## 4 Discussion
Therefore, the effects observed on leg and forearm contributed to showing the ability to achieve the desired outcome with flexibility. The research's pragmatic nature can be criticized as emulsion compositions were introduced as a second variable. The adaptation of the skin feel to each geographical region could be considered as a bias in analysis and prevents comparing the results between the data sets. However, testing a formula that corresponds to realistic conditions is equally important. Indeed, evaluating the effects of a formula that would contain 20% of a \"heavy\" oil with a long fatty chain in a country where the proposed formulations instead contain 10% oils with a lighter touch due to a hot and humid climate, could lead to a misleading conclusion disconnected from reality. Different oil compositions associated with different doses of stabilizing polymer resulted in different viscosities. However, a pronounced shear thinning profile, supported both by the glucolipid emulsifier and stabilizing rheology modifier, suggested a minor impact on spreading properties. As illustrated by the examples of flowing profiles in Figure 9a, viscosity of the emulsions subjected to shear, regardless of its value when the formula is in its packaging, was below 100 mPa-s when the shear rate exceeded 100 s\({}^{-1}\), which is representative of the shear applied when spreading on skin [44]. This is the case with all the oils studied and is even reinforced when the dose of stabilizing polymer increases (the examples here represent the lowest polymer concentration). In addition, this shear thinning characteristic is stable over time, as illustrated in Figure 9b. This pronounced shear thinning profile associated with a low thixotropic character (i.e., quick recovery of viscosity initial value, visualized in Figure 9 by the gap between up and down ramps) suggests an easy and even distribution at the skin surface with no difference between the studied emulsions [45]. Emulsion viscosity was also reported to have no effect on moisturizing properties (skin capacitance and TEWL measured on hand) in a previous study using acrylate-based polymers of different natures and at different concentrations [46]. Figure 9: **(a,b)** Emulsion flowing profiles at 25 \({}^{\circ}\)C using a controlled stress rheometer (AR 2000; TA Instruments, New Castle, DE, USA; cone-plate geometry 4 cm/2\({}^{\circ}\); 2 min shear rate ramp, 1 min at maximum shear rate before down ramp); **(a)** Measurements conducted after 7 days of storage at room temperature on two examples of simple emulsions. Viscosity is expressed as a function of shear rate; **(b)** Comparison of measurements after seven days and one year after storage of one example of simple emulsion to show the stability of the shear thinning profile expressed by the evolution of the shear stress as a function of the shear rate. On the contrary, the impact of variations in the oil phase composition cannot be ignored [26; 47; 48]. The four emoliments are not expected to provide strong occlusive properties as described for mineral and silicone oils with a high molecular weight [2; 3; 11; 49] but partial occlusive effects cannot be excluded. Caprylic/capric triglyceride could be classified as occluted by some authors [11] while esters were generally reported to act by filling the spaces between corneocytes leading to smoother skin [4; 11; 50]. The characteristics of the four emoliments in Table 4 seem to converge to suggest a greater penetrating ability for isononyl isononanoate followed by coco-caprylate/caprate and the resulting lower propensity to maintain a continuous film over the skin surface. Molecules with a low molecular weight, low viscosity and low polarity tend to penetrate more easily in the stratum corneum [51]. Results reported by [PERSON] et al. [51] showed a linear correlation between emolient penetration volume and improvement of the stratum corneum's mechanical properties (i.e., with an emolient softening role) but did not show data supporting the direct correlation with TEWL.