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Why the sun damages your skin

We all know that we need to protect our skin from the sun’s damaging UV rays.

But how exactly does the sun damage your skin?

Our experts explain…

What is sunlight?

The sun gives of electromagnetic radiation; waves of energy which radiate into space. After just over eight minutes travelling through space, it arrives at our planet. A proportion of this radiation filters through the Earth’s atmosphere to warm our skins and lights our days.

The light which is visible to us is only part of the story. Sunlight also includes light which is not visible to the human eye – the longer wavelength infrared light and shorter wavelength ultraviolet light (known as UV).

The different types of ultraviolet light

Within the definition of ultraviolet light there are three types: A, B and C. The very shortest wavelength UV radiation is ultraviolet C (UVC), of which very little reaches the Earth’s surface.

Ultraviolet B (UVB) has a slightly longer wavelength and is the radiation responsible for sunburn. It is also necessary for Vitamin D synthesis.

Ultraviolet A (UVA) has the longest wavelength and some years ago was considered to be a safer form of UV radiation and, therefore, was commonly used in tanning beds. However, it is now known that both UVB and UVA radiation damages your DNA and, as a result, can cause skin cancer.

What happens when the UV rays hit your skin?

When UV light reaches your skin it harms the cells in your epidermis, including the collagen and elastin fibres. This damage triggers your body to produce more of the natural melanin pigment to protect your skin from further damage. It’s this pigment which gives you a tan.

However, this additional melanin only gives you the equivalent of a Sun Protection Factor (SPF) of 2 to 4, so it does not provide sufficient protection from further sun exposure. So, you should always use a minimum of SPF30, even if you already have a tan.

UV light (UVA and UVB) can also affect your DNA. If it damages the DNA in genes that control skin cell growth this can lead to skin cancer. Damage can occur when the UV rays directly hit the DNA in your skin. In addition, it is thought that the ultraviolet radiation can indirectly affect your DNA by generating reactive oxygen species (ROS) in your skin. These are molecules which can attack your DNA – and this damage can continue long after the sun’s gone down.

Ultraviolet radiation can also weaken your immune system and make your body less able to deal with potentially cancerous cells.

What problems can this lead to?


The most obvious result of too much sun is sunburn. When the cells in your epidermis are damaged by UV radiation (mainly UVB), your body increases the blood flow to those areas, causing a reddening of the skin and warm feeling. Your immune system will then send white blood cells to eradicate the damaged skin cells, it’s this process that causes your sunburn to peel and feel itchy.

It can take up to two days for the full extent of your sunburn to develop, so if you suspect you’ve had too much sun it’s imperative to stay covered up for the next couple of days until you’re sure your skin has healed.

If you suffer severe sunburn, where the skin blisters, or if you develop a headache, fever or chills, you should seek immediate medical attention.

Premature ageing

The damage inflicted upon the collagen and elastin in your skin by the UV rays, mainly UVA radiation, can lead to many symptoms of premature ageing (also known as photoageing), including:

  • Wrinkles and deep folds
  • Leathery skin
  • Loss of elasticity causing lax, sagging skin
  • Areas of darker pigmentation – known as age spots or liver spots
  • Spider veins
  • A ruddy, reddened complexion

Actinic keratoses

Also known as solar keratoses, these are rough patches of skin, usually on your face, forearms, hands, scalp, ears or lower legs, caused by sun damage.

The affected areas could look red, pink, brown or skin-coloured and might be flat or raised. They can be just a few millimetres across but can grow to a few centimetres wide. They are often sore or itchy.

While not a harmful condition in itself, there is a small chance that actinic keratoses could turn into skin cancer (specifically squamous cell carcinoma), so it’s important to get them checked out by your GP.

Skin cancers

Exposure to the sun is the most common cause of skin cancer. This can be because you’ve spent too much time in the sun over a number of years or because you’ve been sunburnt.

Sun exposure can increase your risk of both melanoma and non-melanoma skin cancer. It is often linked with non-melanoma squamous cell carcinoma but can also be a cause of basal cell carcinoma.

Skin cancer is becoming increasingly common as people are living longer and, therefore, have naturally spent more time in the sun. People who work outdoors, have pale skin or have had sunburn are more at risk.

The following are possible signs of skin cancer and in all cases you should have them checked out by your GP at the earliest opportunity:

  • Any changes to the skin, particularly if you notice a mole, birthmark or other area of pigmentation changing in size, shape or colour.
  • If a patch of skin becomes inflamed, scaly or crusty.
  • If an area of your skin oozes or bleeds for no obvious reason and doesn’t heal.
  • If you have a flesh coloured bump on your skin that grows in size and doesn’t go away.
  • If you have a spot on the skin which suddenly feels itchy, tender or painful.

Sunshine and vitamin D

The UVB radiation from sunlight does have some benefits for our health. It’s necessary to allow us to make vitamin D, which helps us to absorb calcium and phosphate from our food. These nutrients are essential for healthy bones, teeth and muscles.

However, this doesn’t mean that you should risk sun damage in order to raise your vitamin D levels. Vitamin D can also be found in your diet (from oily fish, red meat and eggs) and can be taken in the form of dietary supplements.

Protecting your skin and dealing with any damage

You should always keep out of the sun in the hottest parts of the day and protect your skin with suncream. This should be a minimum of SPF30 (to protect from UVB rays) and have a five star UVA protection rating. Find out more about staying sun safe.

If you have any medical concerns about changes to your skin, then you should see your GP immediately.

We can help you deal with the ageing affects of sun damage through treatments including chemical peels, botox injections, CACI, mesotherapy and laser facial rejuvenation.

Contact us online or call us on 0330 024 1300 to find out more about our free consultation service to review your skin and recommend treatments which can help to reduce the ageing effects of sun exposure.