## 4 Discussion
[PERSON] and [PERSON] have previously established a link between skin hydration and viscoelasticity, highlighting that increased water content influences the viscosity of interstitial fluid and the structural integrity of proteoglycans [12; 15]. This relationship is critical, as it provides insight into how hydration contributes to improved skin biomechanical properties. Additionally, other studies confirm that the R6 parameter is directly dependent on hydration levels in the skin [16; 17; 18]. [PERSON] et al. identified a strong correlation between R2 (gross skin elasticity) and age, whereas R6 (\"viscoelasticity\", focusing on the ratio of elastic to viscous deformation) demonstrated only a weak association with aging. This distinction suggests that the R2 parameter is more reliable for assessing skin aging compared to R6, providing a clearer representation of age-related changes in skin biomechanical properties [19]. Our findings are consistent with these observations, as no correlation was detected between skin viscoelasticity (R6) and participant age in our study. Additionally, previous research has noted that changes in the R2 parameter tend to be more pronounced with aging than those in R6, further supporting our results [20]. In our study, carboxytherapy alone and in combination with acids resulted in significant improvements in viscoelasticity, supporting existing research on the positive effects of this treatment modality on skin biomechanical properties [7; 8; 9]. Building on these findings, it is essential to explore the nuanced relationships between different skin biomechanical parameters and aging. These results underscore carboxytherapy's potential as an effective intervention for enhancing skin resilience and elasticity, further amplified when integrated with complementary therapies. The ability of carboxytherapy to stimulate collagen synthesis has been confirmed in studies by [PERSON] et al., who utilized histological and morphometric analyses and demonstrated a significant increase in collagen fibers (41.44 \(\pm\) 4.50%) compared to the control group (37.44 \(\pm\) 3.87%) after a single application of carboxytherapy with observations conducted 60 days post-treatment. These findings highlight the capacity of carboxytherapy to induce the synthesis of dermal components, even after a single session. Additionally, demonstrated significant differences in the morphometry for collagen fiber. Interestingly, the study also observed that higher infusion rates and greater gas volumes may enhance collagen synthesis due to barotrauma. Further research is needed to establish standardized protocols and investigate the impact of individual patient characteristics on treatment efficacy [5]. [PERSON] et al. demonstrated carboxytherapy to significantly improve skin structure in various conditions of striae distensae (SD). Carboxytherapy alone or in combination with fractional CO2 laser therapy effectively reduced the length, width, and pigmentation of SD lesions while enhancing skin texture. The study highlighted that while combined therapies showed slightly better clinical improvement, the difference was not statistically significant, suggesting that carboxytherapy alone is a highly effective modality for dermal remodeling. Histological analysis revealed marked remodeling of the dermis, with compact, dense, and well-organized collagen fibers accompanied by increased elastic fibers [6]. In the study by [PERSON] et al., Orcein Giemsa staining demonstrated a statistically significant increase in elastin synthesis. Additionally, the impairment of cutaneous vascular networks, characterized by reduced microvasculature, is a hallmark of skin aging. In the same study, a significant increase in VEGF expression levels observed in the IHC analysis confirmed the effectiveness of carboxytherapy in treating and partially reversing skin aging, primarily through the promotion of angiogenesis. These findings collectively reinforce the role of carboxytherapy as a safe and minimally invasive method for skin rejuvenation.