# Unveiling the Role of Minerals and Trace Elements of Thermal Waters in Skin Health
## 2 Minerals, Trace Elements, and Other Compounds of TSW in Skin Health
### Anions
#### 2.1.2 Sulfate  
[PERSON] et al. [64] revised the medical use of sulfate mineral waters, including in treating skin disorders, citing the expression of [PERSON] (expert on thermalism in dermatology), who coined the term \"mineral eudemic water\" to identify waters able to provide an organism with all the factors necessary for nutritional, eutrophic, and rehydrating action. In this review, the authors highlighted the effects of sulfate mineral water stimulating skin turnover and toxin removal, and several types were cited as sodium-chloride sulfate, magnesium-sulfate, carbonate-sulfate alkaline, carbonate-sulfate-calcium, and bicarbonate-sulfate-rich mineral waters.  
One of the most studied sulfate-rich spring waters is Uriage thermal spring water (Uriage TSW), which is also rich in chloride, sodium, calcium, magnesium, silica, and trace elements. [PERSON] et al. [26] investigated the effect of Uriage TSW on skin protection by evaluating taurine transporter (TauT) and sodium-dependent vitamin C transporter 1 (SVCT1) expressions in normal human keratinocytes at a basal level and under stressful conditions (irradiation UVB). Keratinocytes were incubated with Uriage TSW at increasing concentrations after irradiating the cells with UVB, and the effect of UVB was slightly reduced after 24 h, and a high level of TauT expression was maintained after 72 h. The results showed that the Uriage TSW slightly reduced the effect of UVB after 24 h of incubation but permitted the maintenance of a high level of TauT expression after 72 h of incubation. The authors suggested that Uriage TSW could act to efficiently protect the skin from dehydration through its effect on TauT and SVCT1 expression and additionally permit a more efficient taurine and vitamin C supply to the epidermis in order to protect it from other aggressions such as oxidant stress. In addition, the UTSW could also be useful for the skin in fighting against situations such as dehydration, UVB irradiation, and aging.  
Other in vitro studies performed by [PERSON] et al. [17; 18] investigated the effects of a cosmetics cream formulated with Uriage TSW. In the first study, the Uriage TSW cream showed a very good effect on _stratum corneum_ reparation, and the filaggrin labelling and AQP-3 labelling were equivalent to that observed in control explants. The results showed that this formulation was also able to enhance the expression of claudin-4 and claudin-6 in the delipidated explants, and the authors concluded that the use of Uriage TSW in cosmetic formulations contributes to increasing their efficacy in treating dry skin conditions. The second study focused on an evaluation of the protective effects of Uriage TSW on skin barrier function, investigating its antioxidant properties through TBARS and SOD activity assays. The Uriage TSW was able to reduce the lipid peroxidation induced by HX/XO (xanthine oxidase (XO)/hypoxanthine (HX) free radical) stress and also to restore the reduction in skin claudin-6 expression when skin explants were exposed to UVA +UVB radiation. These results demonstrated the antioxidant and DNA-protecting effect of Uriage TSW.  
Later studies investigated UTSW in _C. acnes_ biofilm formation. One study evaluated the effect of catecholamines on acneic (RT4) and non-acneic (RT6) strains of _C. acnes_ in a medium with Uriage TSW compared with sterile physiological water. On strain RT4, grown in a sterile physiological medium, the biofilm formation was studied after exposure to epinephrine; the results showed a significantly lower basal biofilm production with Uriage TSW compared to a medium containing sterile physiological water [19].