What causes wrinkles is a story that involves all 3 layers of the skin. The epidermis, dermis, and subcutaneous tissue. And is their interaction that causes wrinkles to happen.
The epidermis is the outer protective layer. As cells called keratinocytes move from the bottom to the top of the epidermis they create a tough layer of keratin. At the top they fall off naturally. The dermis contains the connective elements: collagen which gives the skin its strength, proteins called glycosaminoglycans (GAGs) which give the skin its turgor (fullness / tightness), and elastin fibers which give the skin its elastic spring. The epidermis gets nutrients from the blood vessels in the dermis and interlocking structures on both sides called rete ridges help increase the area that can capture these nutrients. The lowest layer is the subcutaneous tissue which is made up of fat cells. These cells insulate and make the skin look smooth and full.
As we get older the epidermis become thinner and less effective at being a barrier. The thinner cells make the skin look noticeably thinner (so you can see veins more easily) and the loss in barrier function means moisture escapes rather than being kept in the skin. This causes dryness. Epidermis cells drop by 10% every 10 years and they also divide more slowly so the skin can’t repair itself as well.
The dermal layer not only thins, but also produces less collagen and the elastin fibers (for elasticity) simply wear out. These changes in the basic structure of the skin cause the skin to wrinkle and sag. The sebaceous glands which produce a kind of oil get bigger but produce less sebum, and the number of sweat glands decreases. Both cause skin dryness.
The interlocking structures called rete-ridges at the dermis–epidermis boundary flatten out not only making the skin less strong but also means less nutrients get absorbed which reduces the skin’s normal repair process.
In the subcutaneous layer the fat cells get smaller with age. This makes wrinkles and sagging more noticeable, as the fat cells cannot “fill in” the damage to the other layers. What was a flat playing field becomes a bumpy, ridged surface.
Anti aging treatments aim at some or all of these processes and help prevent or restore them.
Sun has a major impact on your skin. It is said that 90% of the symptoms of premature skin aging come from exposure to UV light, (UVA or UVB). Sun exposure thins the epidermis but also creates more dangerous issues like skin lesions. In the dermis, sunlight causes collagen to break down faster and creates abnormal elastin. Without going into a huge amount of biological steps this abnormal elastin short circuits collagen production and make sit les effective. It creates something called “disorganized collagen” aka solar scars. When this happens repeatedly wrinkles develop.
Free radicals roam the body and skin trying to capture electrons from other cells…in a form of chain reaction. It essentially breaks down the collagen. Sunlight, smoking, and exposure to air pollution all act in the same way..
It is thought likely that skin changes happen due to menopause or lower estrogen. There are no conclusive studies that give us definitive information about the balance between lower estrogen, sun exposure and normal aging. Although animal studies have apparently shown that low estrogen can cut collagen 2% skin thickness by 1% annually
Repeated facial expressions also have an effect. Yes this may sound odd and makes your Mum right when she said “Don’t make that face or it will stay that way” They can cause wrinkles as it loses elasticity. Frown lines and crow’s feet can develop as the tiny muscles in those areas permanently contract.
And lastly Newton’s favorite topic. Gravity. Unfortunately the lack of elasticity and general loosening of the skin is made more visible as gravity acts to pull everything down and so the skin sags more leading to jowls and drooping eyelids.
Your mission should you decide to accept it is to fight all these natural processes.