J. Cosmet. Sci., 69, 269–278 ( July/August 2018) 269 Skin Tolerance of Three Types of Dead Sea Mud on Healthy Skin: A Short-Term Study SAJA HAMED and ABDEL-MAJEED ALMALTY, Faculty of Pharmaceutical Sciences, Hashemite University, Zarqa, Jordan (S.H.), Faculty of Allied Health Sciences, Hahsemite University, Zarqa, 13115, Jordan (A.-M.A.) Accepted for publication July 10, 2018. Synopsis Dead Sea mud (DSM) is commonly used by patients with various skin conditions because of its contents of healing elements. No study was published to show whether DSM application weakens or strengthens skin barrier function. In this study, we investigated the impact of 30-minute single application of various types of DSM (“As Is” mud, mud with extra Dead Sea salt, and over-the-shelf mud) on the barrier function of normal skin. The infl uence of 30-minute application of various types of DSM was investigated noninvasively on skin barrier properties of healthy female adult volunteers (n = 75) on predetermined circular areas. Skin hydration, transepidermal water loss (TEWL), erythema and melanin levels, and skin pH were measured directly, 30 minutes, and 60 minutes after mud removal. Thirty-minute single application of DSM was well tolerated with short-lived moisturizing effects, which was enhanced by the presence of humectant ingredients, and with no negative impact on barrier integrity, pH, and erythema and melanin levels. INTRODUCTION In Jordan, numerous pharmaceutical and cosmetic manufacturers produce and distribute cosmetic and skin-care products worldwide based on minerals and mud from the Dead Sea. For thousands of years, the extraordinary water and mud of the Dead Sea were recog- nized as a natural treatment for patients with various cutaneous and rheumatic diseases. Balenotherapy is a well-known treatment modality in dermatology that involves immer- sion of the patient in mineral water baths with a high salt concentration for healing and recovery from a number of infl ammatory skin diseases such as psoriasis and atopic derma- titis (1). It has been documented that Dead Sea water and mud are effective treatments for patients with psoriasis, with excellent improvement exceeding 85% after 4 weeks of treatment (2). A signifi cant increase in the levels of serum Br, Rb, Ca, and Zn was noticed in psoriatic patients after daily bathing in the Dead Sea for 4 weeks, which may be partly responsible for the improvement of psoriatic condition (3). The mechanisms by which salty water alleviates these diseases have not been fully elucidated. However, natural Dead Address all correspondence to Saja Hamed at hamedsh@hu.edu.jo.

JOURNAL OF COSMETIC SCIENCE 270 Sea products use the power of Dead Sea minerals, specifi cally magnesium ion, which has been shown to play a key role in the anti-infl ammatory effect of Dead Sea water in both in vitro and in vivo studies (4,5). Dead Sea mud (DSM) masks are also popular at spa body sessions at Dead Sea spa centers and are a well-known component of a number of facial and body mask products manufac- tured by the cosmetic industry in Jordan. Dead Sea black mud is a blend of Dead Sea minerals and organic matters naturally formed over thousands of years on the bed of the Dead Sea (6). This unique product is rich in various minerals including magnesium, potassium, calcium, and chloride. DSM, whether from the Dead Sea shore or as an over-the-shelf product, is applied directly on skin for a designated period of time. To our knowledge, there is no published work regarding the effect of DSM on skin barrier properties. This fact, coupled with the wide- spread use of DMS, prompted us to initiate this study to evaluate, noninvasively, the short-term effects of various types of DMS on various skin properties (barrier integrity, hydration, pH, and erythema and melanin levels). MATERIALS AND METHODS MATERIALS Native DSM was generously provided by Numeira Mixed Salts & Mud Company Ltd. (Amman, Jordan) it was treated at our laboratory by removing stones. Three types of DMS were used in the study: 1. “As Is” mud was prepared by mixing 15 kg of the native mud (after removing stones) with 1,500 ml of distilled water to improve its spreadability. The mud was then auto- claved for 15 min at 121°C. 2 . Salted DSM was prepared by mixing 30 kg of the native mud (after removing stones) with 2,000 ml of Dead Sea water, followed by autoclaving the mud for 15 min at 121°C. 3. Over-the-shelf mud was bought from a well-known shopping mall in Jordan. The list of its ingredients is presented in Table I. Natrosol® 250 HHX (hydroxyethyl cellulose) was provided by Ashland, Inc. (Covington, KY) and used to prepare a gel at 2% w/w concentration in distilled water to serve as control in this study to account for the occlusion effect of the mud on skin barrier properties. STUDY DESIGN Healthy female adult volunteers (n = 75), aged 18–45 years (22.1 ± 5.8 years), participated in this short-term study after giving their informed consent. The study was approved by the Institutional Review Board (IRB) of the Hashemite University. The participants were divided randomly into three groups of 20 subjects and one group of 15 subjects. Each group (n = 20) Table I In gredient List for Over-the-Shelf Mud DSM, water, aluminum silicate, glycerin, monopropylene glycol, ethanol, PEG-40 hydrogenated castor oil, preservatives, and fragrance.