Regulation of the aging process is largely genetic. Our intrinsic aging speed is determined by hereditary factors, and individual response to aging accelerants in the environment. The number one culprit being sunlight. All together these factors are responsible for the individual pace of aging. At some point, the machinery simply wears out, the skin loses its resilience, elasticity and luster and the signs of aging appear. That point becomes increasingly philosophical as science edges forward and aging is pushed farther along the curve. The first step in prevention is getting to the bottom of what one is trying to prevent.
At the most basic level there is a great deal of evidence that aging of living organs is regulated by a tail at the end of each chromosome called the telomere. With each cell division the telomere shortens. When it is shortened below critical length, the cell wears out, ages and dies. Maintaining telomere length is the secret to eternal youth of the cell and scientists working with gene-altering techniques have managed to introduce the enzyme that protects telomere length into experimental situations. Putting this into practice is another matter.
Other studies have found that severe calorie restriction encourages longevity on the cellular and organism level. This has been proven repeatedly in mice and, in July 2009 graphically demonstrated in monkeys. Few are able to live so ascetic a life as necessary to effect the change, but a chemical in the skin of grapes and in red wine called resveratrol, seems able to mimic the cellular benefits of severe calorie restriction, greatly increasing life span and physical well-being. The trouble is no one knows how much resveratrol is necessary to do the job. Laboratory mice demonstrated dramatic objective rejuvenation after being fed enormous amounts of the resveratrol. Who knows how much humans would require. Nonetheless, resveratrol supplements are flooding the market, and a lot of smart people are taking it despite the probability that the dose is quite insignificant.
These factors affect the body as a whole and all organs, including the skin. There are genetic, chemical and mechanical causes for the visible changes that we think of as aging of the skin, and until we can control the underlying cellular biology our only avenue is to deal with the external factors within our control. In this manner we can prevent accelerating the predetermined aging cycle. In the meantime avoiding sun damage, using antioxidant serums to reverse sun damage, good nutrition, exercise, and not smoking are the most basic and effective preventative steps you can take. They work.