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Picosecond laser: there are two trials asking whether the newer, dearer option really is better

In two split trials, picosecond won. On pigment (ABNOM), clearance 3.73 against 2.4 and post-inflammatory hyperpigmentation 27.77% against 54.44%; on acne scars, ECCA reduction 55% against 42% — and both trials had less pain on the picosecond side. But neither had an untreated arm, and the authors of one wrote the lack of objective evaluation into their limitations.

Last checked Sep 28, 2026

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What it is

A laser that fires in trillionths of a second. The long-established Q-switched lasers fire in billionths (nanoseconds).

What it is used for

For pigment, tattoos and acne scars.

How it is said to work

Putting the same energy in over a shorter time is said to break pigment particles by shock rather than heat. Less heat left in the surroundings is the core of that account.

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

At a glance

Session length
15–40 min
Pain
ModerateReported in a trialBoth trials had less pain on the picosecond side — 4.47 vs 5.16 and 4.3 vs 5.6. Note that the comparison is against another laser.
Downtime
3–7 days
Sessions
3–4 sessionsReported in a trialThe pigment trial used three sessions six months apart; the scar trial four at three-week intervals. The intervals differ greatly.
How long it lasts
6 monthsReported in a trialThe pigment trial judged six months after the final treatment. We have not verified material beyond that.
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.

A picosecond laser fires in trillionths of a second. The long-established Q-switched lasers fire in billionths — nanoseconds. A thousand times longer.

Putting the same energy in over a shorter time is said to leave heat less time to spread while pigment particles are broken by shock. So the claim is the same or better effect with fewer side effects.

This page sits in a slightly special place on this site.

On other pages in this layer we have written repeatedly that an A-versus-B design cannot separate 'both worked' from 'neither worked'. PRP, mesotherapy and erbium laser are like that.

But here A versus B is the right shape for the question.

Whether a pigment laser lightens pigment is what the pigment laser page is about. What this page has to ask is different — is the newer, dearer option really better? And for that question, a trial putting two devices on the two sides of the same person gives the best answer available.

And picosecond won in both trials. They are below.

But keep hold of the fact that what it beat was another laser, not doing nothing.

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

What is established

Early research

More pigment cleared than with a Q-switched laser, and half the pigmentation afterwards

A 2018 trial in JAAD from Shanghai Ninth People's Hospital. Split-face, single-blinded, randomised controlled.

The condition is acquired bilateral nevus of Ota-like macules (ABNOM) — bluish pigmented patches appearing symmetrically around the cheekbones, relatively common in East Asia.

30 patients took part. Matching areas were delimited on each face, one side treated with a picosecond alexandrite laser (PSAL, 755 nm), the other with a Q-switched alexandrite laser (QSAL, 755 nm).

Three treatments at six-month intervals, assessed six months after the final treatment by visual assessment and self-report.

Results:

  • clearance — picosecond 3.73 against Q-switched 2.4 (significantly better on picosecond)
  • pain — 4.47 against 5.16 (less on picosecond)
  • incidence of post-inflammatory hyperpigmentation — 27.77% against 54.44%
  • duration of post-inflammatory hyperpigmentation — 1.32 against 1.74 months (P < .001)

That third line is the most practical number here. The commonest problem with pigment lasers is getting new pigment instead of losing the old. That incidence was halved.

Now the limits, starting with the ones the authors wrote themselves — a small sample and a lack of objective evaluation.

Judgement was by visual assessment and self-report. There is no instrument reading of pigment. We write that into the endpoint field on the badge.

And it is single-blinded. The assessors may have been masked, but the participants could well have known which side was which. Pain and self-report are affected by that.

There is no untreated side. Both sides had a laser. So the trial does not answer 'does a laser lighten ABNOM'.

But the question this design can answer, it answered. Two sides of the same face, the same wavelength, different pulse width — only the thing being compared differed.

So it sits at 'early evidence'. 30 people, one trial.

  • Randomised controlled trial in people · 30 participants · 78 weeks · Compared with another active ingredient · Funding not declared · Endpoint scores from blinded assessors PMID 29288102
Early research

On acne scars it beat the non-ablative fractional laser

A 2020 Korean trial in JEADV. Prospective, randomised, split-face controlled, over 17 weeks.

The faces of 25 patients were split at random:

  • one side — a 1064 nm Nd:YAG picosecond laser using a diffractive optical element (P-DOE), four sessions at three-week intervals
  • the other — a 1550 nm non-ablative fractional laser (NAFL)

Follow-up ran eight weeks after the final sessions. Judgement used ECCA (a clinical acne scar grading scale), Investigator's Global Assessment, patients' reports, and histologic analysis.

Results:

  • ECCA per cent reduction — picosecond 55% against NAFL 42% (P < .05)
  • pain — 4.3 against 5.6 (less on picosecond)
  • IGA and subjective satisfaction ran the same way as ECCA
  • treatment-related side effects were also lower on the picosecond side (P < .05)
  • histology showed, on both sides, elongation and increased density of neocollagen, elastic fibres and mucin through the dermis

What is worth reading here.

First, there is histology. Uncommon in this layer. And it ran the same way on both sides — which allows the reading that the two devices do a similar kind of thing, to a different degree.

Second, several things went the same way. Effect, pain and side effects all landed on one side. Results that converge like that are rare on this site.

Third, it is still 25 people. And there is no untreated side.

Fourth, the authors attached the condition 'in Asian patients' to their conclusion. Because the side-effect profile of lasers differs in more pigmented skin, that condition is part of reading the result.

Fifth, and this is the part to be most careful with — this result is the same trial as the first entry on the non-ablative fractional laser page. What won on one page lost on the other. The same material appears on two pages, so do not read it as twice the evidence.

So it sits at 'early evidence'.

  • Randomised controlled trial in people · 25 participants · 17 weeks · Compared with another active ingredient · Funding not declared · Endpoint scores from blinded assessors PMID 32603006

Known risks

  • Post-inflammatory hyperpigmentation is the commonest problem with pigment lasers generally. On the picosecond side above it was 27.77%. Halved is still close to one in three.
  • Temporary redness, swelling and pinpoint bleeding follow.
  • Losing pigment so the skin goes pale (hypopigmentation) is reported with pigment lasers. The trials above did not report on it separately.
  • Sun protection is central to care before and after. Sunscreen is one of the items on this site carrying 'strong evidence'.
  • Melasma is a different situation. Melasma can worsen when a laser irritates it, so on the pigmentation side the judgement has to be more careful.
  • This is a clinical procedure.

What is not established

  • We could not include a trial with an untreated arm. Both trials compare against another laser.
  • The 2018 trial has no objective evaluation — no instrument reading of pigment. The authors wrote that into their limitations.
  • 30 people and 25 people.
  • The two trials used different wavelengths and mechanisms — 755 nm alexandrite and 1064 nm Nd:YAG with a diffractive optical element. The single phrase 'picosecond laser' does not point at one device.
  • We could not include material on tattoo removal on this page.
  • 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

  1. PubMed — 미국 국립의학도서관 문헌 데이터베이스National Library of Medicine · Checked on 2026-09-16