How does RF microneedling work in the skin?

Heat from electrical current

A laser needs a chromophore: a substance that absorbs the light. Radiofrequency does not: it is an alternating current that flows through the tissue. The tissue's resistance, its impedance, converts that current into heat ^[1]. How the current spreads beneath an electrode placed on the skin is explained on the monopolar RF page.

In RF microneedling, the needles themselves are the electrodes. They pass through the epidermis and deliver the energy directly into the dermis ^[1]. The heat is therefore generated at depth, around the needle, and not at the skin surface. A treatment thus leaves two kinds of tiny wounds: the needle punctures and, deeper down, the coagulation zones. According to a review article, it is precisely this heat that gives RF microneedling an advantage over microneedling without RF, especially for tightening; the article presents no data of its own ^[2].

Bipolar or monopolar

Where the heat is generated also depends on where the current flows. In bipolar RF microneedling, the current flows between the needles of the same tip, the disposable cartridge that holds the needles. Each needle is an electrode, and the current stays in the small area of skin beneath the tip. In an animal study, a separate coagulation zone formed in the dermis around each needle ^[3].

In monopolar RF, the current flows from one active electrode through the body to a neutral electrode: an adhesive pad placed elsewhere on the body ^[1][3]. Some RF microneedling systems also have a monopolar setting ^[1].

Genius works in bipolar mode, according to its 510(k) summaries at the US FDA. It delivers its energy at 460 kHz through tips that include one with 7 × 7 bipolar microneedles ^[4][5]. XERF, the other RF device we supply, works in monopolar mode and without needles: a cooled electrode on the skin heats a larger volume of tissue beneath it. That is a different treatment, aimed mainly at tightening. You can read more about it on the monopolar RF page.

Insulated and non-insulated needles

Where along the needle the current enters the tissue matters too. An insulated needle is shielded along almost its entire length; only the tip conducts. The energy is then released at the chosen depth, and the channel through the epidermis is spared ^[1]. With a non-insulated needle, the whole needle acts as the electrode ^[1]. In an animal study, the epidermis was largely spared with these needles as well, and the coagulation zones lay mainly in the dermis ^[3]. We found no clinical study directly comparing the two types of needle.

Genius uses insulated needles. According to the FDA summary, the tissue coagulates around the non-insulated part of the needle ^[4]; with insulated needles, that is the tip ^[1].

Depth and layer

Because the heat starts at the needle tip, the needle depth determines which layer you treat. According to a review article, the target is usually the reticular dermis, and the depth depends on skin thickness in the treatment area: shallower around the mouth than on the forehead ^[2]. Working in several passes at different depths places coagulation zones in layers one above the other ^[1]. In histological studies, greater needle depth and a longer pulse produced larger coagulation zones ^[1].

On the 2018 version of Genius, the needle depth is adjustable from 0.5 to 3.5 mm ^[4]; the version the FDA cleared in 2026 goes to 4 mm ^[5].

Energy and impedance

The energy per needle also matters, although it is linked to the pulse duration. In a study on ex vivo pig skin, the coagulation volume around the needle grew as the energy per needle rose. The device, a Genius, automatically lengthened the pulse at higher energies. One of the authors was technical director at the time at Lutronic; two others received speaker fees from the company ^[6].

How much heat a pulse actually produces also depends on the impedance of the tissue. It differs between the layers of the skin, between people and between sites on the body. It also changes during the pulse: warm tissue conducts better until it coagulates, but as soon as the water vaporises, the impedance rises sharply ^[1]. Newer RF microneedling devices therefore measure impedance during treatment ^[1]. As early as 2009, researchers described a needle-based device that measured temperature and impedance in real time to control energy delivery ^[7].

According to Cynosure Lutronic, Genius measures impedance and adjusts energy delivery about 500 times per second ^[8]. We are not aware of clinical studies comparing devices with and without such feedback. With a second pulse at the same spot and depth, the energy delivered is less predictable, because the impedance has changed ^[1]. The treatment protocols set out how to sequence passes and depths.

How the skin responds

After treatment, wound healing begins in the dermis. In biopsies after bipolar fractional RF with needles, the coagulation zones were still visible after four weeks and had been replaced by new tissue after ten weeks, with more collagen and elastin ^[9]. Clinically, too, the skin improves gradually, and the effect can still increase six months after treatment ^[10].

Dark skin

Here the main concern is the risk of pigmentary change. RF does not target melanin, and in RF microneedling the energy is released beneath the epidermis. RF microneedling is therefore regarded as a technique with a lower risk of pigmentary change in dark skin ^[19]. A systematic review of 35 studies of RF and RF microneedling in skin types III to VI found temporary post-inflammatory hyperpigmentation (PIH) in seven studies, mild, longer-lasting hyperpigmentation in one study and permanent scarring in one study. The authors describe the risk as low ^[19]. In comparative studies, PIH occurred less often than after fractional CO₂ ^[17][13]. PIH does occur after RF microneedling too, usually transiently ^[20].

The studies with Genius itself mainly involved patients with skin types II and III; skin types V and VI were not included. Even in that group, one patient developed temporary PIH after the first RF microneedling treatment ^[18]. Cynosure Lutronic describes Genius as safe for all skin types ^[8]. We are not aware of data on Genius in skin types V and VI.

Recovery and pain

Apart from the pigment risk, recovery is also a factor. Expect redness and swelling after treatment. In the systematic reviews, side effects were mostly mild and short-lived ^[21][20]. In a study with Genius, redness and swelling resolved within a few days ^[18]. Cynosure Lutronic cites 24 to 36 hours for mild redness and swelling, and up to a week for full recovery ^[8]. In a randomised comparison with fractional CO₂, redness, swelling and crusting were shorter-lived ^[13].

The treatment is painful. In one randomised comparison, RF microneedling was more painful during treatment than fractional CO₂ ^[12]; in the other, pain after RF microneedling was shorter-lived ^[13]. In a study with Genius, patients received a topical anaesthetic beforehand and still rated the pain at 5.6 out of 10 on average ^[18]. Discuss pain management with your patient beforehand.

In the same study, four of the 27 patients treated with RF microneedling alone developed perioral dermatitis; one of them also had a bruise at the orbital rim ^[18]. A scoping review points to a longer-term risk: RF microneedling can cause fibrosis and adhesions between tissue layers, which can complicate a later facelift. The authors recommend discussing this with patients who may consider a facelift in the future ^[22].

The studies with Genius excluded, among others, patients with a tendency to excessive scarring, with scars or lesions in the treatment area, or with recent surgery or injectable treatment ^[18]. The full list of contraindications is in the device manual.

Alongside other technologies

RF microneedling invites comparison with monopolar RF and with fractional lasers. Monopolar RF, which we offer as the XERF, heats a larger volume of tissue beneath the electrode without needles and reaches deeper than bipolar RF on the skin. RF microneedling combines tiny wounds from the needles with heat in the dermis ^[23]. In our view, this makes RF microneedling suitable for scars and texture as well, whereas monopolar RF is aimed mainly at tightening. We are not aware of direct comparisons between the two.

The fractional lasers in question are ablative CO₂ (eCO2 3D) and erbium, and non-ablative lasers at 1540–1550 nm (Mosaic 3D) and with thulium (LaseMD Ultra). A systematic review found four split-face studies in acne scars with a fractional laser as comparator or in combination. RF microneedling improved the scars, with shorter recovery than ablative CO₂ ^[24]. RF microneedling is also combined with a laser, for example with thulium when pigment is present as well ^[18].

RF microneedling has also been studied in active acne, melasma, rosacea and excessive sweating ^[10][20]. Those applications fall outside the scope of this page.

Research with Genius

Much has been published on RF microneedling, and there are several systematic reviews ^{[10][11][21][20]}. They are positive about efficacy and safety, but also point to weaknesses. Many studies are small and not randomised, they use different devices and settings, and they often report those settings incompletely ^[11][20]. Two of the most recent reviews are by authors who work or speak for Jeisys, a manufacturer of RF microneedling devices ^[21][20].

The clinical research with Genius comes mainly from one group in Hamburg ^[14][6][18]. According to the FDA, Genius is based on the same principle as its predecessor Infini, and both devices produced comparable coagulation zones in an animal study ^[4]; studies with the Infini therefore also shed light on the technology in Genius.

In summary: RF microneedling improves acne scars and texture. For scars, the effect in comparative studies comes close to that of fractional lasers; recovery is shorter than after ablative CO₂. For laxity, an effect is measurable, but it varies greatly between patients. In dark skin, the risk of pigmentary change is lower than with ablative CO₂, although PIH does occur after RF microneedling too.