
Relative cost: Higher
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.

Er:YAG runs at 2940 nm. Water absorbs that wavelength strongly, so it vaporises a very thin layer where it lands and does not carry far below. That is why it is described as working shallower, leaving less heat, than the CO2 laser at 10600 nm.

The trial on this page is unusually clean for this layer. Different lasers on the two sides of the same face, assessed by two independent dermatologists not involved in the treatment, with an instrument measuring the biomechanics of the cheeks as well.

But the comparator is another laser.

This is the problem set out on the PRP page. 'Both sides improved' can mean both worked, or that neither did much and time and expectation moved that far on their own. With no untreated cheek, the two cannot be separated.

One thing this design does answer clearly. Because the same person went through both, the direct comparison of pain and recovery between the two lasers is trustworthy. That is the second entry below.

This site does not deal in prices, clinics or reviews.

What is established

Not established

Both lasers reduced wrinkles, and neither beat the other

A 2017 trial at Shahid Beheshti University of Medical Sciences in Iran.

40 patients with facial wrinkles took part, in a randomised, double-blind, split-face design.

One side of the face — fractional CO2
The other side — fractional Er:YAG

Three monthly treatments, assessed at baseline, one month after each session, and three months after the last.

Two things did the assessing:

clinical outcome judged by two independent dermatologists not involved in the treatment
cutaneous resonance running time (CRRT) — an instrument measure of the biomechanical properties of the cheeks

Results:

both sides reduced facial wrinkles significantly (p < 0.05)
with no appreciable difference between the two lasers
mean CRRT also fell significantly from baseline on both sides
no serious long-standing adverse effect on either side

How to read it.

What is good about the design first. Two sides of the same face cancel out age, skin and habits. The assessors were not involved in treating. An instrument measure sat alongside clinical judgement. Not many trials in this layer bring that much.

But no cheek was left untreated.

So in the sentence 'both sides fell significantly', the laser's share cannot be extracted. Over months of treatment people generally take more care with the sun and with their skin. And a wrinkle assessment is a score a person gives looking at photographs.

And 'no difference' is not 'the same'. Failing to separate two lasers in 40 people can mean there is nothing to separate, or that there was not the power to do it.

So this entry is 'not established'. The design was good; the comparator cannot answer this question.

Randomised controlled trial in people · 40 participants · 24 weeks · Compared with another active ingredient · Funding not declared · Endpoint scores from blinded assessors PMID 27885522

Early research

Discomfort afterwards was lower with erbium — a question this design can answer

Same trial, same 40 people, same faces.

The investigators also recorded adverse effects and participant satisfaction.

Result: discomfort after treatment was reported as more pronounced on the CO2 side.

The authors' conclusion carries this too — both lasers gave considerable clinical improvement with no serious adverse effects, but post-treatment discomfort seems lower with Er:YAG.

Why we grade this differently from the entry above.

Up there, the comparator being another laser blocked the conclusion. Here it is an advantage.

Because the question is not 'does a laser reduce wrinkles' but 'which of these two lasers is less unpleasant'. For that question, a design where the same person goes through both gives the best answer available. Pain thresholds differ widely between people, and this design cancels that difference automatically.

It is still what the participants felt. We mark that endpoint separately. And the participants did not know which side was which — the design was double-blind — which makes the result a little more trustworthy.

So it sits at 'early evidence'. One trial, 40 people, no further.

There is another reason we pulled this out as its own entry. One of the things people actually ask when choosing a procedure is how much it hurts and how long they will need to recover. That question is often easier to answer than the one about effect, and it is usually the one left out of the writing.

Randomised controlled trial in people · 40 participants · 24 weeks · Compared with another active ingredient · Funding not declared · Endpoint self-reported improvement PMID 27885522

Known risks

It removes surface. Redness, swelling, crusting and flaking follow.
In the trial above, discomfort afterwards was more pronounced with CO2. Erbium is less, not none.
Post-inflammatory hyperpigmentation is a known risk of ablative lasers generally, and more of a problem on darker skin. The trial above did not report on it separately.
Keeping the sun off is central to aftercare, as generally described. See the sunscreen page alongside this one.
A history of herpes changes how the procedure is managed before and after. Check in a consultation.
This is a clinical procedure.

What is not established

We could not include a trial with an untreated side. It is the largest hole on this page.
40 people, one trial.
It was read only to three months after the last session. What happens later is unverified.
Pigment risk on darker skin was not reported separately in the trial above.
How many sessions is right — no settled data found. The trial above used three.
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