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.