CUTANEOUS EFFECTS OF DEAD SEA MUD 271 was used to test one type of the aforementioned DSM types and the fourth group (n = 15) was used as a control group to test the occlusion effect of the prepared Natrosol® gel. The exclusion criteria were as follows: subjects with dermatitis, erythema, psoriasis, skin cracking, or any lesions on their forearms subjects receiving any local or systemic treat- ments and subjects who were pregnant or lactating. Before baseline measurements, sub- jects were asked to refrain from using moisturizers on their volar forearms 1 week before the study and to wash their forearms during this week in a prescribed manner twice daily (morning and evening) with a regular soap supplied by the researcher to start with dry skin on both forearms. On the measurement day, subjects were asked to relax for 20 min in a controlled ambient temperature (22°C ± 2°C) and controlled relative humidity (45% ± 5%). Three circles were marked on the ventral aspect of each forearm. Circles on both forearms were used to measure the following skin barrier properties using the Multi Probe Adapter System from CK Electronics GmbH (Koln, Germany): (a) Skin hydration level using the Corneometer® CM 825 (CK Electronics GmbH) (b) Skin m elanin and erythema levels using the Mexameter® MX 18 (CK Electronics GmbH) (c) Transep idermal water loss (TEWL) as an indicator of barrier integrity using the Tewameter® TM 300 (CK Electronics GmbH) (d) Skin pH using the Skin pH-Meter® PH 905 (CK Electronics GmbH) Each volunteer served as her own control, and mud treated and untreated forearms were randomized among subjects in each group. On the study day, following the washout period, baseline values of the aforementioned skin barrier properties were measured. Then, 10 ml of the mud was applied using a feeding syringe and spread gently using a tongue depressor on the ventral aspect of the assigned forearm and left for 30 min. The amount of DSM applied in the study was found to be satisfactory to achieve good distribu- tion and a thick layer over the whole ventral aspect of the forearm on trials by the authors during study protocol development. The mud was then removed by gently washing the forearm with warm water and drying by gentle tapping with medical gauze. The same washing procedure and tapping with gauze were carried out for the untreated control forearm. The skin barrier properties on the predeter- mined circular areas were then measured directly, 30 min, and 60 min after mud removal. DATA ANALYSIS The measurements made for each parameter in each group were summarized as mean ± SEM. The data were subjected to statistical analysis in SigmaPlot version 11.0 (Systat Software GmbH, Erkrath, Germany) using repeated measures ANOVA to determine if there were differences among mud-treated versus untreated forearms then, multiple comparison procedures were used to isolate these differences. Values of p 0.05 were considered sta- tistically signifi cant. RESULTS AND DISCUSSION All volunteers reported that they had refrained from using topical products on both fore- arms 1 week before baseline measurements and washed them twice daily with the given regular soap according to the instructions.

JOURNAL OF COSMETIC SCIENCE 272 Figure 1. Skin hydration levels for forearms tre ated with “As Is” mud (n = 20) (A), salted mud (n = 20) (B), over-the-shelf mud (n = 20) (C), and gel (n = 15) (D) at the baseline, directly, 30 min, and 60 min after mud removal, compared with untreated forearms. Values represented as mean ± SEM. All types of DSM (“As Is” mud, salted mud, and over-the-shelf mud) caused a signifi cant increase in skin hydration values directly after mud removal compared with baseline val- ues, as shown in Figure 1. The improvements in skin hydration values in the mud-treated forearm measured directly after removal of “As Is” DSM and over-the-shelf mud were signifi cant (p = 0.002 and p 0.001, respectively) compared with the untreated forearms at the same time points (Figure 1A and C). However, the improvement in skin hydration level observed directly after removal of the salted mud was not signifi cant compared with untreated forearms at the same time point, as shown in Figure 1B. The gel-treated group also showed a signifi cant increase in skin hydration level directly after gel removal compared with the baseline value (p 0.001) and compared with the untreated forearm (p 0.001) at the same time point, as shown in Figure 1D. The positive increase in skin hydration from baseline values was in descending orders as follows: Gel (Δ18.45) over-the-shelf mud (16.41) salted mud (11.88) ~ “As Is” mud (11.11), whereas the positive increase in skin hydration from baseline values for the un- treated forearms that were just washed with tap water did not exceed Δ8.71. Thirty minutes post the mud application, the skin hydration level retuned to the baseline level for “As Is” mud, salted mud, and gel-treated forearms. It is noteworthy to mention