Split-face Study Research Articles

Superficial Intradermal Injections of Cohesive Polydensified Matrix Hyaluronic Acid Fillers for the Improvement of Facial Pores and Skin Quality: A Split-Face Randomized Study.

Various therapeutic options have been introduced for enlarged facial pores including low cross-linked hyaluronic acid (HA) fillers. Newer formulations of HA-based dermal fillers are continuously introduced into the market, but their effectiveness in reducing enlarged facial pores has not yet been determined. To compare the efficacy of HA-based dermal fillers (Cohesive Polydensified Matrix HA filler; CPM-HA20) versus CPM-HA20 with glycerol (CPM-HA20G) in terms of minimizing enlarged facial pores and skin quality improvement. Thirty subjects with enlarged facial pores were enrolled in this randomized, double-blinded, split-face study. Participants were randomly assigned to be injected with 1 mL of CPM-HA20 filler on one side of their medial cheek and 1 mL of CPM-HA20G on the contralateral side for 3 sessions spaced 4 weeks apart. Pore volume was objectively measured by an Antera 3D. Skin biophysical properties were evaluated. Participant satisfaction and adverse events were recorded. Twenty-nine participants completed the study. Both treatment groups showed a reduction in the mean pore volume from the baseline through Week 32. The CPM-HA20G treated side showed a 24.2% higher reduction in mean pore volume from baseline compared to the CPM-HA20 treated side (p = 0.038). Both treatment groups showed improvement in skin hydration from baseline to Week 32. There was no significant difference in patient satisfaction between the CPM-HA20G and CPM-HA20 treated sides. Only mild adverse events such as pain, edema, and bruising were reported. Three-monthly injections of CPM-HA20G and CPM-HA20 were effective in minimizing enlarged face pores and improving skin hydration. CPM-HA20G demonstrated superior efficacy in terms of pore size reduction. Adverse events were generally mild and tolerable.

Improvement in Skin Moisturization and Lack of Barrier Damage Following Treatment With Clascoterone Cream 1.

Topical medications commonly prescribed for the treatment of acne vulgaris may be limited by application-site dryness, which can result in skin barrier damage. This study aimed to evaluate the effects of clascoterone cream 1% on skin barrier properties in acne-prone individuals. Participants ≥18 years of age with acne-prone skin were enrolled in a single-center, split-face study and randomized to twice-daily treatment with clascoterone cream 1% (approximately 0.5 g) to the right or left side of the face for 2 weeks. The primary and secondary endpoints were the changes in corneometry reading and transepidermal water loss (TEWL), respectively, between treated and untreated sides at week 2. Tolerability was evaluated from the severity of dryness, erythema, scaling, irritation, tightness, stinging, itching, and burning for each side using a 5-point scale from 0 (none) to 4 (severe). This study enrolled 50 participants (female, n = 38) with a mean ± standard deviation (SD) age of 31.1 ± 8.9 years. The mean ± SD corneometry reading was significantly higher for the treated vs untreated side at week 2 (131.3 ± 42.9 vs 113.9 ± 36.6; P<0.001). There was no difference in TEWL between treated and untreated sides at any time point assessed. All tolerability parameters evaluated were rated as absent or minimal through week 2 for both sides. Twice-daily treatment with clascoterone cream 1% for 2 weeks was associated with increased moisturization and maintenance of skin barrier function as assessed by corneometry and TEWL and was otherwise well tolerated. J Drugs Dermatol. 2025;24(4):397-402. doi:10.36849/JDD.8774.

The potential role of tranexamic acid and botulinum toxin in treating patients with acne vulgaris: a split face comparative study.

Many causes can lead to acne, such as increased sebum production, altered sebum lipid quality from increased androgen activity, abnormal keratinization of the infundibular epithelium, and Propionibacterium acnes (P. acnes) colonizing the follicles. The present study aimed to evaluate and compare the clinical efficacy of botulinum toxin-A vs. tranexamic acid intradermal injection in the treatment of acne vulgaris. This split face study includes forty patients with varying grades of acne vulgaris. They were injected intradermally with tranexamic acid (20mg/ml) on the left side for three sessions two weeks apart and once with botulinum toxin-A on the right side. After treatment, the Total Lesion Count, Comprehensive Acne severity Scale, and Clinical Erythema Assessment Scale significantly reduced, with a greater reduction in erythema on the tranexamic acid side and a greater reduction of comedones on the botulinum toxin side. Tranexamic acid and botulinum toxin-A can be promising adjuvants in treating acne vulgaris by their specific mechanisms in the dermatological domain.

Fractional CO2 laser with topical insulin versus PRP for atrophic acne scars: a randomized split-face study.

Atrophic acne scarring is a prevalent problem that has been treated with a variety of procedures, each with various degrees of success. For better results, combined regimens of treatment are recommended. Our aim was to compare the efficacy of topical insulin against topical platelet-rich plasma (PRP) as an adjunct treatment to fractional CO2 laser for atrophic acne scars. The study comprised 30 patients with atrophic acne scars. All patients underwent four sessions of fractional CO2 laser on both sides of the face at one-month intervals, followed by topical PRP treatment on one side of the face and topical insulin on the other. Two non-treating dermatologists used the Acne Scar Assessment Scale (ASAS) to assess the outcome. At their last follow-up appointment, patients were asked to assess their improvement on each side of the face in a percentage from 0 to 100%. Prior to treatment, there was no difference in the ASAS scores between the two sides of the face. One month after the last treatment session, ASAS scores improved significantly on both sides of the face. No significant difference (p = 0.794) between both sides were detected. Both techniques helped to improve atrophic acne scars and may have a synergistic outcome regarding efficacy and safety.

Effect of Subcutaneous Injection of Tranexamic Acid on Ecchymosis and Edema after Oculofacial Surgery: A Prospective, Randomized, Split-Face, Double-Blind Study

Abstract Background Tranexamic acid (TXA) is an antifibrinolytic that is regularly used to reduce bleeding in surgical specialties. Objectives To assess the effects of subcutaneous TXA in oculofacial plastic surgeries, with the hypothesis that TXA reduces postoperative ecchymosis and edema. Methods A prospective, randomized, double-blind, split-face study. The sides of the face were randomized to local anesthetic (bupivacaine with epinephrine) mixed with TXA or sodium chloride (placebo). Photographs were taken immediately post-operatively and on post-operative day 7. Photographs were graded by two masked investigators using the Surgeon Periorbital Rating of Edema and Ecchymosis criteria. Patients selected the side that they subjectively determined to have less ecchymosis and edema. As a secondary outcome, patients rated pain on each side of their face using the Wong-Baker FACES pain scale. Results Twenty-four patients undergoing bilateral, symmetric oculofacial surgery were included in the study. There was a statistically significant difference in postoperative periocular ecchymosis on POD7 (with TXA 0.91 ± 0.73 versus placebo 1.61 ± 1.03; p = 0.020) and in periocular edema on POD1 (with TXA 1.30 ± 0.76 versus placebo 2.00 ± 0.85; p = 0.028). All patients selected the side of the face receiving TXA as having less periocular ecchymosis and edema. There was no statistically significant difference in subjective pain level between the side receiving TXA versus placebo. There were no intraoperative or postoperative complications. Conclusions Subcutaneous TXA was safe and reduced periocular ecchymosis and edema compared to contralateral placebo injections in this series of patients undergoing bilateral oculofacial plastic surgeries.

Comparison of efficacy and safety of low-fluence neodymium-doped yttrium aluminium garnet laser versus glycolic acid peeling in patients of melasma: A split-face study

Comparison of efficacy and safety of low-fluence neodymium-doped yttrium aluminium garnet laser versus glycolic acid peeling in patients of melasma: A split-face study

Comparison of the Effects of Adipose Extracellular Matrix/Stromal Vascular Fraction Gel Injection and CO2 Fractional Laser on Atrophic Acne Scar in Asians Through a 24-Week Prospective, Randomized, Split-Face Study.

Adipose extracellular matrix/stromal vascular fraction gel (ECM/SVF-gel) contains adipose-derived stem cells, extracellular matrix, and other cell components, and possesses the ability to promote collagen production and serve as a filling agent. To assess the efficacy and safety of ECM/SVF-gel injection for the treatment of acne scars, compared to CO2 fractional laser (CO2FL). We performed an open-label, investigator-initiated, assessor-blinded, split-face trial in Xijing Hospital, China, between July 11, 2020, and December 30, 2022. Patients exhibiting moderate to severe acne scars were randomly assigned to a single ECM/SVF-gel injection on one half of the face or two sessions of CO2FL treatments on the other half. The primary outcome was the change in total Echelle d'Evaluation Clinique des Cicatrices d'acne (ECCA) score from baseline to 24-week follow-up. Secondary outcomes included the changes in the volume of scars assessed by the Antera 3D software. A total of 11 participants were enrolled, and 10 completed the follow-up. The mean age of patients was 27.5 ± 4.2, 7 female and four male, seven with Fitzpatrick skin Type III and four with Type IV. At 24weeks, the mean change in ECCA score was -60.25 on the side of ECM/SVF-gel injection and - 43.25 on the side of CO2FL treatment (difference:-17.00 [95% CI: -24.56 to -9.44], p < 0.001). Antera 3D photography analysis showed that the mean change in scar volume was -33.17% on ECM/SVF-gel injection and -19.69% on CO2FL (difference: -13.48% [95% CI:-22.16% to -4.79%], p = 0.004). ECM/SVF-gel injection is an effective and safe approach in the treatment of acne scars. ClinicalTrials.gov number: NCT06116162.

Efficacy of Topical Oxytocin With Micro-Needling in the Treatment of Facial Skin Ageing: A Randomised, Placebo-Controlled, Split-Face Study.

Efficacy of Topical Oxytocin With Micro-Needling in the Treatment of Facial Skin Ageing: A Randomised, Placebo-Controlled, Split-Face Study.

Comparison of multiple 1565 nm fractional Er: glass laser and single fractional CO2 laser in the treatment of atrophic acne scars: a prospective, randomized split-face study

ABSTRACT Both ablative fractional laser (AFL) and non-ablative fractional laser (NAFL) are gaining popularity in the treatment of atrophic acne scars. However, single NAFL may not be as effective as single AFL in clinical practice. This split-face and evaluator-blind study compared the efficacy and safety of multiple consecutive NAFL (1565 nm Er: glass laser) and a single AFL (10600 nm CO2 laser) in the treatment of facial atrophic acne scars. 13 subjects with V, U and M-shape atrophic scars were treated with either NAFL group (once a month for 3 consecutive sessions of 1565 nm Er: glass laser) or AFL group (a single session of fractional CO2 laser). We found that both AFL group and NAFL group showed decreased 4-point scale and ECCA scores for respective V, U, M types, but there was no statistically difference between the two groups. NAFL group showed lower pain score, less oozing and crusting, and shorter duration of the adverse effects as well. The average satisfaction score was higher in NAFL group, although there was no statistically significance. In conclusion, consecutive triple NAFL treatment could approach a single AFL treatment for atrophic acne scars, while NAFL treatment causes less pain and fewer adverse events.

Evaluation of Efficacy and Safety of Fractional CO2 Laser Versus Micro-Needling with Autologous Platelet-Rich Plasma in Treatment of Acne Scars – A Split Face Study

Evaluation of Efficacy and Safety of Fractional CO₂ Laser Versus Micro-Needling with Autologous Platelet-Rich Plasma in Treatment of Acne Scars – A Split Face Study

Comparative Efficacy and Tolerability of Imiquimod 3.75% Cream vs 5-Fluorouracil 4% cream in the Treatment of Actinic Keratosis: A Split-Face Study.

Actinic keratosis (AK) is a common precancerous skin lesion that arises on chronically UV-exposed skin and that can progress to keratinocyte carcinoma. The aim of this study was to compare the efficacy, safety, local skin reaction, time to wound healing, and patient preference of imiquimod (IMQ) 3.75% vs 5-fluorouracil (5-FU) 4% cream treatment for AKs. Two symmetrical contralateral areas of approximately 25 cm2 harboring a similar (≥5) number of AKs were selected and randomly assigned to IMQ 3.75% or 5-FU 4% cream treatment. The total number of AKs for each patient was evaluated at baseline (T0) and 90 days after the end of treatments (T1). Local skin reaction (LSR) score was registered the day after the end of both treatments. Complete remission rate of lesions, cosmetic outcome, and patient preference of treatment were assessed after 90 days (T1). The mean variation (ΔT0-T1) of AKs was not significantly different in patients treated with IMQ 3.75% vs 5-FU 4% (P = 0.35). The mean LSR was not significantly different between patients treated with IMQ 3.75% and those with 5-FU 4% (p=0.63). No difference in cosmetic outcome was observed in the two groups. Patient preference was equally distributed between the treatments. The mean time to wound healing after the end of the treatment was similar with IMQ 3.75% and with 5-FU 4% (P = 0.83). This study reports a non-superiority of efficacy, tolerability, wound-healing time, and cosmetic outcome of topical IMQ 3.75% treatment compared to topical 5-FU 4% treatment in AK management.

Topical silymarin versus combined topical silymarin and microneedling in treatment of melasma: split-face study

Background Melasma is a common acquired pigmentary skin disease that is more predominant in females and darker skin types. Objectives To evaluate and to compare the efficacy and safety of topical silymarin alone and of combined topical silymarin and microneedling in the treatment of melasma. Patients and methods The study design was a split-face, right-left, randomized controlled trial, which was done on 30 adult patients with melasma. History taking and dermatological examination were done. Each side of the patient’s face was randomly (by closed envelop method) allocated to either topical silymarin 0.7% and microneedling or topical silymarin 0.7% alone. All patients were assessed monthly by hemi-Melasma Area and Severity Index (MASI) score hemi-modified Melasma Area and Severity Index (mMASI) score by comparing hemi-mMASI score throughout the 3-month treatment course, patient self-assessment scale, and Melasma Quality of Life Scale. Results There was an insignificant difference in the mean hemi-MASI and hemi-mMASI scores between both sides at each study point (P&gt;0.05 for each). Mean hemi-MASI and hemi-mMASI scores showed significant (P&lt;0.001 for each) steady reduction after treatment for both groups. Conclusions Both modalities of treatment can be used effectively and safely in the treatment of melasma.

Split-Face Comparison of Two Hyaluronic Acid Fillers: Intersection of Rheology and Tissue Behavior in Midface Rejuvenation.

Hyaluronic acid (HA) fillers are one of the most popular aesthetic treatments for midface volumization, achieving optimal aesthetic improvements. Given the variety of HA filler products available, it is important for injectors to understand how their rheological properties can influence behavior in tissues. To evaluate and compare (1) product integration and dynamic support and (2) lifting capacity of 2 rheologically different HA fillers (HA Contour [HACON] and HA Voluma [HAJVOL]) through ultrasound and clinical photography. Randomized, split-face study (n = 11) comparing 2 midface HA fillers over a 12-month period with initial injection along the zygomatic arch at Day 0 and optional touch-up at Month 1. Eligible patients were aged 22 to 65 years with midface volume loss and contour deficiency. Assessments included ultrasound (neutral and smiling), clinical photography with 3D volume change (lifting capacity) analyses, and adverse event reporting. Volume change was assessed at 2 regions: midface and infraorbital hollow (IOH). With similar average total injection volumes, both fillers had comparable lifting capacity in the midface (HACON: ≥2.07 mL and HAJVOL: ≥2.08 mL; P > .05) and IOH (HACON: ≥0.45 mL and HAJVOL: ≥0.57 mL; P > .05) areas for up to 12 months. Ultrasound showed that HACON integrated into the tissue, stretching and elongating during a smiling expression, whereas HAJVOL did not integrate as much, with aggregates consistent in size and shape during both neutral and smiling expressions through 12 months. No adverse events were reported during the study. HACON demonstrated a similar duration of lifting capacity (volumization) as HAJVOL but had more distributed product integration and flexibility to support dynamic expressions through 12 months.

Effects of Botulinum Toxin Type A Treatment on Clinical and Biophysical Parameters in Patients With Erythematotelangiectatic Rosacea: A Prospective, Randomized, Controlled, Double-Blind Study.

Erythematotelangiectatic rosacea (ETR) lacks a gold-standard treatment. Recent studies show that intradermal Botulinum Toxin-A (BoNT-A) is effective for erythema, though objective data are limited. This study aims to evaluate the efficacy and tolerability of intradermal BoNT-A in patients with ETR. In this randomized, double-blind, split-face study, 30 patients were enrolled. One side of the face received 15 units of BoNT-A, reconstituted in 10 mL of saline, while the control side received saline injections. Assessments were made at baseline and 1-month posttreatment. Clinician's Erythema Assessment (CEA) scale and Patient Self-Assessment (PSA) scores were recorded. Erythema and Melanin Index measurements using a Mexameter. Background erythema was assessed through dermatoscopy, while vascular structure and density were evaluated using Investigative Global Assessment (IGA) scores through videocapillaroscopy. The BoNT-A-treated side demonstrated significant reductions in CEA scores, Erythema Index, and dermatoscopic background erythema, while no significant changes were observed on the saline control side. IGA scores indicated a significant response to treatment on the BoNT-A side. Patient Self-Assessment scores improved on both sides. No serious adverse events requiring hospitalization were reported. Intradermal BoNT-A effectively reduces erythema and vascular density in patients with ETR and is well-tolerated.

Combined micro-needling with topical metformin versus micro-needling with topical placebo in the treatment of melasma: a concurrent split-face study.

Melasma is an acquired dysfunction of melanogenesis, that poses a major therapeutic challenge and tends to recur after therapy. Several combination therapies are being tested nowadays for the treatment of melasma, with promising results. Metformin, an anti-diabetic medication, seems to inhibit melanogenesis by different mechanisms. In addition, there has been a long-term improvement in melasma after microneedle therapy. To evaluate the potential therapeutic role of topical metformin combined with micro-needling for the treatment of melasma. Eighteen patients with melasma received treatment in split-face manner, right side with micro-needling and topical metformin, while the left side was treated with micro-needling and topical placebo for four sessions at 2-week intervals. Hemi-mMASI score was used for the final evaluation of results. ThevariabilitypatterninHemi-mMASI score between both sides revealed significant reduction in the right side (micro-needling + metformin), as compared to the left side (micro-needling + placebo) (2.39 ± 1.42 vs 4.72 ± 1.27, p = 0.001). The effectiveness of topical metformin in the management of melasma could be significantly improved by pretreatment with micro-needling as a combined therapy, without any apparent side effects.

Resolving the Controversy Surrounding the Function of the Corrugator Supercilii Muscle.

The corrugator supercilii muscle (CSM) has traditionally been recognized as a primary depressor of the eyebrows, playing a key role in expressing negative emotions and contributing to the formation of glabellar lines. However, recent studies indicate that the CSM may exhibit movements contrary to those previously documented, suggesting a more complex functional role. This research re-evaluates the anatomical and functional roles of the CSM and discusses their implications for botulinum toxin treatments. A prospective, intrapersonal comparative, and split-face study was conducted over a five-year period, from January 6, 2019, to January 6, 2024, involving 298 patients who underwent botulinum toxin injections. The study divided participants into seven groups, each targeting specific anatomical areas of the CSM and associated muscles. Injection techniques were varied to assess their impact on brow dynamics, with outcomes measured by changes in eyebrow position and expression lines. The study demonstrated that targeting specific portions of the CSM and depressor supercilii muscle (DSM) leads to distinct outcomes in brow elevation and the reduction of expression lines. However, this approach was also frequently associated with the development of omega-shaped wrinkles. Split-face evaluations further validated that the modified injection techniques achieved superior eyebrow elevation compared to traditional methods. This study challenges the traditional view of the CSM as primarily a brow depressor, highlighting its role in medial brow elevation. These findings underscore the need for a nuanced approach in esthetic medicine, particularly in botulinum toxin injections, to achieve balanced and natural facial expressions. Understanding the full range of CSM functions is crucial for optimizing esthetic outcomes and enhancing patient satisfaction. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Mask wearing impacts skin barrier function and microbiome profile in sensitive skin

Mask-wearing behavior, common in the post-COVID-19 era, raises concerns for sensitive skin. This split-face study investigated mask-related changes in skin barrier function and microbiome composition among 30 female volunteers with sensitive skin and assessed the mitigating effects of a moisturizer containing biological lipids and probiotics. Skin physiological indicators (transepidermal water loss, erythema index, stratum corneum hydration, pH, temperature) of masked and unmasked areas were collected at baseline, after three hours of mask-wearing, post-tape stripping, and after 24 h, respectively. Microbiome samples collected from the masked areas before and after wearing a medical mask were analyzed with bioinformatics methods. Mask-wearing significantly weakened barrier function in both masked and adjacent unmasked areas, while reducing bacterial diversity. It was also associated with an increase in Cutibacterium (P = 0.110) and decreases in Streptococcus (P = 0.032) and Prevotella (P = 0.026) abundance. Moisturizer application prior to mask-wearing significantly reduced transepidermal water loss and erythema (both P < 0.001) and further improved erythema after 24 h (P = 0.048). These findings demonstrate that mask-wearing can disrupt the skin barrier and microbiome in individuals with sensitive skin and applying a moisturizer beforehand can mitigate mask-related discomforts by aiding barrier repair and reducing sensitivity.

Application Characteristics and Patient Preference of Triple-Combination vs Layered Topicals for Acne: Split-Face Study.

Although triple-combination therapies for acne are generally more efficacious than dual-combinations or topical monotherapy, this benefit may be offset by reduced adherence to a complicated treatment regimen. Clindamycin phosphate 1.2%/adapalene 0.15%/benzoyl peroxide 3.1% (CAB; Cabtreo&reg;, Ortho Dermatologics) gel is the first triple-combination topical approved for the treatment of acne. By delivering multiple active ingredients as a fixed-dose combination, CAB gel may improve ease of use, which can benefit both treatment adherence and efficacy. The objective of this study was to compare the application characteristics of CAB gel with the layered application of its 3 individual active ingredients. In this split-face study, adults with acne-prone skin (N=25), self-applied CAB gel (0.3 cc) to 1 side of the face and layered benzoyl peroxide cream, adapalene gel, and clindamycin gel (0.1 cc each) on the opposite side. CAB and clindamycin gels were compounded with pyranine, which fluoresces under blue light. Photos taken under blue light were used to assess the uniformity of product application, and participants rated the evenness, speed, and ease of the 2 application regimens, as well as overall preference. Investigator-assessed evenness of application favored CAB gel over layered application in 100% of participants. All participants rated the application of CAB gel as more uniform, easier, and faster. Most (96%) preferred CAB gel for use at home. Fixed-dose CAB gel was applied more evenly than separate application of its 3 active ingredients. By addressing 3 of the main acne pathogenic pathways in a single, easy-to-apply formulation, CAB gel may improve the efficacy of and adherence to acne treatment. J Drugs Dermatol. 2024;23(10):857-861. doi:10.36849/JDD.8430.

Nano-vesicular systems for melanocytes targeting and melasma treatment: In-vitro characterization, ex-vivo skin retention, and preliminary clinical appraisal

Nano-vesicular systems for melanocytes targeting and melasma treatment: In-vitro characterization, ex-vivo skin retention, and preliminary clinical appraisal

51410 A Novel Combination of Niacinamide, Hexyl Resorcinol and Retinyl Propionate Provides Superior Anti-Aging Benefits in an 8-week Split-Face Study

51410 A Novel Combination of Niacinamide, Hexyl Resorcinol and Retinyl Propionate Provides Superior Anti-Aging Benefits in an 8-week Split-Face Study