Background: Patient care following botulinum toxin injections has long been guided by anecdotal instructions, often based on theoretical considerations. This study evaluates the necessity of extended post-treatment instructions by analyzing outcomes and satisfaction in patients who followed only a 10 min precaution protocol. Materials and Methods: A retrospective, multicentric study was conducted across six Italian centers, analyzing 5014 patients treated with botulinum toxin for upper facial wrinkles between 2015 and 2020. Outcomes included adverse effects—particularly upper eyelid ptosis—and patient satisfaction. Follow-up was performed at two weeks. Results: No cases of upper eyelid ptosis were observed. Among 4000 patients who attended follow-up, adverse effects occurred in only 5.99%, notably lower than rates reported in the literature. Of the 2010 patients who completed the satisfaction questionnaire, 90% reported being very satisfied. These findings support the safety of limiting post-treatment instructions to 10 min. Conclusions: Our findings indicate that omitting extended post-injection instructions does not negatively impact patient satisfaction or complication rates. Given the toxin’s rapid internalization and localized effect, extended behavioral restrictions may be redundant. However, the absence of a control group and lack of statistical analyses limit the strength of these conclusions. In addition, this is a short-term study. Future prospective, randomized trials are needed to develop evidence-based post-care protocols to optimize esthetic outcomes, patient safety, and long-term efficacy.

Background: Hyaluronic acid (HA) hydrogels are the most widely used injectable fillers for facial rejuvenation. A new generation of HA fillers crosslinked with poly(ethylene glycol) diglycidyl ether (PEGDE) has been developed to enhance cohesiveness, tissue integration, stability, and longevity while minimizing swelling and immunogenicity. Owing to their distinct viscoelastic properties, PEGDE-crosslinked HA fillers may require product-specific selection and adapted injection techniques. Objective: The objective of this study is to provide practical, expert-based recommendations for the safe and effective use of PEGDE-crosslinked HA hydrogels in facial aesthetic treatments. Methods: A multidisciplinary panel of nine Italian experts in aesthetic medicine, each with more than 15 years of experience using HA fillers, developed consensus recommendations based on clinical practice and available evidence. A pre-meeting questionnaire informed structured discussions during a face-to-face meeting held in Paris in January 2024. The nominal group technique was applied, with consensus defined as agreement by at least 80% of panel members. Results: Consensus was reached on product selection, injection planes, delivery devices, techniques, and typical treatment volumes for PEGDE-HA hydrogels across multiple facial regions, including the forehead, temples, midface, nasolabial folds, chin, jawline, and lips. Recommended injection techniques included microbolus, macrobolus, and retrograde linear threading, with placement ranging from superficial subcutaneous to supraperiosteal planes depending on the anatomical area and clinical indication. Typical injection volumes generally ranged from 0.1 to 0.5 mL per side. Optional ultrasound mapping was considered beneficial in selected high-risk or superficial procedures to improve anatomical safety. Conclusions: These expert consensus recommendations provide practical guidance for clinicians using PEGDE-crosslinked HA hydrogels in facial rejuvenation. Tailoring product characteristics to injection depth, technique, and regional anatomy may help optimize clinical outcomes and procedural safety. Future research priorities include prospective comparative studies with other crosslinking technologies, standardized reporting of adverse events, long-term outcome registries, and further evaluation of ultrasound-guided injection strategies.

This proof-of-concept article introduces the “Dual Core Concept”, a novel facial rejuvenation model integrating complementary mechanical, biological, and metabolic processes within a single synergistic framework. The concept focuses on Neauvia Stimulate, a PEG-crosslinked hyaluronic acid (PEG-HA) filler enriched with calcium hydroxyapatite (CaHA), which intrinsically embodies two “cores”: the mechanical core providing immediate structural lift and the biological core inducing progressive dermal regeneration. To reinforce deep anatomical support, Neauvia Intense may be used concomitantly as a structural scaffold, optimizing the environment for superficial and mid-fat layer regeneration. Drawing on histological, clinical, and biochemical evidence, this model illustrates the evolution of aesthetic medicine from volumetric correction toward physiological bio-regeneration, emphasizing precise anatomical targeting and the “less-is-more” principle of natural tissue restoration. This integrative approach represents a paradigm shift from static correction to functional, multi-layered rejuvenation aligned with the physiology of facial tissues.

Skin aging reflects the accumulation of molecular damage and a progressive disruption of dermal mechanical homeostasis. Fragmentation and disorganization of the dermal extracellular matrix (ECM) impair force transmission to resident fibroblasts. Reduced cell spreading and mechanical force generation are associated with increased matrix metalloproteinase expression and reduced collagen synthesis, partly through c-Jun/AP-1 activation and attenuation of TGF-β/TβRII signaling. Reduced YAP/TAZ mechanosignaling has also been linked to cGAS-STING-dependent senescence in experimental models. However, its causal role in aging human dermis remains unresolved. This narrative review considers dermal mechanobiology as an integrative framework alongside ultraviolet exposure, oxidative stress, glycation, and cellular senescence. It examines how injectable fillers may influence the dermal mechanical microenvironment. A filler’s material properties may constitute a mechanical exposure, although bulk rheological measurements do not define force transmission at the cellular scale. Human in vivo studies of cross-linked hyaluronic acid provide the most direct evidence that enhanced structural support is associated with fibroblast spreading, activation of TGF-β-related signaling, and increased type I collagen deposition. Evidence for calcium hydroxylapatite and other biostimulatory fillers is complementary but more heterogeneous. A composite of PEGDE-cross-linked hyaluronic acid and calcium hydroxylapatite microspheres is considered as an explicitly preliminary example. This review defines the current evidence, its key limitations, and the mechanistically informed studies needed to determine whether, and which, fillers can meaningfully modify dermal mechanobiology.

Age-related deterioration of the dermal extracellular matrix is driven primarily by fibroblast dysfunction, leading to loss of collagen integrity, elasticity, and structural support. In aesthetic dermatology, injectable and biostimulatory interventions increasingly target qualitative dermal remodelling, with collagen reorganisation widely adopted as a histological endpoint. Picrosirius red (PSR) staining under polarised light remains the most frequently used method for visualising collagen architecture; however, its birefringence colour patterns are often misinterpreted as proxies for collagen subtype shifts, particularly between types I and III. This conceptual review examines the methodological basis of such interpretations. We summarise the biological roles of major dermal collagens and compare current histochemical, immunohistochemical, ultrastructural and molecular methods for collagen assessment. We propose an interpretative framework that separates architectural collagen remodelling from molecular collagen synthesis and addresses the temporal dissociation between early fibre reorganisation and later subtype-specific expression as a plausible explanation for between-study discrepancies. Practical guidance is provided to support responsible interpretation and reporting of PSR-based collagen analyses. PSR is best regarded as a complementary tool for assessing collagen architecture rather than a definitive method for collagen subtype identification.