What the research shows
The first CO2 lasers of the 1980s scarred too often. Pulsed and scanned lasers in the 1990s made full resurfacing controllable, and fractional lasers later traded some effect for a faster recovery. Neither fractional nor gentler non-ablative lasers match the results of full resurfacing, but they became more popular because their risks are lower (Alexiades-Armenakas 2008).
Full resurfacing works on wrinkles around the mouth and eyes: the finest lines disappeared, deeper ones improved, and loose skin tightened as the heat shrank collagen (Fitzpatrick 1996). Results held at a year with some return of lines, most around the mouth, where movement creates them, and least on the cheeks (Schwartz 1999). Improvement lasted through about two years of follow-up, and the most common late side effect was skin lighter than the untreated skin nearby (Manuskiatti 1999a).
Recovery is long. In a large series, every patient had redness, lasting about four and a half months on average; dark patches appeared in over a third, more often in darker skin; cold sores flared in about 1 in 14; scarring was under 1 in 100 (Nanni 1998). Antibiotic pills prevented bacterial infection and antifungal pills prevented yeast infection, while antibiotic ointment in the nose did not help. Infections can be subtle and appear in the second week (Manuskiatti 1999b).
On the lower eyelids, CO2 resurfacing alone or with eyelid surgery left most patients very satisfied, with no lasting scar or turned-out lid (Kim 2021). Removing lower lid fat from inside the lid can leave the skin more wrinkled, and adding laser corrected that (Carter 2001).
Darker skin darkens easily after laser. In Asian patients given fractional CO2, about half had dark patches at one month and about 1 in 10 at six months (Chan 2010). In Asian skin, two days of a strong steroid ointment after treatment cut that risk (Cheyasak 2015).
Where surgeons disagree
- CO2 or erbium. In a split-face study, CO2 improved wrinkles more but left lighter patches far more often and redness for longer (Khatri 1999); a review agreed on both points (Chen 2017). Fractional versions of the two lasers reduced wrinkles equally, with more discomfort after CO2 (Robati 2017).
- Laser or peel for the upper lip. A deep phenol peel smoothed upper lip lines more than CO2 laser on the other side of the same lip (Chew 1999).
- How safe fractional is. Fractional lasers were adopted for lower risk (Alexiades-Armenakas 2008), yet thickened scars after fractional CO2 on the neck show the risk remains, and treating the neck calls for caution (Avram 2009).
What is new
- An expert panel on fractional CO2 agreed on routine antibacterial and antiviral prevention and on adjusted settings for darker skin types, and reported that the skin heals over within one to six weeks (Levy 2025).
- One low-energy fractional session reduced the number and depth of wrinkles around the eyes and increased collagen in the skin (Jordão 2022).
What is still unknown
- How full resurfacing holds past two years. The long-term data come from 1990s series (Manuskiatti 1999a, Schwartz 1999).
- The safest settings for darker skin. The studies are small (Chan 2010), and the expert panel noted its own small size (Levy 2025).
Key papers
- Fitzpatrick 1996: showed pulsed CO2 smooths wrinkles around the mouth and eyes and tightens skin.
- Nanni 1998: the complication profile of full CO2 resurfacing.
- Khatri 1999: CO2 against erbium on the same faces.
- Manuskiatti 1999a: results held for about two years.
- Schwartz 1999: which areas of the face hold their result best.
- Alexiades-Armenakas 2008: how ablative, fractional and non-ablative lasers compare.
- Cheyasak 2015: a short steroid ointment course reduced dark patches in Asian skin.
- Kim 2021: lower eyelid CO2 resurfacing with high satisfaction and few lasting problems.