A natural microbial ecosystem – the skin microbiome – forms on the surface of the skin. It acts as the first line of defense against pathogens, regulates skin pH, and maintains the skin's moisture balance. When the microbiome is in balance, the skin looks and feels healthy. When it is disturbed – due to stress, excessive washing, or aggressive products – sensitivity, dryness, or redness often follows.
Many immune-mediated diseases have become more common over the past half-century, especially in urban environments. One reason is the decrease in the biodiversity of living environments. When the body's defense system does not receive the microbial exposure it needs, the risk of developing immune-mediated diseases increases.