It’s almost common knowledge that applying sunscreen is a must before going out of the house and especially when you’re at the beach. But have you ever stopped to wonder how these creams actually work and which ones should you use? Here’s a quick explanation.
As we all know, we get sunburned by the UV rays from the sun. Sunscreen then works two ways: by reflecting or scattering back the UV rays, or absorbing them and then releasing them as heat. And this is all the work of organic ingredients such as oxybenzone, and inorganic ingredients such as zinc oxide and titanium oxide. These ingredients are present in smaller particles that you won’t really notice them when you spread the sunblock on.
Most sunscreen can only block against one kind of UV rays, called UVB, which commonly cause sunburn. To also block against UVA rays—again another kind of UV rays—you should consider getting a broad-spectrum sunblock. In reality, there is no one sunblock or sunscreen that can guard against 100% of UV rays.
This then leads us to the SPF ratings found on sunblock. SPF, or sun protection factor, only pertains to the UVB rating. As you may already know, the higher the number, the better the protection. And the number itself refers to the amount of time that your skin needs to take before it becomes red.
So SPF 15 blocks against 93% of UVB rays and can protect your skin from burning for 15 times the amount of time before your skin gets sunburned. Meanwhile, SPF 30 sunblock can only block against 97% of these rays, and it will defend your skin for 30 times longer than usual. However, it ends at that, as SPF 50 is not proven as more effective than SPF 30. And unfortunately, there are no ratings for UVA rays.
Hence, it’s important to reapply sunscreen regularly when you’re outdoors.