Theories of ageing at a glance: how skin ages

Good skin plays a big role in your appearance. It’s one of the first things people notice about you. Skin care is a two-billion-dollar industry, and advancements in research on the topic are constantly evolving. From wrinkles to age spots, there is a lot of talk about why skin changes with age, and no shortage of theories when it comes to skin ageing.

Considering its importance, researchers are always learning more about why skin ages and how to slow down the ageing process. Outdated theories claimed skin changes are genetically determined (this theory has mostly fallen out of favour), while modern theories focus on how lifestyle choices like pollution, diet, and sun exposure affect skin age.

Researchers are constantly testing theories to get to the bottom of how skin ages. Many ideas overlap, or only represent one piece of the puzzle. Together, they create a picture of how ageing may occur as a whole.

Today, we will look at the four most important skin ageing theories:

Oxidative Stress Theory

Let’s start with one of the most widely accepted schools of thought regarding how skin ages. Oxidative Stress Theory says that as free radicals build up in the body, they damage cells, which results in ageing.

Normal biological functions produce free radicals, and the body has ways to process and eliminate them. However, external factors like smoking, poor diet, sun exposure, and pollution also create free radicals in the body. When too many free radicals build up, cells are damaged.

Skin cells, for example, become damaged and inflamed trying to keep up with free radicals. Skin cells that are exposed to too many free radicals wear out quickly as they scramble to process and eliminate them. As a result, skin cells weaken, changing the structure of the skin, and allowing wrinkles and fine lines to form, among other signs of ageing.

Cell Senescence Theory

Do skin cells die after they have divided one too many times? Cells are not immortal! They eventually stop dividing, ultimately reaching what’s known as senescence.

In 1961, scientist Leonard Hayflick proposed that human cells can only divide about 50 times before they call it quits. After that, cells are unable to carry out essential functions and tissue quality diminishes. Skin cells no longer function as effectively, which leads to an aged appearance.

Experts who stand by this theory say that one of the best ways to slow down ageing is to reduce the speed at which cells divide. Researchers are looking into ways to do just that. In one recent study, lab tests showed that reducing calories caused cells to divide slower, which helps cells stay healthy and active longer, thereby slowing down ageing.

We can also look at collagen production. Collagen is essential for youthful-looking skin. When the skin’s epithelial cells undergo too many cell divisions, they can no longer effectively produce collagen. Without collagen, skin loses firmness and elasticity, a hallmark of that tired, aged look.

Cross-linking Theory


Diet choices contribute to skin ageing. Cross-linking Theory experts say that eating simple sugars makes can cause ageing. When the body digests glucose, it binds to protein molecules in a process known as glycation. Glycation occurs in cells throughout the body, and skin tissue is no exception.

Collagen, the building block of skin, is affected most. When glycation occurs, collagen fibres become inflamed and stiff, leaving them unable to carry out essential functions for maintaining healthy, strong skin. Elastin, which gives skin elasticity and bounce, has a similar reaction.

As a result, skin structure weakens which causes sagging and wrinkles to develop. Avoiding sugary and high glycaemic foods can effectively slow down the ageing process, according to this theory. Antioxidants are also important for offsetting the damaging effects of glycation, both in skin care products and in your diet.

Photoageing Theory

Photoageing in many ways falls under the oxidative stress theory we mentioned earlier, but the sun is such a huge factor in ageing that it deserves its own discussion. Yes, you’ve heard a million times that sun protection is super important for keeping skin healthy, and experts can’t emphasise this enough. There’s good reason!

Study after study links sun exposure to premature skin ageing. Photoageing Theory says that 80 percent of ageing is caused by sun exposure alone. For one thing, UV light from the sun contributes to free radicals in the skin. This causes oxidative stress, which harms skin cells.

UV light also damages collagen and elastin in skin, which leads to wrinkles, fine lines, and sagging. In addition, the sun can give skin a leathery or thick appearance with too much sun exposure over time. Freckles and age spots may also form. The sun is really capable of harming the skin in so many ways.

There are many theories of skin ageing. Some compete with each other, and others may very well occur simultaneously, complicating the matter. The answer is that skin ageing is not simple, and there are many factors internally and externally that promote skin ageing.

So what can we do to slow skin ageing and maintain youthful skin? It is recommended to always use sunscreen, use topical antioxidants to protecting skin from free radicals, and avoid smoking and pollution when possible. A healthy, antioxidant-rich diet is always a good idea, and so is avoiding high-glycaemic and sugary, processed foods. Small changes like this can help skin look and feel its best.