A 2021 critical review of the RF microneedling literature counted five higher-quality studies of stretch marks. The best characterised is Al-Muriesh 2020.
The design was sound for its size. Fourteen people enrolled and ten finished. Each person had non-insulated RF microneedling on the right side of the abdomen and fractional CO2 laser on the left, three sessions, assessed by dermoscopy and standardised photography two months after the final treatment. Because both treatments were on the same person, the comparison is a fair one.
The primary aesthetic result was negative. The Global Aesthetic Improvement Scale did not reach statistical significance for either treatment — p=0.18 when the investigators scored it, p=0.17 when the patients did. That is the sentence that matters most, and it is missing from almost every clinic page on this subject.
A secondary measurement was positive. The width of the stretch marks decreased between 5% and 32% on the RF side and between 6% and 31% on the CO2 side, with no significant difference between them. So the marks did get narrower on measurement, even though the overall look did not change enough to register as a significant improvement.
Both things are true. Neither should be dropped.
Pain. RF microneedling was significantly more painful than the CO2 laser in the same patients: 5.35 out of 10 versus 2.35, p=0.0016.
Pigment. Darkening after treatment occurred on 4 of the 10 RF-treated sides and 6 of the 10 CO2 sides. Most resolved by the three-month follow-up. Abdominal skin and higher energy settings are part of why this number is much higher than the pigment rates reported for facial treatment, where one 40-patient acne-scar study found post-treatment darkening in 5% of people.
This is not a case of one treatment failing where others succeed. Striae are scars in the dermis, and no method reliably erases them.
The published evidence for this device class is one split-body study in ten people who completed it, and it did not separate its results by the age or colour of the stretch marks. Anything you read about newer marks responding better than older ones is not something this literature has tested.
Read the RF microneedling result in that context. It is a weak result for a hard problem, not a uniquely poor treatment.
No clearance for Morpheus8, or for any device in this class, mentions striae or stretch marks.
Morpheus8's clearances are for electrocoagulation and haemostasis (December 2019) and, from the 2023 update, coagulation or contraction of soft tissue. Those are generic electrosurgical terms. No cosmetic use is named — not stretch marks, not wrinkles, not acne scars, not cellulite.
Using it for stretch marks is therefore off-label. Off-label use is legal and routine in aesthetic medicine, and it is not a criticism in itself. But two related points are worth keeping straight: a 510(k) clearance means the device is similar enough to an earlier device, not that it was shown to work; and a clinic advertising an RF microneedling device as "FDA cleared for stretch marks" is stating something that appears in no RF microneedling clearance. Striae do appear in one FDA clearance in aesthetics — the Palomar Lux1540 non-ablative fractional laser, cleared in 2009 for "treatment of melasma and striae" — but that is a different device on a different technology, and it is not what is in the room when you are offered Morpheus8.
Readers searching "Morpheus8 stretch marks" should know that the study above did not use Morpheus8. It used a non-insulated microneedle RF device.
This is true across the field. Almost no published RF microneedling trial used Morpheus8 — the literature comes from Lutronic, Jeisys, Pollogen, Lumenis and unnamed devices. A PubMed search for Morpheus8 returns 16 records, and no randomised controlled trial of the device was found. So the evidence being cited for Morpheus8 was mostly generated on other machines with different needle designs and energy settings.
If you are considering this, some fair questions:
A provider who tells you this is an established, evidence-backed treatment for stretch marks is overstating the literature.
If you get cold sores, tell the clinic when you book rather than on the day. Antiviral medicine is started in advance. There is no RF microneedling-specific data on this — the practice comes from laser resurfacing, where cold sore reactivation is well documented.
Sun protection is the best-supported aftercare instruction here, because of the documented pigment risk on treated body skin.