A smarter dermal filler: Antimicrobial protection and collagen stimulation with niacinamide.

Biological skin aging involves structural changes, including flattening of the epidermal-dermal junction and reduced collagen types I and III. Modern aesthetic medicine is shifting from volumetric enhancement toward regenerative dermal fillers, though risks of delayed inflammation or infection from post-procedural injections should be mitigated. Niacinamide is a well-established molecule that stimulates collagen synthesis, modulates inflammation and inhibits bacterial growth. We evaluated the biostimulatory, antimicrobial, anti-inflammatory, and safety profiles of a new niacinamide-enriched cross-linked hyaluronic acid dermal filler (HAR) compared to untreated controls and Belotero Balance® (commercial reference). Biostimulation was assessed ex vivo in human skin explants cultured for 8 days, using Masson's trichrome staining and collagen I/III immunostaining. Antibacterial activity against Gram-positive and Gram-negative bacterial models was assessed by monitoring growth, while anti-inflammatory properties were analyzed via TNF-α and IL-6 levels in LPS-stimulated macrophages. Safety and biocompatibility were evaluated against human dermal fibroblasts. HAR-treated explants displayed improved epidermal architecture and a denser collagen type I network. HAR inhibited bacterial growth (∼90% Gram-negative; ∼50% Gram-positive), significantly lowered IL-6 and TNF-α levels, and showed excellent biocompatibility with high fibroblast viability and minimal hemolysis. These findings highlight HAR as a multifunctional dermal filler combining essential structural support with regenerative, antibacterial, and anti-inflammatory benefits.