How Does Sunscreen Work?
There are two main types of sunscreen: chemical sunscreens and physical sunscreens.
Physical sunscreens were the first type of sunscreen. These products sit on the surface of your skin, actively blocking UV rays. They can feel a little heavy on the skin but are perfect for all skin types, including sensitive skin.
Chemical sunscreens penetrate the skin and absorb harmful rays before they can damage the epidermis. These products are typically fast-absorbing, sheer, and lightweight. Unfortunately, chemical sunscreens may cause sensitivity and irritation. Discover more about the pros and cons of chemical and physical sunscreens in our handy guide, Chemical vs Physical Sunscreen: What's the Difference?.
Although your everyday makeup may contain SPF, it isn’t enough to offer full protection throughout the day. Find out more about wearing a separate sunscreen in No, Your Foundation Doesn't Have Enough Sun Protection.
What Is the UV Index?
The BOM UV Index is a measure of how high the ultraviolet radiation is on a specific day and is included in your local weather forecast. Remember, it’s not the heat that damages your skin but the UV rays. Sun protection measures are recommended when the UV Index is 3 and above, a common occurrence in the Australian climate. You can find out more about the UV Index on the Bureau of Meteorology’s website.
The UV Index and Sunscreen
Every sunscreen has an SPF, or sun protection factor. This is determined by how much time it takes for UVB rays to burn the skin, compared to skin that has no sunscreen. An SPF tells you how much time the product can be expected to work for. During periods when the UV Index is higher than 3, you should be wearing at least SPF 30 and re-applying it every 2 hours. However, we still recommend wearing sunscreen every day for maximum protection.
You can explore our favourite sunscreens to keep your skin protected in our guides The Top 6 Sunscreens for Oily Skin and The 7 Best Physical Sunscreen Brands For Sensitive and Acne-Prone Skin in 2019.
Once you’re armed with a new sunscreen, it’s important that you know how and when to apply it. Otherwise, you might not be providing as much skincare protection as you think. Follow our extensive sunscreen application guidelines to make sure you’re getting the most out of your sunscreen and keeping your skin fully shielded from harmful UV rays.
How Much Sunscreen Should I Use?
Not using enough sunscreen is a common mistake, especially when using physical sunscreens that can feel heavy on the skin. It’s recommended that you apply 2 milligrams of sunscreen per square centimetre of your skin. This works out at around 1/2 teaspoon for your face, 1 teaspoon per arm, 2 teaspoons for your torso, and 2 teaspoons for each leg.
Does Sunscreen Expire?
If you’ve raided your bathroom cabinets and found an old sunscreen, we seriously recommend you chuck it straight in the bin. You’re better off using nothing rather than an expired sunscreen! Expired sunscreen not only loses its effectiveness but also may introduce nasty bacteria and fungi to your skin.
Sunscreen can last for up to three years, but always check the bottle for an expiry date. Be sure to store your sunscreen in a cool cupboard, as storing it in a warm environment can cause it to expire more quickly.