One trial answers most of this question, and it is a good one. Li and colleagues (2026) ran a randomised, evaluator-blinded, split-face study in atrophic acne scars: 30 people completed it, each with RF microneedling on one side of the face and fractional CO2 on the other, three sessions eight weeks apart. The ECCA score - a standard acne-scar severity score, where a lower number means less scarring - fell from 54.73 to 30.53 on the RF microneedling side and from 53.67 to 31.03 on the CO2 side. There was no significant difference between the two treatments.
Where they did differ was the recovery. In those same patients, the RF microneedling side had shorter redness, pain, swelling and scab duration, and fewer episodes of post-inflammatory hyperpigmentation - the brown marks that can follow skin injury.
The mechanisms are genuinely different. CO2 removes tissue; RF microneedling does not. A fractional CO2 laser vaporises a grid of tiny columns of skin from the surface down. RF microneedling puts insulated needles through the surface and coagulates tissue at a depth the operator chooses, largely sparing the top layer. That is the real trade-off: CO2 resurfaces, RF heats from within.
One caveat that belongs on every Morpheus8 page: the trial above used RF microneedling, not Morpheus8. Almost no published study used Morpheus8 specifically. The literature was generated on other machines - Lutronic, Jeisys, Pollogen, Lumenis and unnamed devices. People searching for Morpheus8 are usually being shown someone else's data.
1 MHz bipolar radiofrequency. Per InMode's manual the pins are coated except the last 0.5 mm, so energy comes off the tip and the surface is largely spared.
Each column is removed, and the untreated skin around it drives the healing.
InMode's manual lists 1 to 4 mm for the 12-pin Prime tip, 1 to 7 mm for the standard 24-pin, 2 to 7 mm for the Body tip, and a fixed 0.5 mm resurfacing tip. The deepest figure in any FDA summary is 7.0 mm.
Acne scars, wrinkles, laxity, cellulite, stretch marks and double chin do not appear in any Morpheus8 clearance.
Acne scars are the best-evidenced use of the RF microneedling class - a 2025 systematic review of 16 studies and 481 patients concluded it is "likely" effective as a standalone treatment.
CO2 remains the stronger tool when the goal is to genuinely resurface the skin.
One 40-patient series reported redness in 100% and swelling in 30%; another put downtime at three to four days. Skin barrier measurements return to baseline by about day seven.
Prolonged redness is a recognised feature of ablative resurfacing.
In the one stretch-mark study that measured it, the RF side was significantly more painful during treatment than the CO2 side (5.35 vs 2.35 out of 10).
InMode's manual says one to six treatments, typically three to five, every three to six weeks.
This is where the two genuinely part company.
CO2 carries more pigment risk, and RF microneedling carries less. In the split-face trial, the CO2 side produced more post-inflammatory hyperpigmentation than the RF side in the same person. A separate stretch-mark study found brown marks on 6 of 10 CO2-treated sides versus 4 of 10 RF-treated sides, mostly settling by three months.
Ablative CO2 also carries a risk that runs the other way: loss of pigment in treated skin. Post-inflammatory hypopigmentation appears in published complication series from energy-device procedures alongside scarring and lasting redness (Murray 2024). Those series are small and give no figure for how often it happens or how long it lasts, but it is the risk that makes CO2 a more careful decision in deeper skin tones.
RF microneedling is not risk-free on pigment either. In the FDA's postmarket reporting database, pigmentary change was the second most common category of reported RF microneedling problem: 41 of 224 reported events between 2013 and 2025. That is a share of the reports that were filed, not a rate per patient treated - the database has no denominator, so it cannot tell you your odds. And note the on-label limit: above 62 mJ per pin, Morpheus8 is restricted to Fitzpatrick skin types I to IV.
Two limits are worth knowing before you spend money.
The evidence runs out at six months. In essentially all controlled RF microneedling studies, the longest properly measured follow-up after the final treatment is six months. The clinic line that results last one to three years has no published source.
The studies were mostly not run on Morpheus8. The best comparative data, including the trial at the top of this page, came from other RF microneedling devices. That does not make Morpheus8 worse. It does mean the numbers are borrowed.
If you get cold sores, say so when you book, not on the day. Antiviral cover is started in advance, and it is routine before ablative CO2 resurfacing, where reactivation of the cold sore virus is well documented.
The same precaution is commonly used before RF microneedling. Be aware that there is no published data on cold sore reactivation after RF microneedling specifically - the practice was carried across from laser resurfacing, which is reasonable but is not the same as evidence.