Teoxane announces new study reinforcing the biocompatibility, safety and efficacy of RHA®4 in dynamic facial support

Teoxane reinforces its commitment to scientific innovation with the publication of a new study in Plastic and Reconstructive Surgery – Global Open, providing robust preclinical and clinical evidence on the safety, biocompatibility, and performance of RHA®4* in midface augmentation.

The study confirms that RHA®4[1], a resilient hyaluronic acid filler designed for dynamic facial areas[2]^,[3], integrates harmoniously within subcutaneous adipose tissue, preserving its natural biomechanics while delivering effective volume restoration. Findings highlight its ability to promote rapid collagen formation and to support extracellular matrix remodeling, contributing to long-term structural and functional benefits. Clinically, RHA®4 was shown to safely and effectively lift both deep and superficial fat compartments without compromising facial expressiveness.

Additionally, the study reinforces the efficacy of Teoxane’s Multilayering Technique (MLT) as an efficient treatment approach, optimizing aesthetic outcomes and natural looking midface rejuvenation.

Study Methodology

The collaborative work involved a comprehensive preclinical research and clinical real-world evidence, including two case studies, one of those followed up for 2 years, to demonstrate the long-term safety and effectiveness of RHA®4 for midface augmentation, using the Multilayering Technique (MLT).  

Researchers assessed volume retention, longevity, safety, and the ability to sustain facial dynamics and expressions.

• Preclinical Biocompatibility Assessment:

To assess the performance of RHA®4 in subcutaneous layer, implantation study was performed over a 52-week period, focusing on long-term tolerability and tissue integration.

Ex vivo studies further explored the biomechanical impact of RHA®4 on soft tissue dynamics. In this model, 1 mL of RHA®4 was injected into human adipose tissue obtained from abdominoplasty procedures to assess its ability to project, support, and stabilize subcutaneous fat pads while preserving their natural movement.
 

• Clinical Performance:

A clinical data collection of 35 patients assessed the efficacy and safety of RHA®4 in midface augmentation.

Patients were treated at the Teoxane Academy by expert injectors, involving the Multilayering Technique, and guided by Teoxane’s ATP assessment protocol (Anatomy, Technique, and Product), to target both deep and superficial fat compartments.
The aesthetic outcomes are described in a selected case by means of Quantificare analysis, to show the anterior projection and lifting effect with minimal volume injection.

• Two-Years Case Study:
  
  To examine long-term performance, a 64-year-old patient with midface volume loss and sagging was treated by Dr. Fang-Wen Tseng using RHA®4 for deep volumization.

Key Findings

The study reinforced the safety, efficacy, and tissue integration properties of RHA®4, confirming its suitability for midface augmentation with long-term stability (up to 2 years) and natural aesthetic outcomes.

High Biocompatibility & Seamless Tissue Integration

• RHA®4 showed minimal tissue reaction, progressive gel absorption, and no fibroplasia, ensuring rapid collagen formation with minimal inflammation. Results demonstrated that RHA®4 preserved Tissue Dynamics. It increases overall tissue height, without altering the natural biomechanics of adipose tissue, indicating a high degree of mechanical compatibility and seamless integration into the fat layers.
   
• Validated Clinical Performance in Midface Augmentation: Findings validated RHA®4 suitability for midface augmentation, through its ability to lift both deep and superficial fat compartments, supporting the Multilayering Technique for patient-tailored stable volume restoration.
   
• Evaluations further demonstrated effective integration into the surrounding tissues, ensuring a natural aesthetic outcome while preserving dynamic facial expressions.

Long-Lasting Natural Results with No Migration

• Over two years of follow-up, the patient exhibited sustained volume restoration without touch-ups, with no signs of filler migration, underscoring RHA®4’s durability and optimal tissue integration.
• Its unique balance of strength and stretch ensures resilience against muscle movement contributing to stable, long-lasting rejuvenation over time both in static and dynamic conditions, while maintaining facial expressiveness and naturalness.

Enhanced Skin Quality Through Collagen Production

Beyond its volumizing properties, the preclinical research highlighted RHA®4’s role in stimulating collagen production, contributing to improved extracellular matrix remodeling and long-term clinical outcomes.

Proven Safety & High Patient Tolerability

RHA®4 showed a good safety profile, with minimal adverse events and no reports of severe complications. The findings reinforce RHA®4 as a well-tolerated and effective option for midface augmentation, with low incidence of swelling or prolonged reactions.

“This study represents a significant contribution to the aesthetics industry, reinforcing Teoxane’s commitment to advancing hyaluronic acid innovation. The findings demonstrate RHA®4's ability to provide natural-looking volume restoration by preserving the biomechanics of subcutaneous tissue during motion, thereby supporting the MLT approach. Additionally, the collagen deposition and subsequent progressive tissue integration highlight its role in enhancing skin attributes.” Jimmy Faivre - Teoxane Head of Research.

*RHA® 4 = Teosyal RHA® 4

Medical devices for professional use only. Product indications and availability vary from country to country. Please consult product instructions locally approved for more information.

Medical devices are regulated health products bearing the CE mark, CE2797, under the Medical Device Regulation (EU) 2017/745.

Contact for materiovigilance notification: medical@teoxane.com.

[1] Flégeau, Killian PhD; Ballarini, Stefania PhD; Brusini, Romain PhD; Vantou, Camille MEng; Liao, Zhifeng MD; Hirt-Burri, Nathalie PhD; Bourdon, François MEng; Tseng, Fang-Wen MD; Faivre, Jimmy PhD. Safety and Performance of RHA4 in the Midface Using the Multilayering Technique: Preclinical and Clinical Evidence. Plastic & Reconstructive Surgery-Global Open 13(2):p e6560, February 2025

[2] Teosyal RHA® 4 – Instructions for Use

[3] Faivre J, Gallet M, Tremblais E, Trévidic P, Bourdon F. Advanced Concepts in Rheology for the Evaluation of Hyaluronic Acid-Based Soft Tissue Fillers. Dermatol Surg. 2021 May 1;47(5):e159-e167