What is the difference between UVA and UVB?

UVA and UVB are two types of light radiation that can cause
skin cancer.

Ultraviolet A (UVA) has a longer wavelength, and is associated with skin aging.

Ultraviolet B (UVB) has a shorter wavelength and is associated with skin burning. UVB is also responsible for making vitamin D.

Both UVA and UVB damage the DNA in skin cells, which lead to genetic defects and mutations which can cause skin cancer. Damage from UV exposure increases your risk of skin cancer over time. Your body may repair some of this DNA damage, however, the unrepaired damage and mutations may build up over time increasing your risk of skin cancer and melanoma. The amount of damage depends on a number of factors.

Women with red sunburned shoulder

What does the UV Index mean?

The UV index tells you how strong the sun’s UV rays will be; the higher the UV index, the greater the strength of the sun’s UV rays and the more likely you will burn.

The Met Office forecast uses the UV index to warn you of an increased risk to health from UK radiation. The ‘Solar UV Index’ was developed by the World Health Organization. The Met Office UV forecasts include the effects of:

  • the position of the sun in the sky
  • forecast cloud cover
  • ozone amounts in the stratosphere

You can find out more about the Met Office system here.

What does SPF mean?

SPF or Sun Protection Factor is worked out under lab conditions to give an indication of how much protection a sun cream can offer.

The following equation is used:

Minutes to burn without sunscreen x SPF number = maximum sun exposure time

So if you would burn without sun protection in 10 minutes and you applied a factor 30 protection, you could theoretically be protected for up to 300 minutes.

BUT, it’s important to remember that lots of factors can affect how long your sun cream will protect you for. Sweating, swimming, clothes rubbing on your skin, your skin type and strength of the sun will all reduce your protection.

It’s also important to remember that lab tests are different to real world use; most users won’t apply sun cream as liberally or regularly as scientist will for these tests.

What’s the difference between SPF 30 and SPF 50?

Interestingly, SPF50 offers only marginally better protection from UV radiation than SPF30 filtering out 98 per cent of UV radiation compared to 96.7 per cent blocked by SPF30.

Using SPF50 is not a substitute for applying suncream less frequently.  SPF50 sunscreen still needs to be applied as liberally, re-applied every two hours (or after swimming, exercising and towel drying) and used in combination with other sun protection measures including sun protective hats, protective clothing, sunglasses and shade.


What does broad spectrum mean?

Broad spectrum sun cream protects you from both harmful UVA and UVB rays. This helps protect you against sunburn, premature aging and skin cancer, including melanoma.

In the UK, there should be a SPF and also a star rating from 1 to 5 – the higher the number of stars, the more balanced your protection will be. It is recommended that you use a 4 or 5-star protection and SPF 30 or above.

Applying sun cream

What’s the difference between a non-organic and organic sunscreen?

A chemical or non-organic sunscreen contains active ingredients that protect your skin by absorbing the sun’s rays and causing it to undergo a chemical reaction that prevents it from damaging your skin. Most sun creams are chemical and you can check the active ingredients listed on the bottle. Physical sunscreens are usually hypoallergenic and may be a safer choice for people with sensitive skin. Physical or organic sun screens protect your skin by deflecting the sun’s rays. These contain ingredients such as zinc oxide or titanium dioxide.

Applying sun cream to an arm

What is the best sun cream?

Our sun safety ambassador, Jaime Nobbs, says the best sun cream is the one you will actually use!
You might have a preference based on the smell, texture, ingredients or price, it doesn’t matter as long as you apply the correct amount of broad spectrum SPF 30+ every two hours.

See our video ‘Staying Safe in the Sun’ below for more information.

Can I use suncream on a tanning bed?

In the same way sun cream protects you from harmful UVA and UVB rays omitted by the sun, it would also protect you from some of the harmful UV rays emitted by a sunbed. For this reason, sunbed users don’t wear sun cream, as it would prevent tanning. This contributes to making sunbeds a major cause of melanoma and we strongly advise against their use.

Melanoma Focus advises against the use of sunbeds by the general public. Find out more about sunbeds and melanoma.

Sun cream for babies and children

Protecting children from the sun helps prevent melanoma later in life. Ideally, babies and young children should stay in the shade, and wear loose, cool clothing when it is hot.

Babies under 6 months:

Newborn babies have very delicate skin and the NHS recommends they should be kept out of direct sunlight until they are at least 6 months old.

Babies over 6 months and children:

You can buy sun creams specifically made for children. These tend to be higher factor and fragrance free, to avoid irritating their delicate skin. You can also find sun creams designed to make application on wriggly children a little easier, such as roll-ons, sprays and brightly coloured lotions to make it easier to see if you’ve missed a spot.

Tips for applying sunscreen

  • Apply sunscreen liberally to exposed sites 15 to 30 minutes before going out into the sun.
  • Don’t rub the sunscreen into your skin but spread the sunscreen as uniformly as possible over the surface of the skin and allow to dry.
  • Re-apply every 2 hours or after an activity that could remove sun cream, such as swimming or excessive sweating

Remember! sun cream is just one sun safety tool. We also recommend:

  • Avoid the midday sun (between 11am to 3pm)
  • Wear a wide-brimmed hat and protect the skin with clothing
  • Protect your eyes with UV protected sunglasses

Watch Jaime’s video ‘Staying safe in the sun’