Life by Design

Intrinsic and extrinsic skin ageing Skin ages intrinsically (chronologically from within) and extrinsically (due to external factors). Intrinsic skin ageing results from the passage of time and is mainly due to the action of reactive oxygen species (ROS) (Box 1) (Naidoo and Birch-Machin, 2017). It occurs within the skin itself due to reductions in dermal mast cells, fibroblasts and collagen production, and a flattening of the junction between the epidermis and dermis. Intrinsically aged skin is unblemished, smooth, pale, dry and less elastic with fine wrinkles (Landau, 2007). The fact that it covers the entire body means the skin is the most obvious place to observe signs of ageing. The skin is the body’s largest organ – an average adult’s skin has a surface area of approximately 1.67m² and weighs around 4-5kg (Marieb and Hoehn, 2015). Skin is a malleable but tough structure, serving as a bag holding in all the body’s contents; without it, we would quickly succumb to water and hea...