The Science Of Tanning: What's Really Happening To Your Body

Reality check: tanned skin is damaged skin.

After a year of staying close to home, Brits are flocking to beaches and lidos on a mission to get their tan on as the summer weather hits in full force.

But what actually happens to our bodies when we sit in the sun for a bit too long and our skin darkens?

Many of us might see tanning as a safer way to catch some rays – after all, you’re not burning, so surely the damage can’t be that bad?

Unfortunately that’s not quite true. Tanning can age your skin – you might end up with sun spots, wrinkles and a more weathered appearance – and evidence suggests it greatly increases your risk of developing skin cancer, too.

What happens to our bodies when we tan?

Tanning of the skin is a complex process and has three different phases, according to dermatologist and British Skin Foundation spokesperson Dr Emma Wedgeworth.

The first phase is immediate pigment darkening (IPD) which happens directly when our skin is exposed to sunshine (or UV rays). IPD occurs as a result of a change and redistribution of pre-existing melanin – the natural pigment that is responsible for producing the colour in our skin, hair and eyes.

If you spot tan lines appearing after a few hours indoors, this can be attributed to the second phase of tanning: persistent pigment darkening (PPD). This occurs within a few hours of catching the sun and results from oxidation of melanin in your skin.

Lastly, delayed tanning (DT) occurs within days of UV exposure and is a result of increased melanin production and melanocyte activity. What are melanocytes, you ask? They’re the melanin-producing cells in the bottom layer of your skin’s epidermis, as well as other body parts including eyes and ears.

What damage is being done?

The reality is, tanned skin is damaged skin. When we sit in the sunshine, UV radiation penetrates the skin and leads to a number of growth factors and enzymes being produced – including the key enzyme tyrosinase, explains Dr Wedgeworth. This stimulates the production of melanin, which causes the skin to change colour.

The production of more melanin is basically a sign of damage in itself – and is the skin’s attempt to protect you from any further damage caused by the sun. According to the Skin Cancer Foundation, each time you tan, the damage builds up, creating more genetic mutations and a greater risk of cancer.

We know that lighter skin in particular is more susceptible to damage from the sun. Dark skin, on the other hand, is more efficient at dealing with UV radiation, explains Dr Wedgeworth. “It already has high levels of melanin and pigment-containing packages (melanosomes) and therefore darkens more quickly and easily and is less affected by UV radiation because the high levels of melanin absorb and reflects UV, preventing more damage deeper down in the skin.”

People with darker skin should still wear sun protection though – anyone, regardless of skin tone, can develop skin cancer as a result of too much sun.

“For people who experience redness and then tanning; this is a sign of DNA damage,”Dr Wedgeworth adds. “My advice is not to try and change the colour of your skin too significantly with the sun. The harder your skin has to work to produce melanin, the more damage you are doing.”

To avoid sun damage it’s best to keep out of the sun when it’s at its strongest, stay in the shade as much as possible, cover up with loose clothing and a hat, and protect your skin (including your eyelids) with skin.

When buying sun cream, opt for high sun protection factors (SPF) – and remember to regularly reapply it throughout the day.