A 2026 prospective randomized split-face trial treated one cheek with radiofrequency microneedling and the other cheek with fractional carbon-dioxide laser for facial atrophic acne scars, which are depressed scars that sit below surrounding skin, according to the U.S. National Library of Medicine / PubMed in the PubMed trial record.
Both sides improved, but the radiofrequency side had shorter redness, pain, swelling and scab shedding plus fewer dark marks after inflammation and higher safety satisfaction. Atrophic scars include icepick, boxcar and rolling types. The trial design matters because each person served as their own comparison, with one device on each cheek.
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Table of Contents
- What did each cheek receive?
- How did pain and downtime differ?
- Who needs extra pigment caution?
- What else was tested for repair?
What did each cheek receive?
One cheek received radiofrequency microneedling, which delivers heat through tiny needles without removing surface skin. The other cheek received fractional carbon-dioxide laser, which creates narrow columns of ablative injury to trigger repair.
Both approaches aim to remodel scar tissue and build collagen. The U.S. National Library of Medicine / PubMed reports improvement on both sides in the 2026 trial.
How did pain and downtime differ?
The radiofrequency side cleared faster across four measures: redness, pain, swelling and scab-detachment time. It also logged fewer post-inflammatory hyperpigmentation events, meaning brown marks after healing.
A pooled analysis of 8 randomized trials with 249 patients adds context, reported in the ResearchGate study record in the pooled analysis of eight randomized trials. Fractional CO2 laser gave greater scar improvement by a mean difference of 0.31, but pain scores were higher by a mean difference of 2.14 with longer redness.
Who needs extra pigment caution?
People with Fitzpatrick types III-VI face higher pigment-change risk after laser. Key split-face comparisons are exploratory, small-sample and often single-treatment, so averages may not predict prolonged darkening in darker skin.
Experts still do not treat darker skin as a bar to ablative resurfacing, according to the Medscape expert-consensus report in the Medscape expert-consensus report. The same report advises sun protection, cooling and experienced settings:.
- ask about Fitzpatrick type and prior dark marks
- confirm sun protection plan before and after
- confirm cooling and conservative settings for darker skin
What else was tested for repair?
A randomized double-blind split-face study in Asian patients with Fitzpatrick types III-V and moderate-to-severe scars tested fractional microneedle radiofrequency plus transdermal poly-L-lactic acid through microchannels versus radiofrequency alone. Springer Nature / Dermatology and Therapy found the combination safe and effective.
Adverse effects were mild, transient and self-limiting, including mild redness in 4.2% after each session and acne flare in 4.2% resolving within days to one month. A separate 2026 randomized investigator-blinded split-face trial in China tested topical vitamin C plus vitamin E plus ferulic-acid serum as an adjunct to ablative CO2 laser for postoperative repair, according to Wiley / Journal of Cosmetic Dermatology.
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