## 4 Discussion
Skin aging is the result of complex genetic and hormonal processes, as well as exposure to UV radiation and environmental pollutants, which leads to a gradual deterioration of the skin's condition [36]. The increase in skin hydration in each of the tested groups resulted from the presence of emollients in the composition of the creams, which retain moisture in the stratum corneum through occlusion. This, combined with regular use of the preparation, contributed to the improvement of skin hydration. [PERSON] et al. [6] also assessed the effect of a cosmetic cream containing an extract of powdered common bean seeds (_P. vulgaris_) on skin hydration. They observed that, both after applying a placebo cream and a cream with an extract of powdered bean seeds, there was a significant change and the skin became moisturized. They concluded that this increase in moisture content in the stratum corneum was caused by the presence of vitamin C in the extract and the presence of fatty acids in the cream base of the cosmetic, which have a moisturizing effect. The influence of various factors on skin hydration was also demonstrated by [PERSON] et al. [37]. They used the Corneometer(r) probe to measure skin hydration. They showed that skin hydration decreases significantly with age as part of the natural aging process, which is a consequence of both internal aging processes and external factors such as sun exposure and environmental pollution. This research highlights the importance of maintaining skin hydration as a key factor in the aging process. [PERSON] and co-authors [30], in their study, assessed the influence of skin hydration on the formation of wrinkles. They used both the Cutometer(r) and Corneometer(r) CM 825 probes. They showed that lack of proper skin hydration leads to reduced skin elasticity, resulting in the faster appearance of wrinkles, while maintaining an appropriate level of skin hydration delays the aging process. Skin elasticity, determined by elastin and collagen fibers, is a key indicator of its viscoelasticity. As the skin ages and under the influence of various external factors, the structure of these fibers becomes more rigid, leading to skin sagging and the formation of wrinkles. Therefore, measuring skin elasticity serves as an important indicator of its biological age [38]. The skin elasticity parameters studied enable the analysis of age-related changes and the evaluation of cosmetic efficacy [27, 28]. For skin elasticity testing, the Cutometer(r) probe is most commonly used [29]. The skin phototype primarily depends on the pigment content, including hemoglobin and melanin. It is an important indicator of the skin's response to UV radiation and certain chemicals, including drugs [33]. The Mexameter(r) MX 18 probe uses different wavelengths to measure the content of hemoglobin and melanin in the skin. The measurement results are expressed as the Erythema Index (EI) and the Melanin Index (MI) [34]. The Mexameter(r) probe provides reproducible and highly precise measurements, with minimal impact from environmental variables [35]. The brightening effectiveness of our cream with an extract of common bean (_P. vulgaris_) was comparable to the reference cream. The brightening effect of this type of cream was also confirmed in studies by [PERSON] et al. [6]. The participants' skin did not exhibit features characteristic of vascular skin. Therefore, while a reduction in erythema was observed, it did not reach statistical significance. With respect to the sebostatic effect, no statistically significant differences in sebum levels on the skin surface were observed between the study groups. This is likely because the average age of the participants was 51.8 years and none had oily skin. At this age, reduced sebum secretion is natural and typical, which likely made any sebostatic effect of the cream with the extract neither visible nor necessary. The cream with micellar extract from common bean sprouts demonstrated high efficacy in skin hydration, improving elasticity and reducing discoloration.