As we age, skin cells divide more slowly, and the inner skin (or dermis), starts to thin. Fat cells beneath the dermis begin to atrophy, and the underlying network of elastin and collagen fibers loosen and unravel. Fat cells provide “scaffolding” for the surface layers, skin begins to visibly lose its elasticity. When pressed, it no longer springs back.
The skin’s ability to retain moisture also decreases as the sweat and oil-secreting glands become less productive. Skin becomes drier and is slower in repairing itself.
Facial expressions–or dynamic motion–also cause permanent creases over time. Frown lines (those between the eyebrows) and crow’s feet (lines that radiate from the corners of the eyes) develop because of repeated small muscle contractions and habitual facial expressions form characteristic lines.
The degree of wrinkling depends on your genetic makeup, but smoking, dry skin and sun exposure (especially sunburns) make it worse. In fact, exposure to ultraviolet light, UVA or UVB, from sunlight accounts for 90% of the symptoms of premature skin aging. And most of the photoaging effects occur by age 20, even though it may take years to see it.