The Efficacy and Safety of Synchronized Radiofrequency and High Intensity Facial Electrical Stimulation in Improving Facial Skin Laxity and Quality in Asians

ABSTRACT

Background

Noninvasive aesthetic procedures for facial rejuvenation are gaining popularity. Conventional treatments, such as radiofrequency (RF) and high‐intensity focused ultrasound (HIFU), primarily improve skin quality but do not address the deeper musculoaponeurotic structures that affect facial laxity. A novel approach that delivers synchronized RF with high intensity facial electrical stimulation (HIFES) thought to target both the skin and underlying musculoaponeurotic framework to effectively enhance facial laxity has been investigated.

Objective

To assess the long‐term efficacy and safety of combined synchronous RF and HIFES therapies in treating facial skin laxity among Asian subjects.

Methods

In this prospective, evaluator‐blinded study, 15 participants aged 40–65 years with mild to moderate facial skin laxity were enrolled. Each underwent four weekly treatments using a synchronized RF and HIFES system using noninvasive electrode applicators on the forehead and cheeks. Objective assessments included forehead and cheek lifting measurements using a 3D photographic system, eyebrow lifting measurement using ImageJ software, skin texture and melanin levels using Antera 3D®, and skin elasticity using Cutometer® MPA 580. Additionally, patients provided self‐assessments regarding their perceived level of improvement. Assessments were conducted at baseline, before the 3rd treatment, and at 1 month, 3 months, and 6 months after the last treatment.

Results

All participants completed the study. Significant improvements were observed in forehead and cheek lifting sustained at 6 months (p < 0.0001). A significant eyebrow lift of 1.39 mm was observed at 3 months (p = 0.0087), with a sustained lifting distance of 1.31 mm at 6 months (p = 0.0021). Skin firmness improved substantially (p < 0.0001), with R0 (skin firmness) increasing by 81.24% at 6 months. Skin texture improved notably in the crow's feet area (13.82% improvement at 3 months, p = 0.049). Melanin levels decreased significantly in the crow's feet and forehead regions. Treatment was well tolerated, with pain scores decreasing from 3.5 ± 1.8 to 1.6  ± 1.0 by the fourth session. No serious adverse events occurred.

Conclusions

Combined synchronous RF and HIFES therapy is a safe and effective Noninvasive method of improving facial skin laxity and quality in Asian subjects. Lasers Surg. Med. 00:00–00, 2024. © 2024 Wiley Periodicals LLC.

1. Introduction

Age‐related changes in the skin and the underlying fat, muscle, fascia, and bone contribute to the decrease in facial volume, development of wrinkles, and facial sagging. These changes have a significant impact on an individual's appearance, self‐esteem, and, ultimately, the quality of life [1, 2]. Thus, it's no surprise that aesthetic facial rejuvenation procedures continue to gain popularity among patients. To effectively improve facial aging, restoring the skin quality along with the integrity of the underlying interrelated structures such as the fascial system and muscles must be comprehensively addressed by any intervention, whether surgical or nonsurgical [3, 4].

Noninvasive treatments to address skin aging, like radiofrequency (RF), have been used to promote collagen remodeling through deep tissue heating with an overall wrinkle reduction and lifting effect [1, 5]. Another nonsurgical treatment is high‐intensity focused ultrasound (HIFU), which has been shown to reach the superficial musculoaponeurotic system (SMAS) to address skin laxity in the aging face [6]. However, the previously mentioned procedures do not alter the facial muscles that play a crucial role in natural skin mobility and laxity since permanent muscle contracture has been associated with shifting of the fat compartments and skin wrinkling [4, 7]. There is emerging evidence in the role of facial muscle strengthening exercises in achieving facial rejuvenation [8, 9]. Strengthening using neuromuscular electrical stimulation has also shown some promise in improving facial appearance and reducing facial sagging and wrinkles [10, 11]. Currently, the only definitive way to alter facial muscles is through a surgical lift procedure, where the skin and fat tissues are separated from the muscles, which are then repositioned to improve facial aging [12]. However, not all patients are good surgical candidates making energy‐based technologies viable nonsurgical alternatives for facial rejuvenation [13].

A recent development in the field of noninvasive facial rejuvenation is the introduction of synchronized radiofrequency (RF) with high intensity facial electrical stimulation (HIFES), offering a combined approach to address skin laxity and muscle, respectively, which are key components in facial aging [14, 15]. By generating electrical fields, HIFES technology selectively contracts the facial muscles which are essential for supporting the soft tissues and maintaining the facial structure. This dual‐technology system is designed to promote both dermal neocollagenesis and muscle toning simultaneously, creating a synergistic lighting and tightening effect to improve facial aging [14, 15, 16].

This prospective study aimed to objectively evaluate the long‐term efficacy and safety of combined synchronous radiofrequency (RF) and high intensity facial electrical stimulation (HIFES) therapies for the treatment of facial skin laxity in Asian subjects.

2. Methods

This prospective, pre‐post, evaluator‐blinded study was conducted at an academic skin laser center within a university tertiary hospital from September 2023 to September 2024. Fifteen participants aged 40–65 years, with mild to moderate bilateral skin laxity of the face and upper neck (Grade 2–4 on the Fasil Laxity Scale) [17] were enrolled.

The exclusion criteria used were as follows: patients with severe skin laxity or poor skin quality in the face and upper neck, patients with implanted electrical devices, or those with pre‐existing dermatologic or medical conditions that could interfere with trial participation.

Additionally, patients who received the following interventions in the target area within the last 6 months were excluded such as neuromodulator injection, facial fillers or biostimulators injection, ablative laser treatment, nonablative laser or light‐based treatments, monopolar radiofrequency, or microfocused ultrasound treatments. Furthermore, individuals with a history of face, neck, blepharoplasty, or rhytidectomy surgeries in the past 12 months were also excluded.

This study was approved by the Siriraj Institutional Review Board, Faculty of Medicine, Siriraj Hospital, Mahidol University, Thailand (Si 692/2023). Written informed consent was obtained from all participants before treatment initiation.

2.1. Intervention

Each of the 15 subjects (1 male and 14 females) underwent 4 weekly treatments on the face using a synchronized RF (radiofrequency) and HIFES (high intensity facial electrical stimulation) system delivered by a study device (EMFACE, BTL Industries Inc.). The treatment was administered using noninvasive, self‐adhesive electrode applicators placed simultaneously on the forehead and bilateral cheeks (Figure 1). Before each session, the treatment area was thoroughly cleansed of cosmetics and lotions. Jewelry and any prominent hairs were also cleared in the treatment area. The electrode applicators covered an area with a diameter of 15 cm, and each session lasted 20 minutes at a 100% power setting. No postprocedure care was provided. The study participants were asked to avoid the application of topical prescriptions containing whitening and/or smoothening effects such as alpha hydroxy acids, arbutin, licorice and retinoic acids.

FIGURE 1.

Electrode application landmarks. The applicator should cover the entire treatment area, avoiding placement over hair, eyebrows, or lips. (A) For the forehead, position the applicator centrally above the eyebrows, ensuring it follows the natural curve between the eyebrows, with no hair in the application zone. (B) For the cheek, place the applicator between the cheekbone and jawline, with the tail pointing toward the ear. Align the bottom edge along the mandibular line, with the front directed toward the corner of the mouth and the tail toward the tragus.

2.2. Evaluations

Both objective and subjective assessments were performed to evaluate the clinical improvement in facial lifting and skin quality. Any adverse effects were also noted. Evaluations were conducted at baseline, and then at before 3rd treatment, and 1, 3, and 6 months after the last synchronized RF and HIFES treatment. Standardized digital photographs, taken with consistent camera settings, lighting, and patient positioning, were captured at each visit to support the assessment.

Objective evaluations of facial skin laxity improvement were done by reporting measurements of forehead and cheek lift measured by a 3D photographic system (LifeViz® Mini camera, QuantifiCare S.A.). Eyebrow lifting was also measured using ImageJ software (National Institutes of Health).Additionally, volume measurements in the mid‐cheek, jawline, nasolabial fold, and tear trough areas using the same system were done. Skin quality measurements of facial wrinkles, pore volume, pigmentation and erythema levels were done using a 3D skin imaging device (Antera 3D®; Miravex Limited). Facial skin firmness was also measured using the Cutometer® MPA 580 (Courage & Khazaka).

Subjective assessment of facial laxity improvement was also done by the study participants reporting the percent improvement of their facial skin laxity at 6 months posttreatment compared to baseline. Adverse effects were monitored and recorded at all follow‐up visits. Additionally, patients rated their pain levels during treatment for each side using a visual analogue scale (VAS), ranging from 0 (no pain) to 10 (extreme pain).

2.3. Statistical Analyses

Demographic data were reported using descriptive analysis, including percentages, means, and standard deviations (SD). Paired variables measured at multiple time points were tested by repeated measures analysis of variance followed by a post hoc Tukey honestly significant difference test used to analyze the significance of observed changes. The significance level was set to α = 0.05 (5%). Statistical analysis was performed using IBM® SPSS® Version 26.0 (IBM Corp.).

3. Results

The study enrolled 15 participants (93.3% female, 6.7% male), aged 41–62 years (mean age 47.9 ± 4.9 years). Most participants had Fitzpatrick skin type IV (86.7%), with one participant each having skin types III and V.

3.1. Facial Lifting Measurement

Facial lifting was assessed using the LifeViz® Mini camera, with significant improvements observed in both forehead and cheek areas (Figures 2, 3, 4). The average forehead lifting increased from 1.447 mm before the third treatment to 2.140 mm 1 month after the final (4th) treatment (p < 0.0001), before decreasing to 0.673 mm at 6 months (p = 0.0006). Cheek lifting showed similar trends, with an initial increase from 1.240 mm before the third treatment to 1.373 mm 1 month after the final treatment (p < 0.0001), followed by a reduction to 0.580 mm at 6 months (p = 0.0635).

FIGURE 2.

A 47‐year‐old female with Fitzpatrick Skin Type IV. (A) Front view at baseline. (B) Front view at 6 months following four weekly treatments. (C) Right side view at baseline. (D) Right side view at 6 months following four weekly treatments.

FIGURE 3.

A 49‐year‐old female with Fitzpatrick Skin Type IV. (A) Front view at baseline. (B) Front view at 6 months following four weekly treatments. (C) Right side view at baseline. (D) Right side view at 6 months following four weekly treatments.

FIGURE 4.

Illustrations showing the facial lift of the same patient as in Figure 2, measured using a 3D photographic system. (A) Baseline. (B) Six months after four weekly treatments. Yellow and red arrows indicate an average lift of 1–2 mm compared to baseline.

Eyebrow lifting was also measured using ImageJ analysis, with a significant increase in the distance from the horizontal intercanthal line to the eyebrow (Figure 5). At baseline, the average distance was 21.56 mm, which increased to 22.95 mm at 3 months (p = 0.0087) and 22.87 mm at 6 months (p = 0.0021), demonstrating a significant lifting effect of 1.39 mm at 3 months and 1.31 mm at 6 months.

FIGURE 5.

Eyebrow elevation distance, defined as the vertical distance from the horizontal intercanthal line to the eyebrow. Mo, Month; Tx, Treatment. * Indicates a statistically significant elevation compared to baseline.

3.2. Volume Measurement

Volume measurements in the mid‐cheek, jawline, nasolabial fold, and tear trough areas showed some changes, but these were generally not statistically significant. The nasolabial fold volume increased slightly at 3 months (p = 0.0242), while the tear trough volume increased at 1 month (p = 0.0063) but returned to baseline by 6 months.

3.3. Skin Quality Analysis

3.3.1. Skin Wrinkles

Objective wrinkle measurements using Antera 3D® revealed varying degrees of wrinkle reduction across different facial regions. For crow's feet, a significant improvement in wrinkle severity was noted (p = 0.04), with a 12.39% increase in wrinkle reduction at 3 months and 10.70% at 6 months posttreatment (Figure 6). Forehead and cheek wrinkles also demonstrated some improvement, but these were not statistically significant (p = 0.1903 for forehead wrinkles and p = 0.2540 for cheek wrinkles).

FIGURE 6.

A 52‐year‐old female with Fitzpatrick Skin Type IV. (A) Crow's feet area at baseline. (B) The same area is 6 months after four weekly treatments. Note the smoothing effect on the crow's feet, the overall brightening of the skin tone, and the lightening of pigmented lesions following the treatments.

3.3.2. Pore Volume

Pore volume measurements did not show significant reductions, except for the forehead pore volume, which exhibited a significant decrease by 66.26% at 6 months (p = 0.0417). Pore volume changes in the crow's feet and cheek areas were not statistically significant (p = 0.1221 and p = 0.2596, respectively).

3.3.3. Skin Firmness

Skin firmness (R0), as measured by the Cutometer®, demonstrated statistically significant improvements from baseline at all follow‐up visits (p < 0.0001) (Figure 7). The R0 parameter improved by 45.68% before the third treatment and by 81.24% at the 6‐month follow‐up (p < 0.0001), indicating a substantial improvement in skin firmness over time.

FIGURE 7.

Cutometer measurement of skin firmness (R0). Mo, Month; Tx, Treatment. * Denotes a statistically significant improvement in R0 compared to baseline.

3.3.4. Pigmentation and Erythema Levels

Melanin levels, as measured by Antera 3D®, showed statistically significant improvements in crow's feet and forehead areas. Crow's feet melanin levels decreased by 3.05% at 6 months (p = 0.0257), while forehead melanin levels decreased by 3.53% (p = 0.0172). Cheek melanin levels also trended toward improvement, with a 3.54% reduction, although this was not statistically significant (p = 0.0556). Hemoglobin levels, which reflect skin erythema, did not show significant changes in any facial region.

3.4. Patient's Self‐Assessment

At the 6‐month follow‐up, 40% of the patients rated themselves as having more than 50% improvement in their facial contour, and 27% rated themselves as having over 75% improvement. None of the patients graded themselves as having no visible improvement.

3.5. Safety and Tolerability

Treatment was generally well tolerated, with a gradual decrease in reported pain scores. The mean pain score during the first treatment was 3.5 ± 1.8, which decreased to 1.6 ± 1.0 by the fourth session. No serious adverse events were reported during the study.

4. Discussion

Aesthetic procedures for correcting facial laxity, both surgical and nonsurgical, aim to reposition and restructure facial tissues [3, 10]. Age‐related changes in the skeleton, ligaments, muscles, adipose tissue, and skin occur at different rates but are interrelated [4]. Thus, addressing only one tissue type is insufficient for reversing facial aging. Comprehensive treatment approaches, targeting skin and deeper fascial and muscle layers, are necessary to achieve effective facial repositioning. This study investigated one such novel device with a combined RF and HIFES technology, presenting a promising noninvasive rejuvenation option.

This study demonstrated that the synchronized RF and HIFES treatment can effectively lift the forehead, eyebrows and cheeks. Quantitative measurements showed an increase in forehead lifting from 1.447 mm before the third treatment to 2.140 mm 1 month after the final treatment (p < 0.0001), which, although decreased to 0.673 mm at 6 months, remained significant (p = 0.0006). Similarly, cheek lifting improved initially and maintained a trend towards significance at 6 months. Eyebrow lifting, assessed via ImageJ analysis, also exhibited a significant increase, indicating a sustained lifting effect up to 6 months posttreatment. A previous study done by Kinney and Boyd also reported sustained lifting of the eyebrow and cheek by an average of 23% using the same novel device combining RF and HIFES [14]. The degree of lifting was slightly higher in the study by Kinney and Boyd [14], which consisted of Caucasian patients, in contrast to the current study, which only enrolled Thai patients. Although further comparative studies are necessary to confirm this trend, these findings suggest that skin characteristics and anatomical variations among different ethnicities should be considered when administering this treatment. This consideration has potential implications for modifying treatment protocols and designing treatment pads specifically tailored to Asian patients, thereby optimizing the efficacy of this novel device for this population.

While RF alone has been shown to improve skin laxity, the addition of HIFES in this novel device can also explain the significant lifting effect seen in this study. The strategic positioning of the applicators ensures that the HIFES technology induces supramaximal contractions of the facial elevator muscles, such as the frontalis, zygomaticus major, zygomaticus minor and risorius while avoiding the facial depressor muscles such as the glabella and masseter that can worsen the rhytids [15]. An electromyography (EMG) study on the facial muscles noted decreased frontalis activity (although not statistically significant) and decreased zygomaticus major in older individuals [18]. Strengthening of these muscles via the HIFES technology can explain the sustained lifting response seen even at 6 months in the forehead and eyebrow with the cheek lift trending towards significance. This suggests that increasing the muscle mass of the frontalis is important to lift the forehead and eyebrow. A similar conjecture can be said for the zygomaticus major, zygomaticus minor and risorius being crucial in lifting the cheek. However, it is also important to note that the peak lifting effect on all the treated areas was achieved 1 month after the 4 weekly sessions, suggesting that the increase in muscle tone dissipates over time. In porcine histological studies, it was demonstrated that muscle hypertrophy and an increase in muscle stem cells occur 1 month after 3 weekly sessions of RF with HIFES [16]. Another porcine histological muscle study noted a peak increase of facial muscle mass at 19.2% at 2 months post treatment [1]. This suggests that, like any other skeletal muscle in the body, facial muscles also need consistent workload to maintain the muscle tone and to avoid atrophy. The mechanical stimulation, in addition to heating produced by the RF, can also potentially induce remodeling in the fascial layer, specifically in the SMAS, further contributing to the lifting effect seen [15, 19]. In porcine studies, facial muscle temperature measurements exceeded 39°C in the first 2 min, which stabilized to 39.5°C by the third minute of treatment [1].

Volume measurements in the mid‐cheek, jawline, nasolabial fold, and tear trough areas showed some variations, though most were not statistically significant, aside from slight increases at specific intervals. This suggests that while the treatment effectively produces lifting, it may not significantly alter facial volume. A previous study done by Kinney and Boyd also reported modest increases on average volume for the mid‐lower face at 2.53 ± 2.1 mL on the 3^‐month follow‐up period [14]. This is an important consideration since some patients prefer a subtle volumizing effect since excessive volume changes could lead to unnatural facial appearances. The primary effect of the combined RF and HIFES therapy appears to be on muscle toning and skin lifting rather than volumizing depressed areas due to facial aging. Soft tissue fillers remain as the primary nonsurgical method that can address volume loss [20].

Aside from the lifting effect, the combined treatment also led to an overall improvement in skin texture. There were significant improvements in the crow's feet wrinkles, forehead pore volume and skin firmness in all treated areas at the 6‐month follow‐up period. Skin wrinkle improvements, particularly in the crow's feet area, approached statistical significance (p = 0.049), indicating a positive trend towards smoother skin. While forehead and cheek textures improved, they did not reach statistical significance, possibly due to the small sample size or variations in individual responses. The significant reduction in forehead pore volume by 66.26% at 6 months (p = 0.0417) further supports the skin‐smoothening effects of the treatment.

Measurements using the Cutometer® revealed substantial enhancements in skin firmness, with improvements persisting and even increasing up to 6 months posttreatment (p < 0.0001). These findings can be explained by the RF component of the device being able to heat up the dermis to 40°C in the first 2 min of treatment, maintaining up to 42.5°C for the remainder of the session [1]. This disrupts the collagen fibers, which stimulates fibroblast activity leading to an increase in neocollagenesis and neoelastogenesis [1]. Human histological studies after combined RF and HIFES treatment noted an increase in collagen and elastin formation at the 3‐month follow‐up period by 30% and 102.8%, respectively [21]. Prior studies using the same novel device reflected this clinically with a reported improvement in skin textures using Fitzpatrick Wrinkle and Elastosis Scale, Global Aesthetic Index Score and various imaging software [14, 21, 22].

This study also demonstrated significant reductions in the pigmentation of the crow's feet and forehead areas, with a near‐significant reduction in the cheeks. The decrease in melanin levels may be attributed to the thermal effects of RF energy, which can influence melanocyte activity and lead to a more even skin tone [23]. There are various reported mechanisms by which RF can improve or decrease melanin synthesis, such as promoting melanosome autophagy and increasing HSP70, a heat shock protein, that leads to tyrosinase inhibition [24, 25]. However, skin erythema, measured by hemoglobin levels, did not show significant changes indicating that the treatment does not improve the skin's vascular components.

Safety and tolerability were also demonstrated in this study, with no serious adverse events recorded and the participants reporting decreasing pain scores over successive treatments. The mean pain score decreased from 3.5 ± 1.8 during the first treatment to 1.6 ± 1.0 by the fourth session, indicating increased patient comfort with the procedure over time. This aligns with previous studies reporting the safety of RF and HIFES treatments, emphasizing their suitability for patients seeking noninvasive rejuvenation options with minimal downtime [14, 22].

Despite the promising results, the study has limitations that should be acknowledged. The small sample size of 15 participants may limit the generalizability of the findings. Additionally, the study population consisted predominantly of females (93.3%) and individuals with Fitzpatrick skin type IV (86.7%), which may not represent the broader population. Future studies with larger, more diverse cohorts are necessary to validate these results. Furthermore, the absence of a control group makes it difficult to attribute the observed effects solely to the treatment without considering possible placebo effects or natural aging variations.

Another limitation is the relatively short follow‐up period of 6 months. While significant improvements were observed at this time point, longer‐term studies are needed to assess the durability of the treatment effects. It would also be beneficial to compare the combined RF and HIFES therapy directly with other established noninvasive treatments, such as HIFU or traditional RF alone, to determine the relative efficacy [6, 26].

In conclusion, combined RF and HIFES therapy demonstrated significant efficacy in improving facial lifting and skin quality, increasing skin firmness while reducing wrinkles, pore volume and pigmentation, in Asian subjects with mild to moderate facial skin laxity with minimal adverse events. These findings suggest that this dual‐modality novel treatment is a promising noninvasive option for facial rejuvenation since it targets various components implicated in facial aging, the skin along with the deeper fascial and muscle layers. With RF, it promotes neocollagenesis and neoelastogenesis in the dermis while the HIFES component induces enhanced muscle tone and the regeneration of the underlying connective tissue framework. Further research with larger, more diverse populations and longer follow‐up periods is warranted to confirm these results and to explore the potential of this therapy as a standard treatment for facial skin laxity.

Conflicts of Interest

The authors declare no conflicts of interest.