The cutaneous effects of long-term use of Dead Sea mud on healthy skin: a 4-week study.

Purpose: To investigate the effects of various types of Dead Sea mud (DSM) on skin barrier properties over a period of four weeks.

Methods: The effects of a 4-week application of three types of DSM (as is mud, mud with extra Dead Sea salt, and over the shelf mud) on the barrier properties of normal skin were investigated. Preparations were applied onto forearms of healthy volunteers every other day for 4 weeks, and skin hydration, transepidermal water loss (TEWL), melanin, erythema level, skin pH, skin elasticity, dermal thickness, and collagen content were measured at predefined circular areas on subjects' forearms at baseline, week 1, week 2, and week 4 during the treatment phase and on week 5 following a 1-week regression period in which no mud was applied.

Results: The use of DSM for 4 weeks was well tolerated with no noticeable changes in TEWL, skin pH, melanin, and erythema levels. A slight firming effect was observed in the forearms treated with salted DSM. Skin hydration was not significantly affected by any type of DSM. However, a slight drying effect of "as is" and "salted" DSM and slight hydration effect of "over the shelf" DSM were observed. This effect could be attributed to the content of DSM rather than to disruption of skin integrity as confirmed by TEWL values.

Conclusion: Long-term use of all types of DSM did not compromise the barrier integrity of the skin. This provides dermatologists with needed information on safety of DSM and lack of skin disruption activity upon long-term use.