How to choose and use sunscreen

Sunscreen is used to help protect your skin from the sun’s damaging ultraviolet (UV) light when outdoors. It is important to choose the right sunscreen and know how to apply it correctly.

You should not rely on sunscreen as your only form of sun protection. Over-exposure to UV radiation is the main cause of skin cancer, including melanoma.

Tips for sunscreen use

  1. Use a broad-spectrum SPF30+ sunscreen.
  2. Use the ‘two coat approach’ when applying sunscreen – apply your sunscreen 20 minutes before going outside and again when you’ve been outside for 10 to 20 minutes.
  3. Reapply sunscreen every 2 hours, even if the label says you can wait longer.
  4. Use a water-resistant sunscreen if in the water.
  5. Minimise time spent in the sun from 10am to 4pm during the daylight saving months – even when using sunscreen.
  6. No sunscreen will completely shield you from the effects of ultraviolet radiation – you must also use other forms of sun protection such as slipping on a shirt with long sleeves, slapping on a hat and wrapping on sunglasses. Read more about sun safety.

Note: sunburn can also occur in the shade. This is because UV radiation is scattered in the atmosphere and is also reflected by surfaces such as concrete, water and sand.

How to choose sunscreen

As general guidance, the Cancer Society of NZ recommends the use of broad-spectrum, SPF30+ sunscreen.

  • Broad-spectrum sunscreen reduces the intensity of both UVA and UVB rays.
  • No sunscreen provides 100% protection from UV radiation.
  • If you have fair skin that burns easily you should choose an SPF 50+ broad-spectrum sunscreen.

Selecting a sunscreen depends on how sensitive your skin is to burning and to cosmetics, how dry or oily your skin is, previous sun and skin cancer history, and your general medical history.

  • If you have sensitive skin that has trouble tolerating sunscreens or cosmetics, look for hypoallergenic/low irritant sunscreens.
  • You may like to try a variety of sunscreen samples before deciding what you will use regularly.
  • If you are still having rashes you might have a sunscreen allergy and need to undergo allergy patch testing to identify a particular ingredient in sunscreens that is causing the problem.
  • If your skin is dry you would benefit from a sunscreen in a moisturising cream or ointment.
  • If you have oily skin or readily develop acne, choose a sunscreen in a lighter base, such as an alcohol-based lotion, spray or gel.
  • Lighter sunscreens are also better in hairy skin areas.
  • Special sunscreen sticks are suitable for nose, lips and around the eyes.

Read more about how to choose and use a sunscreen.

How to apply sunscreen

When applying sunscreen, use the ‘two coat approach’ – apply your sunscreen 20 minutes before going outside and again when you’ve been outside for 10 to 20 minutes. Applying two ‘coats’ of sunscreen:

  • helps cover up areas you may have missed on your first application
  • gives you a thicker, more protective, layer of sunscreen.

Reapply sunscreen every 2 hours.

  • Reapply your sunscreen every 2 hours, as well as after swimming or sweating.
  • Even if your sunscreen says it’s water resistant and will give you 4 hours of protection, reapply every 2 hours.

Remember: try to minimise time spent in the sun from 10am to 4pm during the daylight saving months – even when using sunscreen. Sunscreen is used to decrease your exposure to UV radiation when you can’t avoid being in the sun, not to increase the amount of time you spend in the sun.

How much sunscreen to apply?

Adults

An average sized adult needs about 7 teaspoons (35 ml) of sunscreen for one full body application.

  • Apply 1 teaspoon each to your face, your ears and your neck.
  • Apply 1 teaspoon to each leg, each arm, the front of your body and the back of your body.
Image credit: Cancer Council NSW, Australia


Children

Cover exposed parts of your child's skin with sunscreen (even on cloudy or overcast days). Don't forget to apply it to their shoulders, nose, ears, cheeks, and the tops of their feet. Reapply every two hours or more often if your child is active (sweating, towelling off, skin making physical contact with anything that might rub it off), even if the bottle claims 4-hour water resistance. Be especially careful to protect your child's shoulders and the back of their neck when they're playing, as these are the most common areas for sunburn.

Babies and toddlers

Babies' skin is very fragile so try to keep them out of direct sunlight as much as possible. This is especially important between 10 am and 4 pm from September to April. Be cautious about using sunscreen on babies under one year of age. It’s best to keep your baby out of strong sunlight.

  • But, if there is a risk that your baby might be sunburned, apply an SPF30+ broad-spectrum sunscreen on areas of the skin not able to be covered by clothing. If toddlers have to be in the sun, use recommended sunscreen on uncovered skin.
  • Sunscreen should be applied 15 minutes before going outside and reapplied every two hours.
  • Make sure that sunscreen is water resistant if your baby is playing in water.
  • If using sunscreen on a baby or toddler’s skin test it on a small area of their skin first and leave for 24 hours to check for a reaction. Stop use immediately if there is a reaction.

It is also important to provide full shade for the infant’s pram, stroller or play area. The material used should cast a dark shadow. The infant will still need to be protected from scattered and reflected UV radiation. Read more about sun protection for babies and toddlers.

Store your sunscreen properly and check the expiry

Store your sunscreen according to the label's instructions. This is usually in a cool place. Sunscreen that has been left out in the sun or near other sources of heat may not work. As a guide, do not store your sunscreen: 

  • in direct sunlight, such as on a window ledge
  • where it can warm up quickly, such as in the glove box in your car.

Most sunscreens last about 2 or 3 years when stored at the recommended conditions, as described on the label. Check the expiry on the bottle and discard if its past the expiry date. Also, discard sunscreen that has any obvious changes in colour or consistency. If sunscreen is left in excessive heat (eg. in the sun, or glovebox of a hot car), over time the sunscreen may deteriorate faster and may not give as much protection.

Learn more

Sun protection for babies and toddlers Cancer Society of New Zealand
Sunscreen Sunsmart Schools, The Cancer Society of NZ
Using sunscreen Health Promotion Agency and Sunsmart
How to choose and use sunscreens DermNet NZ

References

  1. Literature review on the safety of titanium dioxide and zinc oxide nanoparticles in sunscreens. The Australian Therapeutic Goods Administration. Version 1.0, August 2013
  2. Dermal absorption of nanomaterials. Danish Environmental Protection Agency, 2013
Credits: Editorial team. Last reviewed: 26 Nov 2018