Understanding the life cycle of skin

The life within your skin

We all have a tendency to take healthy skin for granted and underestimate its importance for our overall wellbeing. We only really notice it when something changes – whether it's a minor blemish, aging, a skin condition or disease.

But our skin is a natural wonder. It protects against infections and UV radiation, regulates our body temperature and helps us touch and feel the outside world.

It also helps us to understand each other. Whether it’s the flush of embarrassment, the pale look of fear or the off-colour pallor of someone coming down with an illness, we learn so much from each other’s skin.

It is also home to billions of living microorganisms and bacteria, many of which enable us to function as we do. As we learn more about them, we are seeing how vital they are to our overall wellbeing.

Dive beneath the surface and it becomes clear just how complex and alive our skin really is.

Regeneration rate

Human skin consists of three layers: the epidermis, the dermis and the subcutaneous tissue.

The epidermis is the outer layer, which undergoes constant renewal; every 28 days all cells are turned over as the most superficial cells are replaced by new ones. The turnover is much faster for infants and slows down over the course of our lifetime.

The healing process also slows as we age. The cuts, grazes and bruises that disappear quickly when we are young linger as the skin needs longer to repair itself, so dealing with them quickly can help us heal faster.

Going deep

The second layer - the dermis - contains blood vessels, which carry oxygen and vital nutrients around the body and take waste products away. It also has elastic fibres, collagen to maintain flexibility, nerve endings and sweat glands to help regulate body temperature.

The skin’s third layer, the hypodermis, is home to larger blood vessels and nerves and is made up of fatty and connective tissues. It also acts an insulator which further helps regulate temperature.

We’ve understood these layers for some time. What we’re only just discovering is the importance of what lives on our skin and inside our gut - a “community” of microorganisms known as the microbiome.

Playing host

There are thought to be about 100 trillion bacteria and other microbes living on or in us - including mites and viruses.

While research into the microbiome is relatively new, scientists believe it could influence everything from our behaviour to the illnesses we suffer from.

Imbalances in the microbiome have been linked with diseases ranging from eczema and asthma to diabetes and obesity.

Most research has focused on the gut, but there are plenty of microbes that inhabit our skins, including fungi and mites.

Skin flora

Our so-called “skin flora”, often offers many benefits, such as consuming harmful micro life. In the gut and lungs, evidence has shown that microbes can stimulate the immune system, but it is not yet known if this is also true for those on the skin.

However, some microbes can cause or at least be involved in skin problems, including ringworm and candida, which usually clear up quickly with medication. However, for people with immunity problems, skin complaints can sometimes turn into life-threatening conditions such as Pemphigus vulgaris.

Scientists say that an unbalanced diet can upset the microbiome of the gut, and some think that upsetting the life on our skin could just be as bad.

Exposure to exhaust fumes, smoke, cleaning fluids, cleansers and the daily pollution of modern life can seriously impact the skin. Clean air is not just important for our lungs.

A guide to skin maintenance

Drinking enough water and eating foods with plenty of vitamins and antioxidants can also help keep our skins healthier.

And keeping skin clean, rinsing the face twice a day, and maintaining a healthy diet is good advice for most of us.

But as our skin ages, it changes. Being prepared for this, and trying to enjoy the changes, can help us worry less about the process, but for each of us it will be different.

Our skin looking less youthful and feeling rougher and dryer, are to some extent inevitable processes, but there are some things we can control: not smoking, not drinking excessively, taking regular exercise and enjoying a healthy diet can slow down the whizzing biological clock.

Reducing our exposure to the sun also helps as there is no such thing as a “healthy” suntan. Some experts say that we would not develop wrinkles until we were in our 80s if we did not have so much sun exposure. This is even more important for those with lighter skin tones and those exposed to higher levels of UV.

If you decide to use skin care products, such as cleansers, moisturizers and exfoliants, make sure the ones you choose are right for your skin type.

Consult a dermatologist if you notice any changes in your skin or if you have any concerns about how it is aging.

Finally, consider your microbiome. Learn to love the life within your skin and ensure you take care of something which does so much to take care of you.

To find out more about your skin, check out the dedicated section


This story is part of a series of articles aiming at illustrating how healthy skin makes a positive impact on people’s lives. It has been developed with the contribution of our scientific and medical experts and is intended for a general public.