Everyone knows that applying sunscreen is a very important step during their skin care routine. But do you know what the labels on sunscreen really mean? What does “PA” mean? What do those plus signs mean? What does the number after “SPF” really mean? And what is the difference between “broad spectrum”, UVA, and UVB?
This post contains affiliate links. For more information, see my disclosures here.
First, let me explain the difference between inorganic and organic sunscreen:
Inorganic, is what is also known as “mineral” or “physical” sunscreen. It is the type of sunscreen that leaves a whitecast on your skin. Although many people are not a fan of this, inorganic sunscreen actually has maximum protection against UVA rays because it usually contains titanium oxide, zinc oxide, or a combination of both. It also protects from UVB rays by deflecting the rays away from skin. One of the benefits of inorganic sunscreen is that it is the best option for sensitive or redness-prone skin since the UV filters (i.e. titanium dioxide) is gentle and normally does not cause stinging.
Some examples of inorganic sunscreens are:
Organic, or “chemical” sunscreen, on the other hand has a light texture and does not leave a whitecast unlike inorganic sunscreen. Some UV filters that it may have includes oxybenzone, octorylene, avobenzone, PABA, Uvinul A, Tinosorb S/M, and many more. Although organic sunscreen has a lighter texture and usually doesn’t leave a whitecast, it tends to be more irritating than inorganic sunscreen, depending on what kind of UV filter is used. However, if you feel like you will not be able to stick with applying sunscreen due to a whitecast, then definitely experiment with organic sunscreens that work will with your skin. As long as you find something that encourages you to apply sunscreen on a daily basis, then that’s all that matters! Some examples of organic sunscreens are:
As an Amazon Associate, Petite and Soigne earns from qualifying purchases.Combination sunscreen also exists, and it is personally my favorite kind of sunscreen. These sunscreens use a combination of both inorganic and organic sunscreen, offering higher protection for a longer amount of time. Some examples of combination sunscreens are:
As an Amazon Associate, Petite and Soigne earns from qualifying purchases.The EltaMD is personally my favorite. It is oil free, safe for sensitive skin, and is the sunscreen that is currently being raved about within the dermatology community. I also use their lip balm with SPF in it, as well as the waterproof sunscreen by EltaMD. (This sounds like I am sponsored by the brand, however I am not! I genuinely love this brand!)
You can read more about the specific and scientific reasons why Elta MD is the sunscreen that I decided to stick with here.
“SPF” stands for Sun Protection Factor. SPF measures how long your skin can handle being exposed to the sun before it begins to burn (redness) compared to bare skin. It is the sunscreen’s ability to shield from the sun’s UV rays.
For example, if a bottle of sunscreen states that it is “SPF 15”, this means that it will help your skin handle being exposed to the sun 15 times longer before it becomes burned compared to bare skin. It generally takes around 10 – 20 minutes before your skin begins to burn without sunscreen, so in the case of SPF 15, it will help prevent your skin from burning 15 times longer than the 10 – 20 minutes. In other words, you skin will be protected for about 150 – 300 minutes, or 2.5 – 3 hours.
SPF generally protects you from UVB rays. (I will go into detail about UVB and UVA later in this post). In order to be protected from both UVA and UVB rays, you have to search for a product that states that it is “broad spectrum“. That’s it!
“PA” stands for Protection Grade of UV. PA measures how long your skin can handle being exposed to the sun before it begins to turn brown (PPD) compared to bare skin. PPD stands for persistent pigment darkening. PA is a Japanese method of measuring UVA protection factor which is being used internationally as a way to measure how protected you are from UVA rays. The PPD reaction reads at 2 – 4 hours of sun exposure, and it goes hand in hand with the plus signs “+”.
The “++” signs are what indicate how long a person will be protected from UVA rays.
If a product’s sunscreen is 2-4, then the PA will be: PA+
If a product’s sunscreen is 4-8, then the PA will be: PA++
If a product’s sunscreen is 8-16, then the PA will be: PA+++. This is currently the highest grade of UVA protection available, except in Japan where there are a few PA++++ (PPD of over 16) products available.
Broad Spectrum means that it provides protection from both UVA and UVB rays. However, many times products fail to effectively protect against UVA rays. This is because products that contain zinc oxide (inorganic/mineral/physical) are the ones that effectively protect against UVA rays. This is why it is important to use products that show the amount of SPF and PA so that you are aware of how well you will be protected.
UVA vs UVB rays. An easy way to remember the difference between the two types of rays is to look at the last letter:
UVB = Burning.
UVA = Aging.
Easy, right?
UVB rays, or short wave ultraviolet B rays are what burn your skin. It causes temporary effects such as the burning and hot sensation on your skin.
UVA rays, or long wave ultraviolet A, are the rays that cause permanent including aging and cancer.
Fun Fact! The sun also has UVC rays! However these kinds of rays do not pass through the Earth’s atmosphere, so we don’t have to worry about it 🙂
Many people believe that a product containing a higher SPF number is better than a product containing a lower SPF number. This is not necessarily the case.
This is because SPF 15 blocks about 94% of the sun’s rays.
SPF 30 blocks about 97% of rays.
SPF 45 blocks about 98% of rays.
There is really no need to go higher than SPF 45 since you are being protected from virtually all of the sun’s rays.
At the end of the day, consistent application is what’s important! Remember to reapply around every two hours, especially if you will be interacting with water!
Who: Everyone who is over 6 month of age! It should be the last step in your skin care routine! ** Makeup alone does not provide enough protection!**
What: Any kind of sunscreen that does not irritate your skin! Something that is over SPF 30, that has atleast a PA of “++”, and make sure you are using enough to cover your face, neck, and chest. Don’t forget your ears, lips, and any body part that is exposed!
When: Every day, Every morning, and reapply every 2 – 4 hours, especially if you are using a low SPF, will be doing any activities that involve sweating, or will be in water.
Where: Everywhere that is exposed! Common areas that people forget to apply are: the ears, lips, behind the neck and knees, and your feet!
I hope you found this post useful! What is your favorite kind of sunscreen and why? Have you ever had a bad sun burning experience? Let me know in the comments below!
Stay humble.
Ivy
This post contains affiliate links. For more information, see my disclosures here.
References:
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3543289/
- https://www.pinkparlour.asia/ph/stories/what-do-sunscreen-numbers-mean-does-spf-100-gives-double-the-coverage-of-spf-50/
- https://www.colorescience.com/learn/what-is-pa
http://cebp.aacrjournals.org/content/15/12/2546.full https://www.sciencedirect.com/science/article/pii/S0022202X1534166X https://www.sciencedirect.com/science/article/pii/S1098301511035303 https://www.sciencedirect.com/science/article/pii/S0190962210000228