Body Shaping and Skin Appearance Improvement in the Abdomen and Flanks by Radiofrequency Technology

ABSTRACT

Objective

This study aims to assess the safety and effectiveness of the Symmed radiofrequency (RF)‐based device (Termosalud Inc., Gijón, Spain) in body contouring and skin appearance improvement treatments for abdomen/flanks.

Material and Methods

Eight sessions of Symmed RF were performed in 15 volunteers' abdomen/flanks. Sessions were conducted every 72/96 h. To evaluate the efficacy and safety of the device, photographs, body contours, and ultrasound scans of dermal echogenicity, and adipose tissue thickness were taken at baseline and after the treatments. Additionally, a blind evaluation of the photographic results was conducted. Data regarding the satisfaction level of the participants was also obtained through a customized survey.

Results

At the follow‐up visit, significant reductions of 2% in body circumference and 9% in fat thickness were detected in the abdomen/flanks. These effects were accompanied by a significant 12% increase in dermal echogenicity, related to skin collagen content and organization. Furthermore, the blind evaluation of the photographic results revealed an overall visual improvement. A high satisfaction level was reported by the participants and no severe adverse events were detected.

Conclusion

Symmed treatment is a noninvasive procedure treating skin laxity and reducing abdomen/flanks circumferences safely and effectively.

Clinical Trial Registration

This clinical trial is not registered in a publicly accessible database, and no clinical trial registration number is available. At the time of the investigation, the intended use for fat reduction through radiofrequency was not classified as a medical application under European legislation (COUNCIL DIRECTIVE 93/42/EEC). In accordance with Spanish and European regulations, only clinical trials evaluating medical devices are required to be registered.

1. Introduction and Objective

The field of nonsurgical fat reduction has significantly advanced in recent years, marked by the development of innovative energy‐based devices. These new technologies have undergone rigorous clinical testing, demonstrating both their safety and efficacy. As a result, these treatments have become increasingly popular among patients seeking body contouring solutions without the need for invasive surgery.

Patients pursuing nonsurgical fat reduction and skin tightening often have several primary concerns. Non‐invasiveness is at the top of their list, followed by procedures that offer minimal or no downtime. Additionally, the level of discomfort or pain during and after the procedure is a critical factor. In this scenario, noninvasive radiofrequency (RF) devices have emerged as a promising approach for reducing fat, improving the appearance of cellulite, and tightening skin. These devices use RF energy to target and heat the subcutaneous fat layer, leading to a reduction in fat volume and improved body contours. Compared to traditional surgical methods, these noninvasive techniques offer a lower‐risk alternative with minimal downtime and recovery period.

Numerous studies have demonstrated the efficacy of noninvasive RF devices in reducing fat and improving the appearance of skin [1]. The mechanism of action involves both electrical and thermal stimulation of the dermal and subcutaneous tissues. In the dermal layer, RF energy activates fibroblasts, increasing the production of extracellular matrix fibers (mainly collagen and elastin) and improving the vascularization of the tissue, thus enhancing the supply of oxygen and nutrients [2, 3]. Beyond skin tightening, some RF devices effectively induce lipolysis and the breakdown of fat cells (adipocytes), making them valuable for body contouring and cellulite reduction [4, 5, 6]. The high impedance of subcutaneous adipose tissue generates significant energy and heat when exposed to RF waves. This volumetric heating causes irreversible damage to fat cells, leading to their breakdown and removal from the body [7, 8, 9]. Consequently, the basal metabolic rate of triglyceride breakdown into glycerol and free fatty acids in the treated areas is increased, promoting further fat loss [10, 11].

Overall, RF bulk heating skin tightening devices offer a versatile and effective solution for both skin rejuvenation and body contouring. Their ability to reduce wrinkles, tighten lax skin, reduce fat tissue thickness, and minimize cellulite—all with minimal discomfort and no downtime—makes them an attractive option for those seeking noninvasive cosmetic enhancements.

Symmed is an innovative monopolar RF‐based device developed by Termosalud Inc. that offers a balanced combination of fat reduction, skin tightening, and overall body contouring without the drawbacks associated with more invasive procedures. For this purpose, the device can work in resistive or capacitive modes by applying a high‐frequency and low‐impedance current with electrodes adapted in shape and size to the needs of each treatment area. Symmed allows to adjust the delivered energy (up to 200 W) and the treatment duration. Additionally, to ensure treatments safety and potentiate the results, it incorporates a handpiece temperature sensor, as well as an automatic regulation program and a thermal optimization system. This study was conducted to evaluate the effectiveness and safety of the RF‐based device Symmed for treating noninvasive corporal skin laxity and fat accumulation as an alternative to traditional methods.

2. Materials and Methods

2.1. Participants

The study was approved by the Research Ethics Committee of the Principality of Asturias. Fifteen healthy volunteers, women (n = 14) and men (n = 1), from 30 to 62 years old, and Fitzpatrick skin type II to III were considered. Candidates were evaluated according to our inclusion/exclusion criteria. Inclusion criteria comprised subjects between 18 years and 70 years old exhibiting localized excess of adipose tissue, skin laxity and/or skin imperfections in the area to be treated. Subjects under the age of 18, over the age of 70 and/or presenting any of the treatment contraindications (S1) were excluded. After a complete explanation of the protocol, written informed consent and photographic authorization were obtained from all the participants. Additionally, all subjects were asked to continue with their usual lifestyle throughout the duration of the treatments. The CONSORT flow diagram of the participants in the trial was included in the (S2).

2.2. Treatment Design

The treatment protocol consisted of 8 Symmed sessions targeting the abdomen/flanks area. Each session had a duration of 30 min and 72/96 h were left between them. Both capacitive and resistive RF energy modalities were employed during each session. The procedure involved the progressive application of RF energy until tissue hyperthermia was achieved, maintaining a surface temperature of 41°C for a duration of 10 min.

To evaluate the efficacy and safety of the treatment, measurements were taken at baseline (before the treatment) and at a 1‐ week follow‐up (S3).

2.3. Body Contour Measurements

Circumference evaluation was performed with a standardized measuring tape and in a standardized standing position. Body contours were taken at 3 different heights: upper contour (H1) was measured above the umbilicus, middle contour (H2) at the umbilicus height and lower contour (H3) under the umbilicus. Measuring sites for each subject, noted as height from the floor and distance from the dawn line axis (S4) were documented.

2.4. Photographic Assessment

Before and after treatment photographs were performed with a digital camera (CANON EOS 60D) in standardized position and lighting conditions. Subjects were positioned on a fixed floor template in front of a graduated panel with their arms bent. Photographs from the front, right side, left side, and back were taken. Before and after photos were combined using Photoshop software (24.1.1 version). Later, these images were used to perform a blind photographic evaluation of the treatment results. Three medical doctors of the aesthetic field (B. M., C. J., and M. P.) evaluated and identified the before and after (follow‐up) images of the abdomen/flanks area procedures, and the success rate was estimated.

2.5. Ultrasound Evaluation

Ultrasound analysis of subcutaneous adipose tissue thickness and dermal echogenicity (DE) was made using the DermaLab® Combo Cortex device (Cortex Technology) at baseline and follow‐up sessions. Ultrasound images and the associated quantitative data were obtained at 3 points (S4). Subcutaneous fat layer thickness was assessed using a 10 MHz frequency probe as the distance between the deep dermis and the deep fascia membrane. DE was evaluated with a 20 MHz focused ultrasound probe as an indirect indicator of dermal collagen content. Collagen is a highly eco‐rich and abundant protein of the dermal extracellular matrix that reflects ultrasound waves to a greater extent compared to surrounding structures. Therefore, by quantifying the echogenic changes (brightly colored areas), dermal collagen content increase can be indirectly assessed [12, 13].

2.6. Participant Satisfaction and Safety Assessment

The evaluation of satisfaction level was carried out 1 month after the final measurements according to a survey designed by Termosalud SL (S5). Questions regarding treatment process, satisfaction level and possible adverse effects occurrence were registered by selecting one pre‐established answer or according to a numerical scale (from 0 to 10).

2.7. Statistical Analysis

The results of the study were analyzed using the R software (4.3.0 version) and its Rcmdr package (2.8‐0 version) for Windows. Descriptive analysis, including means, medians, ranges, and standard deviations was calculated to express the improvement in DE, adipose tissue thickness and body circumferences, and the blind photographic evaluation success rate. The Kolmogorov–Smirnov test was used to assess if the variables were normally distributed. Non‐normality was assumed for all statistical tests performed with sample sizes smaller than 20 individuals. Comparisons before and after treatment were performed using Wilcoxon's signed‐rank test for matched pairs (non‐normality or n < 20). The statistical significance was set at p‐value < 0.05 (95% CI). Effect size was estimated for each significant statistical test with the R correlation coefficient (r). Results were considered as small effect size (0.1 ≥ r ≤ 0.3; slight differences between the two groups), moderate effect size (0.3 ≥ r ≤ 0.5; medium differences between the two groups) or large effect size (r ≥ 0.5; high differences between the two groups) [14].

3. Results

All 15 participants completed the 8 RF sessions of the study and their corresponding assessments. The age range of the volunteers included in the trial varied between 30 and 62 years old, with an average age of 44.20 ± 9.27 years old. A mean reduction in body weight of 0.55 ± 1.41 kg was noticed (Table 1).

Table 1.

Demographic information and outcomes of Symmed study.

Parameter | Measurement	Values		p‐Value
Age range (years)	30–62		—
Gender (n)	Female	14	—
	Male	1	—
Body weight loss (mean ± SD; kg)	0.55 ± 1.41		—
Abdomen/flanks contours reduction (median ± SD; cm)	H1	1.75 ± 1.10	0.002*
	H2	3 ± 2.16	0.003*
	H3	1.50 ± 0.94	0.0007*
Fat layer thickness reduction (median ± SD; %)	9 ± 11		0.00000008*
Skin echogenicity increase (median ± SD; %)	12 ± 25		0.012*

H1: upper contour; H2: middle contour; H3: lower contour. SD: standard deviation. n: sample size.

^* p‐value < 0.05.

3.1. Assessment of Abdomen/Flanks Measurements

Body circumference measurements were evaluated in standardized conditions at 3 different heights of the abdomen/flanks (Figure 1; Table 1). In the upper area (H1), a significant 1.75 ± 1.10 cm reduction (2%; range: 0.30–3.50 cm) was observed, on average (W = 78; p = 0.002; r = 0.88). In the intermediate region of the treated area (H2), a mean reduction of 3 ± 2.16 cm (3%; range: 0.50–8.50 cm) was noticed (W = 66; p = 0.003; r = 0.88). In the lower abdomen/flanks (H3), an average reduction of 1.50 ± 0.94 cm (1%; range: 0.50–3.50 cm) was observed (W = 120; p = 0.0007; r = 0.88).

Figure 1.

Evaluation of abdomen/flanks contours after Symmed treatment. Before and after treatment circumference measurements (cm) at the (A) H1, (B) H2, and (C) H3 heights. Normalized representations of the change at (D) H1, (E) H2, and (F) H3 points. Sample sizes of n = 12 (H1; A and D), n = 11 (H2; B and E), and n = 15 (H3; C and F). H1: upper contour; H2: middle contour; H3: lower contour.

3.2. Ultrasound Analysis of Subcutaneous Fat Layer Thickness

The subcutaneous fat layer thickness was measured as the distance (mm) between the deep dermis line and the deep fascia membrane (Figure 2; Table 1) at baseline and the follow‐up session. After 8 sessions, a significant mean reduction of 9 ± 11% in subcutaneous tissue thickness of the abdomen/flanks was observed (W = 741; p = 0.00000008; r = 1.39).

Figure 2.

Evaluation of subcutaneous adipose tissue thickness reduction in abdomen/flanks after 8 Symmed sessions (n = 38). (A) Normalized representation of the abdominal fat variation. (B) Ultrasound scans of a participant showing a fat tissue thickness reduction of 3.9 mm after the treatment. ▷ Deep dermis line; AT: adipose tissue (hypodermis); Deep fascia membrane. M: muscle.

3.3. Evaluation of DE and Collagen Content

Dermal echogenicity was assessed with an ultrasound probe (Figure 3; Table 1). The outcomes were used as an indirect measurement of the collagen present in the dermis. After treatment, DE was increased on average by 12 ± 25%, with maximum values of 74%. The gain represented a significant improvement in skin echogenicity (W = 19; p = 0.0125; r = −0.63).

Figure 3.

Ultrasound analysis of skin echogenicity in abdomen/flanks following Symmed treatment (n = 15). (A) Normalized representation of DE improvement in the abdominal area. (B) Skin ultrasound images of a participant showing a DE increase of 29.49% (yellow). Ep: epidermis; De: dermis.

3.4. Visual Effect Following Symmed Treatment

Visual analysis of treatment effectiveness was performed using photographs from different perspectives (Figure 4). The results of the blind photographic evaluation revealed an average success rate of 84.45 ± 3.85% (80.00–86.67%) when the evaluators identified the images taken before the beginning of the procedures. 86.67% of the photographs were correctly recognized by at least 2 of the 3 evaluators. Visually, after the treatment in the abdomen/flanks, a reduction in skin laxity was observed, thus improving the overall appearance of the skin. The body volume reduction in the treated area was also remarkable in a high percentage of the participants.

Figure 4.

Before and after treatment photographs of 4 participants exhibiting abdominal volume reduction.

3.5. Analysis of Satisfaction Level and Report of Adverse Events

Satisfaction questionnaires were completed by the participants 1 month after treatments. The surveys showed a high satisfaction, with 86.67% of the subjects (n = 13) expressing a compliance level from 7 to 10. 13.33% (n = 2) of the participants were moderately satisfied with their treatment results (satisfaction level 5–6), and none (n = 0) were not satisfied (satisfaction level 0–4). All the participants (n = 15) also affirmed they would recommend the same treatment to other people.

Symmed treatment was well tolerated with mild discomfort in 46.67% (n = 7) of the cases, resulting from moderate skin heating. Erythema, a minor adverse effect, was detected after 1 treatment session in 2 participants (13.3%) and resolved within 24 h. No severe events were reported.

4. Discussion

This study evaluated the beneficial effects of volumetric tissue heating using the Symmed device for noninvasive procedures. Symmed employs an electromagnetic current combined with thermal optimization technology to enhance the benefits of RF. After 8 treatment sessions, the 15 volunteers showed noticeable improvements in both the volume and skin condition of the abdomen/flank region. The versatility of Symmed technology allows for a wide range of treatments with a single device, adapting to each patient's needs by combining different working modes (capacitive and resistive) and a variety of available electrodes. This adaptability enables the device to target multiple tissue layers and induce multilayer biological effects [15, 16, 17, 18, 19].

In the resistive transmission mode, Symmed concentrates a significant portion of its energy in subcutaneous tissues, promoting the reduction of fat tissue and body contours [20, 21, 22]. In our study, we observed significant reductions of 9% in subcutaneous tissue thickness and 2.01 cm in body circumferences. These improvements align with previous clinical studies on the effectiveness of noninvasive RF devices. For instance, Anolik et al. evaluated the monopolar ThermaCool TC System (Solta Medical Inc.) for body contouring and reported an average waist circumference reduction of 1.4 cm [23]. Similarly, Manuskiatti et al. used a TriPollar RF device (Regen™, Pollogen Ltd.) in an 8‐session treatment, showing a nonsignificant reduction of 4% in abdominal fat layer thickness [24].

The action of RF in adipose tissue and adipocytes has been extensively investigated [1]. Regardless of the device's electrical configuration (monopolar, bipolar, tripolar or multipolar) it has been proposed that RF‐induced heat is conducted to deeper skin layers (hypodermis and muscle), where increased temperature induces metabolic changes in adipocytes [7, 19, 25]. Modifications in adipocyte volume and morphology have been detected, with cells exhibiting less fat content, decreased volume (adipocyte hypotrophy), and polyhedral or irregular shapes instead of rounded morphologies [7, 9, 25]. Additionally, some studies have reported total or partial lysis of adipocyte membranes after RF treatment, suggesting that these modifications are related to enhanced lipolysis and lipid turnover [7, 26, 27]. Moreover, other studies have demonstrated that RF treatments led to an extrusion of intracellular lipid content, resulting in increased levels of free fatty acids and glycerol in blood plasma and changes in adipocyte histology [19, 26, 28]. This further supports the activation of fat metabolism and the consequent reduction of fat tissue and contouring effect.

In contrast, Symmed's capacitive working mode focuses a significant portion of its energy and thermal effect on the epidermal and dermal layers of the skin. The dermis is primarily composed of collagen (mainly types I and III), synthesized by fibroblasts and responsible for its tensile properties [17]. Our clinical outcomes showed a significant increase of 12% in dermal echogenicity and, subsequently, dermal collagen after Symmed treatments. Several trials have proven RF's efficacy in stimulating collagen synthesis by increasing fibroblast activity and remodeling collagen fibril architecture in the dermal matrix [4]. For example, Zelickson et al. used the monopolar and capacitive RF device ThermaCool TC for abdominal treatments and observed increased dermal collagen type I mRNA expression compared to nontreated skin [29]. Monaretti et al. also noted a nonsignificant increase in skin collagen content (1.03%) using a capacitive and monopolar RF device (BTL‐6000 TR‐Therapy Pro) for abdominal skin tightening [30]. RF's impact on collagen content extends to facial treatments as well, with El‐Domyati et al. reporting significant increases in newly synthesized collagen (6.4%), dermal collagen type I (6.4%), and type III (5.6%) when using a monopolar and capacitive RF device (Biorad, Shenzhen GSD Tech Co) [17]. Taken together, our results and those of previous research with equivalent technologies, support the effectiveness of Symmed capacitive treatment for the improvement of skin quality.

According to the previous investigations, the effect of capacitive RF on fibroblasts and collagen metabolism would play a central position improving skin appearance [4]. To date, several mechanisms triggered by controlled heating have been described. On the one hand, researchers have found an increase in the expression of molecules involved directly or indirectly in collagen synthesis as a response of fibroblasts to hyperthermia. These molecules are crucial in the processes of fibroblastic proliferation (cyclooxygenase 2, COX‐2 and fibroblast growth factor 2, FGF2), and, therefore, in the production and incorporation of new collagen into the dermal matrix (heat shock protein 47, HSP‐47) [20, 31]. On the other hand, the RF‐related stimulation also appears to affect the three‐dimensional structure of collagen. When heated, collagen undergoes a transition from a highly organized structure to a contracted state through denaturation. This contraction induces dermal matrix remodeling and tissue retraction. Finally, the combination of new collagen content and dermal matrix reorganization enhances the visual appearance of the skin [17, 20].

The previously described effects provide evidence of the safety and efficacy of the Symmed RF‐based device. Heating the epidermal, dermal, and hypodermal tissues to hyperthermia improves skin laxity and reduces body contours and adipose tissue thickness. Future studies should include detailed histological analyses to quantify the amount of adipose tissue elimination, collagen synthesis, and reorganization. However, the current findings demonstrate a remarkable improvement following Symmed treatment protocol.

5. Conclusion

Symmed RF‐based treatment is an effective, safe, and well‐tolerated procedure. The results demonstrate the effectiveness of the treatment reducing skin laxity, improving the appearance of the skin, and decreasing the thickness of adipose tissue in the abdomen/flanks to body contouring and skin firming effect.

Author Contributions

All authors contributed to the study performance and approved the final content of the article. A.I.F. and L.S.F. were involved in participants recruitment, scheduling, and performance of treatments and safety supervising. S.V.F.L.H.Z., and A.F.S. were involved in recruitment, study design, study supervising, data acquisition, analysis and interpretation, and manuscript drafting.

Ethics Statement

The trial was approved on September 22, 2022 by the Research Ethics Committee of the Principality of Asturias (Spain) under the registration number 022.340. It was conducted according to the criteria established by the Declaration of Helsinki (1964) and its later amendments. Written informed consent and photography consent was obtained from all the volunteers included in the study.

Conflicts of Interest

The research team of this study was composed of Termosalud SL (Gijón, Spain) company employees. The research was supervised by the Asturias Ethics Committee and an authorized Clinical Research Associate (CRA) to ensure the right performance of the study and the correct validation of the obtained results. The authors of the paper are responsible for the content of the article.

Supporting information

Supplementary Material_Revision 1.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.