Heat-Treated Strains of Lactiplantibacillus Plantarum Skinbac™ SB01 and Bifidobacterium animalis spp. Lactis Skinbac™ SB05 Visibly Fight Aging Signs Both In Vitro and In Vivo

Background: The skin microbiome plays a crucial role in maintaining barrier function and preventing inflammaging. Heat-treated probiotics offer stability advantages for topical formulations while potentially maintaining bioactive properties. Objective: To evaluate the safety, molecular mechanisms, and clinical efficacy of heat-treated Lactiplantibacillus plantarum Skinbac™ SB01 and Bifidobacterium animalis spp. lactis Skinbac™ SB05 in reducing visible signs of skin aging. Methods: In vitro studies assessed cytotoxicity (MTT/LDH assays), Aquaporin-3 (AQP3) expression, and reactive oxygen species (ROS) production in Normal Human Epidermal Keratinocytes (NHEK). A 30-day open-label clinical study (n = 20 females, 18–70 years) evaluated three formulations (face cream, serum, and eye contour) using instrumental measurements of hydration, elasticity, density, and roughness parameters. Results: In vitro testing showed a significant increase in AQP3 expression (+22% ± 3%, p = 0.03) and a non-significant reduction in ROS levels (−33% ± 9%, p = 0.06) at 107 TFU/well, with no cytotoxicity observed. Clinical evaluation demonstrated statistically significant improvements: eye contour formulation achieved +10.5% deep skin hydration (p < 0.0001) and −11% average roughness (p < 0.0001); serum showed +28.7% immediate hydration (p < 0.0001); and face cream improved gross skin elasticity by +6.3% (p < 0.01). No adverse events were reported. An independent and methodologically distinct placebo-controlled study was included for contextual support and was not directly compared with the present trial; this study evaluated a related 1% postbiotic formulation and reported statistically significant improvements over placebo in roughness, wrinkle depth, hydration, and biomechanical parameters. Conclusions: This pilot study provides preliminary evidence that heat-treated L. plantarum SB01 and B. animalis spp. lactis SB05 formulations could safely improve skin hydration and reduce roughness parameters. While in vitro results show a significant increase in AQP3 expression and an exploratory (non-significant) reduction in ROS levels, larger controlled trials are warranted to confirm clinical efficacy.