Skin ageing is a fact of life; everyone will face it sooner or later. To understand how this process works, it is important to understand how the skin works.
The human skin consists of three layers, called epidermis, dermis, and hypodermis.
The epidermis is the outermost layer of the skin. This provides a waterproof barrier and creates your skin tone. This layer of skin is where dead cells are shed. Your skin is constantly renewed by itself by shedding the old and damage outer cells and replacing them with newer cells. This process keeps your skin look fresh and revitalized. Beginning in your mid-20s the skin cell renewal process slows down and as you grow older your skin doesn’t reflect light so well and it goes dull and have lack of glow.
The dermis, or middle layer of skin, is made up mostly of collagen (which makes skin firm) and elastin (which makes it flexible) which gets depleted in your skin and your dermis becomes weaker, thinner and less elastic. As a result, you may notice your skin sagging and wrinkling more easily.
Another important molecule in the dermis is HA (hyaluronic acid). The principle molecule responsible for binding and retaining water molecules, which gets depleted in the skin as we grow older thus resulting in loss of skin moisture which leads to dehydrated skin. Today, synthetically made HA is incorporated into different anti-ageing beauty and healthcare products. The hypodermis is the innermost and thickest layer of the skin. It is used mainly for fat storage and has connective tissue, so this storage also decreases with age adding on to the sagging of skin.
Aging, by the way, is the result of two biologically independent processes. The first is intrinsic or innate ageing, an unpreventable process, which affects the skin in the same pattern as it affects all internal organs.
The second is extrinsic ageing, which is the result of exposure to external factors, mainly ultraviolet (UV) irradiation, which is also referred to as photoaging. Unlike intrinsic ageing, it can be controlled because it is a result of environmental damage. Human skin is constantly directly exposed to the air, solar radiation, environmental pollutants, or other mechanical and chemical insults, which can induce the generation of free radicals.
Free radicals are basically unstable molecules produced by complex chemical processes in your body. Left to their own way, these free radicals go on to damage otherwise healthy cells in a process called oxidation. This is the same process that turns a cut apple brown or changes a copper roof from reddish gold to blue-green, so you can just imagine the way it can affect your skin.
When combined with the natural ageing process, we experience dead lifeless skin, uneven tones, blemishes, pigmentation, and wrinkles because of the daily damages our skin gets exposed to.
While intrinsic ageing as said is natural and inevitable, extrinsic ageing can be controlled up to a limit by taking care of ourselves. For example, like, getting rid of unhealthy habits like smoking and drinking, getting proper sleep on time and using sunscreen lotion. Also, there are various specialized skin care products and treatments which can provide control over your skin ageing.