What the research shows
Fractional lasers make columns of tiny controlled wounds, and the skin builds new collagen and elastic fibers over the following months (Sirithanabadeekul 2021). Fractional CO2 laser is the most studied. A review of it advised setting the number of sessions, the interval and the energy for each patient, and adding a second method for deep ice-pick scars (Xu 2018).
Laser and microneedling give similar improvement. A 2026 pooled analysis found no clear difference in scar reduction, with a slightly higher chance of a clear success after CO2 laser and more dark patches after CO2 laser than after plain microneedling (Batool 2026). An earlier review found no difference in most of the comparisons it read (Nobari 2023), and a trial of nonablative laser against microneedling found equal results with no dark patches and less downtime after microneedling (Cachafeiro 2016).
Radiofrequency microneedling, which heats the skin through the needles, matched CO2 laser in two split-face trials. Patients had less pain and redness and a faster recovery on the radiofrequency side (Qu 2025, Li 2026).
Combinations work better than single treatments. Across all treatment types, laser plus platelet-rich plasma (PRP) or filler ranked first for reducing scar depth, and laser plus a chemical peel ranked first for patient satisfaction (Wu 2025). Among needling options, microneedling with a peel did best, and every combination beat microneedling alone (Li 2024). PRP after CO2 laser gave a better result and shorter downtime, and PRP spread on the skin worked as well as injected PRP with less pain (Gawdat 2014).
Skin color changes the risk. In Asian patients treated with fractional CO2 laser, about half had dark patches at one month and about 1 in 10 still had them at six months (Chan 2010). In skin types IV to VI, nonablative laser improved scars, and dark patches were common, more so at higher densities, and faded on their own (Alexis 2016).
Where surgeons disagree
- Waiting after isotretinoin. The long-standing rule is to wait six months after the acne drug isotretinoin before laser. A trial found normal healing with nonablative laser within one month of stopping (Saluja 2017), and a split-face trial found CO2 laser during isotretinoin gave better scar scores than laser six months later (Taleb 2024).
- Laser or needling as the main treatment. Some favor CO2 laser for its slightly higher rate of clear success (Batool 2026). Others favor needling because results match with fewer dark patches and less downtime (Cachafeiro 2016, Li 2026).
- Which pairing to choose. The analysis that covered all treatments put laser plus PRP or filler first (Wu 2025); the one limited to needling put microneedling plus a peel first (Li 2024).
What is new
- Alternating CO2 laser and radiofrequency microneedling from one session to the next reduced scars more than laser alone, with more pain during treatment and similar side effects (He 2026).
- Growth factor applied after CO2 laser improved scar scores, shortened crusting and lowered the rate of dark patches, though the certainty of that evidence ranges from very low to moderate (Zhou 2026).
- Fractional picosecond laser matched CO2 laser in Asian patients, and dark patches appeared only on the CO2 side (Sirithanabadeekul 2021).
What is still unknown
- How long results last. Most trials follow patients for months, and authors of recent trials ask for larger studies with longer follow-up (He 2026, Zhou 2026).
- The right settings for each skin type. The isotretinoin trial used one setting for every skin type (Taleb 2024), and the 2026 pooled analysis named skin type and scar type as open questions (Batool 2026).
Key papers
- Jordan 2001: Cochrane review that found no randomized trials of laser for acne scars, the starting point for the trials that followed.
- Xu 2018: review of fractional CO2 laser that set out how to plan sessions and when to add a second method.
- Gawdat 2014: PRP after CO2 laser improved results and shortened downtime.
- Cachafeiro 2016: microneedling matched nonablative laser with fewer dark patches.
- Sirithanabadeekul 2021: picosecond laser matched CO2 laser in Asian skin with fewer dark patches.
- Taleb 2024: laser during isotretinoin did better than waiting six months.
- Wu 2025: ranked every acne scar treatment against the others; combinations led.
- Li 2026: radiofrequency microneedling matched CO2 laser with faster recovery.
- Batool 2026: pooled comparison of CO2 laser and needling; similar results, more dark patches after laser.