When I first moved to South Korea, I noticed a difference in how sunscreen was listed on products.
In Canada I was accustomed to only seeing “SPF” listed (example, SPF 30) and an indication that the product was “broad spectrum”. In South Korea, I was surprised to see two different ratings, the usual SPF rating, as well as a “PA ++++” rating.
If you are already familiar with the PA rating system, then this post will likely be unhelpful. But, if this is something new to you, read on to learn more about this UV protection rating.
A brief review of UV rays.
Let’s take a moment to quickly review some quick facts about ultraviolet (UV) rays.
When it comes to sun protection, we typically hear about UVB and UVA rays.
- UVB rays predominantly cause damage to the epidermal layer of skin (top)
- These rays are responsible for things like reddening/sunburns
- They are worse between the hours of 10 AM and 4 PM
- They do not significantly penetrate glass (windows, for example)
- UVA rays penetrate deeper than UVB rays (dermis)
- UVA rays play a major role in skin aging (wrinkles, sagging, etc.)
- These are the rays that cause tanning of the skin
- They can penetrate clouds and glass. So you are not more protected on a cloudy day or while inside your car, for example.
Both UVB and UVA rays play a role in causing skin cancer. Previously, it was thought that UVA were not as harmful as UVB, but new research in the past few decades has proven otherwise.
What’s is SPF?
Sun Protection Factor (SPF) is a measurement found on sunscreen products, and likely the one we are most familiar with.
SPF measures how fast it takes skin to redden under normal conditions (sun exposure, no sunscreen). So, and SPF of 15 means your skin will be protected 15X longer than if you weren’t wearing sunscreen at all.
However, beyond SPF 30 the protection increases are minimal. The difference between SPF 15 and 30 is fairly significant, where the difference between SPF 30 and SPF 50 is much less significant.
SPF 15 blocks 93% of UVB rays
SPF 30 blocks 97% OF UVB rays
SPF 50 blocks 98% of UVB rays
Most (and me!) suggest using products with a minimum of SPF 30.
It is very important to note that SPF is only measuring protection against UVB rays, not UVA.
So what’s this PA + system?
If you are thinking about purchasing (or are already a die-hard fan) any Korean or Japanese sunscreens, you will probably notice they have a PA rating as well as the usual SPF rating.
PA stands for “Protection Grade of UVA”.
The PA grading system was developed in Japan as a way to measure a sunscreen’s ability to protect against harmful UVA rays,
The PA system is based upon a Persistent Pigment Darkening (PPD) test. Similar to the SPF test mentioned above, the PPD test exposes unprotected skin to UVA rays and measure how long it takes the skin to tan. It then measures how long your skin will be protected, based on the ‘+’ rating the product is given.
There are currently 4 different PA ratings, though some countries are still only recognizing 3. Sunscreens in Japan and Korea will recognize the 4 ratings.
PA + factor between 2 and 4
PA ++ factor between 4 and 8
PA +++ factor more than 8
(new rating, not recognized yet in all countries using the PA system)
PA ++++ a factor of 16 and above
You might notice that it can sometimes be tricky to see exactly how much protection you are getting, since the ratings can vary quite a bit.
A PA+ and PA++ might both have a factor around 4 on two different products, a PA +++ might have a factor of 8, or it might have a factor of 15. There’s unfortunately no way of telling exactly how much protection from UVA rays you are getting.
Personally, I would stick to sunscreens labelled with either a PA +++ or PA +++ rating. I wouldn’t waste time on the smaller numbers as a PA of +++ will at least give you a factor of 8, minimum.
Hopefully this has given you a little insight into PA ratings on sunscreen. Sun protection can be extremely complicated, one could easily write a book with all the different information out there!
Keep it simple. Remember these two things if you are planning to purchase some sunscreen that uses a PA rating:
1. Choose a product with a minimum SPF rating of 30
2. Choose a product with a minimum PA rating of +++
If you follow those two tips you should be adequately protected against both UVB and UVA rays. As always, remember to protect yourself in other ways too, wear a hat, stay in the shade, and just be conscious of your sun exposure.
Most importantly, don’t forget to get out there and live your life!