8th July, 20205 min read

Sunscreen: How to apply it and how often

Medical reviewer:
Healthily's medical team
Healthily's medical team
Georgina Newman
Georgina Newman
Last reviewed: 09/07/2020
Medically reviewed

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Sunshine, in small doses, is good for your skin, but if you stay outside for too long, or when the sun is at its strongest, this can lead to sunburn. Sunburn is your skin’s reaction to too much ultraviolet (UV) radiation from the sun.

Sunburn can cause skin damage, early ageing and skin cancer, and it can happen to anyone -- you don’t need to have pale or freckle-prone skin to experience sun-related skin problems.

This makes sunscreen, along with other sun protection measures, important in protecting your skin.

Sunscreens work by either absorbing the sun’s UV rays (‘chemical’ sunscreens) or by blocking them so they can’t penetrate your skin (sometimes known as ‘physical’ sunscreens or sunblocks).

It’s important to know what type of sunscreen to use, and how and when to apply it.

What type of sunscreen should I use and how much do I need?

There are 2 types of UV radiation from the sun that are harmful to your skin (UVA and UVB), and dermatologists generally recommend using a sunscreen that offers protection against both (broad spectrum).

These recommendations are the same for all skin tones. You may need to take more precautions, however, if you’re pale or have lighter skin, burn easily, have a lot of moles or have a family member who’s been diagnosed with skin cancer.

Studies reveal that most people don’t use enough sunscreen to get the protection they need.

For adults, the British Association of Dermatologists (BAD) recommends using a minimum of 6 tablespoons (around 36g) per application to cover your body completely.

If you don’t use enough sunscreen, your skin may not get enough protection, so always use more than you think you need.

Young woman with sunburned shoulder on the beach

How often should you apply sunscreen?

Try to get into the habit of applying sunscreen before you get dressed at the start of the day so you can cover everywhere on your body easily. This also means that if your clothing slips or moves during the day, the parts of your skin that aren’t generally exposed will still be protected.

Remember to apply to the ears, neck, tops and bottoms of your feet and face. You should also apply sunscreen to areas of skin that might not normally be exposed to the sun, such as under the chin and arms.

For your face, you may like to use a sunscreen that’s designed specifically for the face, especially if you’re prone to spots (acne) or have a skin condition like rosacea. Oil-based sunscreens can cause problems with spots.

You should apply sunscreen 15 to 30 minutes before you go outside so it has time to soak in, then reapply at 2-hour intervals throughout the day. This is because sweating, being in water or actions such as drying yourself with a towel or removing clothing can rub off sunscreen.

The sun can even wear your sunscreen off over time.

If you’re going to be working or exercising outside, you should also apply sunscreen just before you go out.

Woman floating in the sea on sunny day

How often should you reapply if you’re swimming or sweating?

You should reapply sunscreen just after you’ve been swimming, as the water will wash it off. The same is true if you’ve been sweating, so you may need to apply more than every 2 hours.

It’s advised that you wear water-resistant sunscreen, but it’s especially important if you’re swimming, doing water sports or exercise that makes you sweat a lot. Water-resistant sunscreens may still protect your skin for up to 40 minutes after you come out of the water.

You should also take extra care if you’re in or around water, sand or snow as they can reflect the sun’s rays back onto you, increasing your risk of sunburn or skin damage. According to BAD, when the sun’s rays are reflected off snow this can increase radiation strength by up to 85% -- for sand it’s an increase of up to 17%, and 5% for water.

Sunglasses and sun hat on a beach mat

Does sunscreen expire?

Sunscreens do have an expiry date. Most will last for up to 3 years, and the US Food and Drug Administration says that even if a sunscreen product doesn’t have an expiry date it shouldn’t be used 3 years after purchase.

If you’re not sure, check the packaging to find a use-by date, or stick a label on the bottle with the date of purchase. If you’re using enough sunscreen, you should get through it fairly quickly.

Look beyond sunscreen for protection from the sun

It’s important to remember that sunscreen alone may not always be enough to protect your skin from the sun - especially when UV levels are high in the hotter months.

If you’re outside -- whether it’s hot and sunny or not -- try to:

  • keep in the shade
  • wear a hat (the top of your head can catch the sun too)
  • wear loose-fitting clothing that covers your skin
  • wear sunglasses that protect you from UV rays (the sun can even burn your eyes)

If you do ever experience sunburn, it’s important to act quickly to minimise any damage to your skin.

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