When browsing for sunscreens, we will always see the term “SPF”– this term stands for “Sun Protection Factor.” There is a misconception that SPF is the relative measurement of the time that it will protect you from getting sunburn. However, according to the Food and Drug Administration, SPF is the capacity of sunscreen to protect you from UV exposure. Specifically, it is the relative measure of how much UV radiation would take to cause sunburn in a protected skin relative to the amount of UV radiation that would produce sunburn in unprotected skin.
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How does SPF work?
A sunscreen provides your skin with screen-like protection to filter how much ultraviolet light can enter it. It is like a fly-screen door where the air can get through but the flies can’t. The Sun Protection Factor or SPF is the indicator of how much ultraviolet radiation or solar energy can get through the screen. A higher level of SPF can result in lesser UV that can pass through your skin.
SPF 30 allows only 3.3% of the ultraviolet light to reach your skin, which means that it can filter more than 96% of the solar energy that may penetrate your skin. On the other hand, an SPF 50 filters 98% of the UV light and only lets the remaining 2% get through. Meanwhile, an SPF 100 only allows 1% of the solar energy through your skin and filter the other 99%. You might think that the differences in the filtration level are not a lot, but they are pretty modest differences in terms of protection.
The efficacy of SPF varies from one person to another. Several factors can affect how SPF works. These factors include skin type and color, amount of SPF applied, and the frequency of reapplication.
In terms of skin type and color, it will be helpful to keep in mind that people with fair skin are more likely to absorb more ultraviolet radiation than people with dark skin. The reason behind this is the presence of melanin, which is a type of pigment that gives us protection against harmful UV rays. The darker this skin, the more presence of melanin that gives more protection against ultraviolet radiation.
On the other hand, when it comes to the amount of sunscreen applied, it would be helpful to note that it affects the amount of solar radiation absorbed by the skin. More sunscreen means lesser ultraviolet light absorption. Lastly, the frequency of reapplication depends on what activity you will be doing. For example, if you will sweat a lot in your activity, then the sunscreen may be washed out and you have to reapply again to maintain the protection.
Why is using SPF good for you?
Aside from protecting you from getting sunburn, there are several other benefits that you may get from using a sunblock. One is that it can help you avoid getting skin cancer. In fact, according to studies, using SPF 15 can decrease the chance of developing squamous cell carcinoma by about 40% and can reduce the risk of melanoma by 50%.