The eye of Former German Chancellor Angela Merkel is seen during a press conference in Berlin, Germany, Friday, July 19, 2013. (AP)

As we age, our skin not only becomes thin and weak but the muscle, bone, and fat that support it and plump it also decrease in effectivity, causing wrinkles.

Other factors that speed up the process include smoking, poor nutrition, sun damage, and pollution, in addition to physical movements such as facial expressions.

The wrinkles and fine lines exist in our faces during our youth, and we can see them when we create facial expressions, but they vanish. As we age, they become more permanent.

Professor Rachel Watson, executive director at the A*Star Skin Research Labs and Skin Research Institute of Singapore, says: “If you ask your friends to frown, some people will get a single line in the middle of their forehead, and some will get a double line because everyone’s anatomy is slightly different."

They become more visible during our 40s and 50s under the eyes and around the mouth. In our 60s and over, they appear all over the face. Facial expressions are not the only cause, since if you sleep on your stomach or in the same position every night, pressure on the face can become worse.

Zombie cells

Within the skin, a natural “microrelief” exists, but that decreases with age.

Michael Sherratt, professor of biochemistry at the University of Manchester, said: “It becomes accentuated with aging,” adding: “You get an increase in the depth of the lines you can see on young, healthy skin.”

The supply and abundance of fresh cells to the epidermis decreases with age, making the skin’s top layer thinner. In the underlying dermis, the amount of collagen, elastin, and substances like hyaluronic acid reduce the skin’s strength, elasticity, and ability as they become less.

Some scientists believe that wrinkles age the whole body in general, which is derived from the theory that aged skin contains more defunct, zombie-like cells.

These cells release chemicals fueling inflammation, which creates conditions from high blood pressure and diabetes, to the hardening of the arteries and cancer. Current and ongoing research is attempting to discover the extent of these cells.

Cigarette packs don't lie

Exposed areas of skin such as the face, neck, hands, and arms, are mostly the ones hit with wrinkles as a result of ultraviolet rays in sunlight exposure, which catalyze the breakdown of proteins and increase premature skin aging.

A few studies on twins show sharp differences in facial wrinkles when one smokes and the other does not. Much of the damage comes from tobacco smoke, with skin wrinkles as a visible sign of harm inflicted on similar tissues like blood vessels.

Even sucking on a cigarette creates skin creases and smokers often have lines around the mouth, including vertical lines over the top lip.

Watson explains: “When we think about facial aging, it’s not just the skin, there are changes to the subcutaneous fat, the musculature, and the bones. The skin on the outside is still there, but the elements that keep it rigid are also aging,” adding: “It’s everything that’s starting to deteriorate.”