What’s in sunscreen and how does sunscreen work?

Sunscreen contains chemicals that absorb/and or reflect UV radiation away from the skin. It also contains preservatives, moisturisers and fragrances.

There are two types of chemicals in sunscreen:

  • chemical filters, which work by absorbing UV radiation before it can damage the skin
  • physical filters, which contain microscopic particles that sit on the surface of the skin and act as a physical barrier.

Don’t rely on sunscreen as the first method of sun protection, as no sunscreen provides 100% protection. Always use other sun protection strategies, such as avoiding outdoor play during peak UV times and wearing hats and protective clothing. A sunscreen must be broad-spectrum and rated SPF30+ to give good protection.

What does ‘broad spectrum’ and the SPF number mean?

SPF stands for sun protection factor. The higher the SPF number, the more protection the sunscreen provides. The maximum SPF in Australia is 30+.

Sunscreen labelled as ‘broad spectrum’ filter out some UVA radiation as well as UVB radiation. (UVA and UVB both contribute to sunburn, skin ageing, eye damage and skin cancer.)

Can I use sunscreen on my baby/Is sunscreen harmful to my children’s health?

There is no evidence that sunscreen harms babies, but it’s best to protect your baby with hats and clothing and keep them in the shade. You can apply sunscreen to small exposed areas of the baby’s skin that can’t be covered with clothing.

If you baby reacts to sunscreen, try another product or talk to your doctor.

How should I apply sunscreen?

Firstly, look at the label and follow the manufacturer’s instructions. Most people apply too little sunscreen, which means they get a lot less protection than they think. A rule of thumb is that children need about half a teaspoon for the face, neck and ears, and half a teaspoon for each arm and leg. The important thing is to ensure there is a film of sunscreen over exposed skin. Apply the sunscreen 20 minutes before going outside, to allow the sunscreen to bind to the skin, and reapply it every two hours.

Does sunscreen expire?

All sunscreen is labelled with an expiry date and storage instructions. Sunscreen won’t work as well if it has passed its use-by date, or has been stored incorrectly, such as in the car, or left outside. It’s best to store sunscreen out of the sun and at temperatures below 25 degrees C.

This information has been provided by the Cancer Council NSW.

For more information see Baby sun care or Baby Care.