Wrinkles? What's the cause?

The first wrinkles usually appear around the mouth and eyes. Hereditary obviously plays a part but just how well our skin ages is mostly due to our lifestyle.
The worst culprit is sun damage. UVA and UVB rays penetrate the deepest layers of the skin, breaking down collagen and elastin that are the skin's support structures.
Collagen makes up 70% of skin and is the main structural protein, giving skin strength and maintaining elasticity; without it, skin creases and wrinkles more easily. It's also a vital component of tendons and bones. Elastin is the other main fibrous protein giving skin its bounce. Collagen and elastin are in turn produced by fibrolasts, the most common type of cell in connective tissue. The  number and activity of bibrolasts drop as we age.
As collagen is broken down and damaged, the ageing process accelerates. The less collagen we have, the more other factors start to have an impact. Habitual facial expressions etch themselves into lines as the skin loses its ability to bounce back. Frowning may or may not use more muscles than smiling, but furrowed brows lead to deep-set "elevens" above the bridge of your nose.
Natural collagen and elastin production also declines with age but there are certain lifestyle factors that can speed up the process.
Free radicals are unstable oxygen molecules that damage cells and slow the production of collagen. They are thought to be a key factor in the ageing process. Sunlight, smoking and air pollution all add to the production of free radicals.
Smoking can reduce collagen by up to 40% and as it also restricts blood flow to the skin, robbing it of nutrients and oxygen. Wrinkles can start appearing on the faces of smokers as young as twenty. Lines tend to be deeper, skin has a coarser texture and less healthy colour so that by the age of forty, smokers often have as many wrinkles as non-smokers twenty years older than them.
Hormones also play a part. Reduced levels of oestrogen as we age may decrease collagen levels by 2% a year.
Hyaluronic acid is a naturally occurring component of skin which helps hydration and elasticity. It also removes toxins, supplies nutrients and supports collagen and elastin. It effectively moisturizes skin from the inside, guarding against wrinkles, but levels fall over time as a result of ageing and the effects of sunlight and pollution.
Stress, pollution, allergens, sunlight and poor diet all cause inflammation which shows itself in the body in stiff, aching joints, irritable bowel syndrome and illnesses such as sinusitis. On the skin, inflammation results in wrinkles and other signs of premature ageing.