What the research shows
What it does. Ablative fractional lasers (CO2 and Er:YAG) remove tiny columns of skin; nonablative ones heat the columns and leave the surface intact. Fractional CO2 treats deeper wrinkles, sun damage and scars with a shorter recovery than traditional CO2 resurfacing (Shamsaldeen 2011). In small studies, wrinkles, texture, looseness and blotchy color improved by roughly half on the face (Tierney 2012), the neck (Tierney 2009) and the eyelids (Kotlus 2010). Three nonablative sessions improved sun damage with only brief redness and swelling (Wanner 2007).
Which laser. Fractional CO2 and fractional Er:YAG did equally well on crow's feet in head-to-head trials (Karsai 2010, Robati 2017). A single session gives a real but limited change, and several may be needed for a full result (Karsai 2010).
Safety. After deep fractional CO2, about 1 treatment in 7 led to a side effect, mostly acne-like breakouts, cold sores or skin infection, and none scarred (Shamsaldeen 2011). Scarring is still possible: case reports describe raised scars on the neck and a pulled-down lower lid after aggressive settings or infection, and the authors advise lower energy on the eyelids and neck (Avram 2009, Fife 2009). Experts treat an active facial infection as a reason to wait and nearly all give antiviral and antibacterial medicine beforehand (Levy 2025).
Darker skin. Dark patches after treatment are the most common problem in darker skin. A strong steroid ointment for the first two days cut them from about 3 in 4 treated sides to about 2 in 5 (Cheyasak 2015), and sunscreen from the first day lowered pigment at one week (Wanitphakdeedecha 2014). In Chinese patients, dark patches affected more than half at one month and about 1 in 9 at six months (Chan 2010).
Precancerous spots. Fractional laser before photodynamic therapy cleared more rough sun spots (actinic keratoses) than photodynamic therapy alone, with fewer coming back (Togsverd-Bo 2012, Ko 2014).
Where surgeons disagree
- Darker skin risk. One protocol gave no dark patches after a single gentle treatment (Tan 2008); another found them common after one full treatment and questioned ablative fractional CO2 for Asian skin (Chan 2010).
- Melasma. A nonablative laser made melasma worse than prescription cream (Wind 2010); fractional CO2 combined with cream held its result better than either alone (Trelles 2010).
- Laser or needling for acne scars. Pooled studies found similar scar reduction; fractional CO2 succeeded slightly more often but caused dark patches about three times as often as microneedling (Batool 2026).
What is new
- Fractional laser can be done during a facelift: in one practice, adding it did not significantly raise complications (Sirmans 2025).
- An expert panel set out who should wait, how to prevent infection, and how to adjust settings for darker skin (Levy 2025).
What is still unknown
- How long results last and whether late side effects appear; long-term data on both are limited (Modena 2020).
- Whether healing aids work on the face. Platelet-rich plasma sped healing and reduced redness after fractional CO2, but the trial treated the inner arm (Na 2011).
- Whether the facelift finding holds in darker skin; nearly all patients in that study had fair skin (Sirmans 2025).
Key papers
- Wanner 2007: nonablative fractional treatment improved sun damage with little downtime.
- Fife 2009: cases of scarring that set safer settings for the neck and eyelids.
- Karsai 2010: fractional CO2 and Er:YAG matched on crow's feet.
- Shamsaldeen 2011: side effects of deep fractional CO2 across many treatments.
- Togsverd-Bo 2012: laser before photodynamic therapy clears more sun damage spots.
- Tierney 2012: how much fractional CO2 improves an aging face.
- Cheyasak 2015: two days of steroid ointment prevents dark patches in darker skin.
- Levy 2025: expert recommendations for fractional CO2.