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Context
Growing up, I seldom used sunscreen. I can only recall using it sometimes at the beach or the swimming pool. Since I rarely got sunburned, I used to think that I didn't need one. However, ever since I started my skincare journey, my sentiment has changed. Even when I was not exclusively researching sunscreen, its importance was mentioned numerous times. Needless to say, I was eventually convinced to include it in my routine and thought that it'd be helpful to share useful information about it.
Importance of Sunscreen
There are two types of rays that can affect our skin, UVA and UVB. UVA can penetrate deeper into the skin and cause premature aging, while UVB can damage the top layers of the skin by causing sunburns. In worst-case scenarios, one might even get skin cancer.
Labels
SPF is short for Sun Protection Factor and indicates how much protection one gets from UVB rays. There are two main points to it, the percentage of UVB rays a sunscreen blocks and for how long it can do this. If a sunscreen is labeled to be SPF 30, it would most likely provide 97% protection which would last for approximately 300 minutes. That doesn't mean using a sunscreen with a much higher SPF can potentially provide 100% protection. An SPF 50 sunscreen only provides 98%, meaning that there's not much difference between using the two in terms of percentage of protection. However, an SPF 50 sunscreen would protect for a longer duration of 500 minutes.
PA stands for Protection Grade of UVA and is a grading system to identify how much protection a sunscreen provides against UVA rays. Depending on the number of '+' symbols there are, the protection varies. Essentially, the greater the number, the higher the degree of protection. This doesn't necessarily mean having sunscreen with many plus symbols is a must, as someone staying indoors and away from the sun most of the time may not need that.
A Broad Spectrum sunscreen protects from both UVB and UVA rays. Most of the time, sunscreen will have an SPF label with either a Broad Spectrum label or a PA label. This mostly depends on where the sunscreen is manufactured. A sunscreen manufactured in the US or Europe would likely have a Broad Spectrum label, while one manufactured in Asia would have a PA label.
Types
There are mainly three types of sunscreens Physical, Chemical, and a combination of both. A Physical (also known as Mineral or Inorganic) sunscreen contains titanium dioxide and/or zinc oxide which can provide reliable protection from both UVA and UVB rays. It does so by physically blocking them immediately after application. However, the two ingredients mentioned earlier can cause the sunscreen to leave a white cast and have a thicker consistency.
Chemical sunscreens contain chemicals referred to as UV filters which absorb and dissipate UV light as heat. Regarding the extent of UV protection, this type of sunscreen normally provides more protection for UVB rays than UVA rays. Fret not, when opting for a chemical sunscreen, besides checking for the labels mentioned above, look at the ingredients list to see if it contains good UVA filters such as Avobenzone. As these sunscreens do not contain titanium dioxide and/or zinc oxide, they most likely will not leave a white cast. However, the chemicals it contains might not be the best to use on sensitive skin and can cause the eyes to sting.
A hybrid of these two types of sunscreens does exist. They contain a combination of titanium dioxide and/or zinc oxide and some chemical filters.
Application
Sunscreen should be applied as the final step to a daytime skincare routine, just before make-up. When it comes to how much sunscreen to apply, there are many general recommendations but essentially, the right amount is the amount one requires to cover all the parts of the intended surface. For example, for the face, depending on how big or small it is, the amount required to cover all parts would vary.
Something worth noting about chemical sunscreens is that they have to be applied 20 minutes before sun exposure for them to dry and form a protective layer on the skin.
However, it doesn't end at application. Sunscreens do need to be re-applied as sweat and the oils we produce can wash it away. While doing strenuous activities, especially under the sun, it should be re-applied every 2 hours. If time is mostly spent indoors, there's not really a specific frequency as it depends on whether there's a window nearby, the frequency of exposure to the sun, etc.
Final thoughts
This sums up the information about sunscreen I find essential in knowing. Hopefully, I've shared it in an easy-to-understand manner. I would like to point out that I am not a dermatologist or a doctor but am here to share my experiences and what I have learnt on my skincare journey. Feel free to share yours with me or let me know if I have misrepresented any information. I'm currently using the Missha All Around Safe Aqua Sun Gel SPF50+ /PA++++. If you're curious to know how's my experience so far and what are my thoughts on it, stay tuned for my next post!