A wrinkle is a deep break in the collagen and elastin fibres. It is caused by the constant movement of the skin so it is seen in mobile areas such as around the mouth, at the corners of the eyes and on the forehead. These are the main points that inevitably move when we speak, express joy, sadness, denial etc.

Skin cells need first of all oxygen in order to feed and produce new collagen and elastin. Oxygen is carried into our body by inhalation and distributed through the bloodstream to all body tissues, including the epidermis. At the point where the skin is wrinkled by our grimaces the blood flow stops abruptly so the cells there are not oxygenated and as a result collagen and elastin are weakened and the mesh in these areas breaks down.