Sun Protection

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SPF stands for ‘sun protection factor’ – the sunscreen’s ability to filter out ultraviolet B radiation (UVB).

The higher the SPF number, the greater the protection. SPF 15 will block 93% of UV radiation, while a SPF 30+ will give you more protection, screening out 96% of UV radiation. Find out which SPF you should use.


UVA protection in sunscreen guards against skin ageing by filtering out ultraviolet A radiation (UVA).

In NI we measure UVA protection with the ‘star’ system. Sunscreens can have anywhere from 0 to 5 stars.

Look for a star rating of 4 or more.

 Which sunscreen should I buy?

For maximum protection, choose a broad-spectrum sunscreen that filters out both UVA and UVB radiation and has:

  • SPF of at least 15
  • UVA star rating of 4 or more

Price is not an automatic indication of the quality of a sunscreen – the critical factor is that the sunscreen you purchase has an SPF of 15 or more and a UVA star rating of 4 or more.

Applying sunscreen

Apply your sunscreen generously at least 30 minutes before going outdoors. Most people apply too little resulting in 50-80% less protection than specified on the bottle.

Reapply every two hours or more frequently, especially if it is being rubbed off through swimming or exercise.

It’s important to remember that no sunscreen gives 100% protection against UV rays.

Shelf life

All sunscreens should show an expiry date and storage conditions. Most sunscreens can last for two to three years when stored correctly. Sunscreens vary in their ability to withstand heat and may deteriorate more quickly if kept, for example, in a hot car.

Sunscreen and babies

There is no evidence that sunscreen is harmful to babies. A baby’s skin is, however, very sensitive and it’s preferable to use clothing, hats and shade to prevent over-exposure to UV radiation. Babies under six months should be kept out of direct sunlight.

If exposure to sunlight is unavoidable, use only small amounts of sunscreen on unprotected areas. Always use a sunscreen which has been specially formulated for babies with a high SPF 25 or greater and UVA 4 or 5 star. If your child’s skin has an adverse reaction to the sunscreen, stop using immediately. Find out more about how to protect your children’s skin.

Once a day application – is once enough?

Some sunscreens claim to provide effective protection after just one application. But reapplying sunscreens regularly is very important because you are more likely to get even coverage and avoid missing bits.