Choosing the right sunscreen Part 1


What sunscreen should you choose?

If you look carefully at the labeling, you can see UVA, UVB, SPF50 +, PA ++++…


And regardless of the label, they all claim to block UV rays well …

A lot of plus signs look nice… The more pluses, the better, right? And if there’s a high SPF number with lots of +’s, this looks like the best one??

A lot of people may have some questions here (we had a lot, so decided to look into it a bit more ourselves).

It is correct that sunscreen with a higher SPF number and more plus signs (+) protects UV rays for a long time, but this may also cause more skin irritation and be the most harsh for your skin.

It would be ideal to choose a sunscreen that both protects and causes the least amount of stress on the skin depending on your skin or situation.

So we prepared a little cheat sheet for sunscreen for you.

What does SPF 50 PA+ mean?


What is the difference between UVA and UVB?

Both are types of UV light, but they affect your skin differently.

UVA: UV light that ages the skin and penetrates deep into the skin.

UVB: UV light that burns the top surface of the skin.

What does SPF 50 mean?

SPF stands for Sun Protection Factor (SPF), which is the ability of the sunscreen to block UVB.  The number represents the power or ability of the sunscreen to block UVB.  

It’s actually assigned using the following formula:

SPF = Percent of erythema after applying UV blocker divided by percent of erythema without applying UV blocker

* Erythema: redness of irritated skin

For example, if you put on sunscreen, and 1% of your skin experiences redness, and without the sunscreen, 50% of your skin experiences redness, then the SPF = 50.  1/SPF will tell you the percentage of UV rays that are not blocked.  For SPF 50, that is = 1/50 or 2% of UV rays are not fully blocked.

That means a sunscreen with SPF 50 offers 98% of UV protection!

In other words, the higher the SPF, the better it blocks UVB light.

What does PA +++ mean?

PA stands for Protection grade of UVA, which means the ability to block UVA light.  The plus signs (+) to the right of the PA are an index indicating the effectiveness of blocking UVA.

For this PA index, each plus corresponds to the length of time the sunscreen remains effective at blocking UVA.  For example, 

PA +: 2 times (2-4 hours) UV protection.

PA ++: 4 times UV blocking effect.

PA +++: 8 times UV protection effect.

PA ++++: 16 times UV protection.

In other words, the more +, the longer and more effective it blocks UVA.

And while blocking UVA is important for your skin’s health, you don’t want the prevention to be worse than the possible harm.  For sunscreens with high PA ++++, it is likely that the sunscreen has more irritating and possibly harmful ingredients to achieve such an effective UVA block. 

So to get a safe AND effective sunscreen, it’s okay to choose a lesser PA sunscreen and simply reapply it more frequently.  Even a PA+ can be used and reapplied every 2 hours or so.

So keeping all this in mind, here’s a little guide for how to effectively block UV rays while putting less pressure on your skin:

The Proper use of sunscreen.


SPF30 or higher for indoors.

SPF50 or higher for outdoors.


PA ++ for indoors.

PA +++ or higher for outdoors.


Reapply every 2 hours.


Rain or snow, apply anytime, even under water.


Apply a quarter-size amount to your face.

When at the beach, you should apply a shot glass size amount, but if it is too difficult, just reapply it frequently.


Double cleansing is essential to remove the sunscreen after use.

If the sunscreen is a chemical type, then make sure to use a cleansing oil to remove it.  If the sunscreen is a physical type, then a cleansing water is okay to use for removing.  More on this in Part II of this article.


And just a few more benefits of frequent sunscreen use:

Protects the skin that is prone to burns from the sun.

Prevents collagen destruction.

Prevents the skin from drying and becoming sensitive.

Thank you sunscreen!

Depending on your situation, you now may be able to decide which SPF PA sunscreen to choose.  

But there is one more thing to get right.

In the next post, we’ll talk more about choosing the right sunscreen in the 2nd part – Chemical type sunscreens vs. Physical type sunscreens!


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