Damage to the skin by repetitive washing

Area of Science:

• Dermatology and Skin Physiology
• Cosmetic Science and Formulation
• Biophysics of the Skin Barrier

Background:

• Skin barrier integrity is crucial for maintaining homeostasis and preventing exogenous insults.
• Wash solutions, particularly those containing surfactants, can disrupt the skin barrier.
• Understanding the impact of different surfactants on skin function is essential for product development.

Purpose of the Study:

• To investigate the skin damage caused by repeated use of two distinct wash solutions.
• To quantify changes in key skin barrier parameters following single and repeated washing.
• To compare the regenerative capacity of skin after exposure to different surfactants.

Main Methods:

• Evaluation of stratum corneum capacitative resistance, lipids, and transepidermal water loss (TEWL).
• Measurement of skin surface pH, laser Doppler flow, and skin reddening.
• Comparison of skin function parameters after single and one-week repetitive washing protocols with two surfactants (sodium lauryl sulfate and Geliderm).

Main Results:

• Significant alterations in skin function parameters, including increased TEWL, were observed even after a single wash.
• Repetitive washing for one week led to further deterioration of TEWL and corneometry values, with sodium lauryl sulfate showing a more pronounced effect.
• Despite quantitative differences in surfactant effects, complete prevention of damage was not achieved with a milder surfactant, and skin regeneration rates were similar for both.

Conclusions:

• Repeated washing with common surfactants significantly impairs skin barrier function.
• Even milder surfactants can cause cumulative skin damage, highlighting the need for careful formulation.
• The rate of skin barrier recovery is not significantly influenced by the choice between the tested surfactants after repetitive washing.