Yin Yang is the name of a school of philosophy that emerged in China some 3,000 years ago. It is based on the understanding that the perfect Universe is a result of the balance created by two great opposing, but complemenary forces, Yin and Yang. Katie May interpreted the skin's endless cycle of cellular renewal against a background of challenge from environmental and lifestyle factors, in the context of this ancient philosophy.

You may recognise Yin as female and Yang as male, or Yin as dark and cool while Yang is light and hot, but Yin and Yang also represent physical states like acid and alkaline. The skin has a mildly acidic surface area - the acid mantle - with a pH in the region of 5,0. This is designed to protect the outer layer of the body from attack and invasion, and it is the environment best suited to the microflora of healthy bacteria that inhabit the skin surface. However external factors including pollution, soaps, shampoos and tap water can alter the pH balance, raising it into the alkaline sphere, thus weakening the skin's natural defences.

Katie understood that with proper care, the skin would maintain its protective acid mantle and defensive microflora of healthy bacteria, to remain in the perfect condition to be able to deal with all environmental assaults. An ardent advocate of healthy eating as part of any skincare routine, Katie's byline for Yin Yang Skincare, and her understanding of human skin is one in the same: Naturally Balanced Perfection.

The Yin Yang symbol, representing the ceaseless cycle of day into night, is a fitting logo for a skincare product philosophy based on the life-long cycle of cellular renewal that is the pattern of human skin.