SPF, PA+++, Broad Spectrum labels - what do they mean?

Sunscreen is an essential step in our daily skincare routine before stepping out of the house.

But.

What do we really know about "sunscreen"?

I always noticed how the labels on sunscreen bottles / make-up base products stating "SPF 30 PA+++" etc. And I feel secure buying product that are labelled with SPF & PA +++ labels cos basically, that means protection for UVA & UVB - that's enough information to make me feel secure.

THEN recently, I started spotting "new" labels that indicate

"SPF 30" and  "PA+++" and  "Broad Spectrum" all at once!

So, what do they really mean? (I try not to question too much as I am not an aspiring cosmetic scientist or anything like that, but couldn't help it!)

The best answer I got when I asked around was:

"It means it covers/protects you from a broad-er spectrum of light." or
"It protects you from UVA and UVB."

Frankly - I don't quite get it. Then why do they need to indicate "Broad Spectrum" if it was really just the same function as a PA+++ value?

Maybe I am too dense, but I think there MUST be a better explanation to what these labels mean.

Hence, my quest begun!

In short, this product featuring all 3 labels means it has UVA and UVB protection (possibly even some UVC protection, though UVC supposedly doesn't reach earth atmosphere)

"PA+++" being graded by Japanese system for Sun Protection, while "Broad Spectrum"being graded by the U.S FDA (U.S Food and Drug Administration).

In long - read on..

Because I was curious and have done a fair bit of research on the different labels, (which I thought is pretty interesting and enlightening!) I just wanted to summarize all the sources added together (in details) with a tad of "personal touch".

We all know that the Sun causes us sunburns and premature aging - hence, applying SPF is an important routine before stepping out of the house. And - that is about all we know. (At least that WAS all I knew before this!) 

UVA, B, C ; The Light Spectrum ; What are these?!

In order to understand these labels and how much of these stuff is necessary,  it is important to first know about the "light spectrum". 

I combined 2 images from 2 different sources and added in my own text in blue to explain.

Image Source1 . Image Source 2

The shorter the wavelength, the more powerful it is and the shorter distance it can travel.

Think X-ray VS Radio frequency - we all know X-ray is super powerful, but you must be in a close proximity for it to reach you, yet on the other end, radio frequency are non-harmful and can travel long-long-long distances!

Visible light - (as we can all recognize when we see one) is a rainbow spectrum of 7 different colors. That is called "visible light", it's not harmful, ending with violet light.

So right before that comes Ultra Violet Light aka UV ray - yes - your UVA, UVB, UVC rays that burns and age your skin.

Each of it's "detrimental" function.

UVA - Causes major skin aging & wrinkling; Penetrates more deeply into the skin than UVB; Penetrates clouds & glass. (There's even UVA I and UVA II, read more here)

UVB - Causes sunburn; Does not significantly penetrate glass.

UVC - Most harmful as it can cause blindness & cancer; Thank God it is blocked by the Ozone layer.

(That's why we need to care about the environment and prevent Ozone depletion!)

So, What is SPF?

- SPF = Sun Protection Factor = Protection from UVB (Sun burns) NOT UVA.

The SPF number determines 2 things:

(1) Estimated length of time before you get burn;

(2) How much UVB rays are being blocked.

I tabulated the below charts to make it easier for understanding. 

POINT (1) Estimated length of time, and this is really just an estimate!

POINT (2 )How much UVB rays are you really protected from?

 

References:

Source from Skin Cancer Website Part 1, Part 2, Part 3

Source from Coola Suncare
Source from Badger Balm Badger Balm

Source from American Academy of Dermatology

What about PA+ or ++ or +++?

- PA measures protection against UVA

(which is why SPF & PA are often paired together to protect against both UVA & B.)

- "PA" means The Protection Grade of UVA - which is a Japanese system of measuring Sun protection from UVA that is based on PPD (Persistent Pigment Darkening) reaction reading which measures the "persistent darkening" of skin under UVA radiation. 

e.g. A PPD rating 10 technically allows one to be under UVA exposure 10 times more than someone with none! So, PPD 2-4 means 2 to 4 times more exposure than someone with none, and so on...

- PA+ measures PPD 2-4 

- PA++ measures PPD 4-8 

- PA +++ measures PPD 8 and above

(up to 4+s now) being the highest level of protection

References:

Source from Wiki

Source from Badger Balm

What about the term "Broad Spectrum"?

- Term used - to mean it measures protection against a "broad spectrum" of UV rays (namely UVA & B)

- Since 2012, FDA (U.S Food & Drug Administration) has established a standard broad spectrum UV test which determines if  a product is allowed to be labelled as "Broad Spectrum". Only products that pass this test can carry this label.

- So "Broad Spectrum" means this product provides both UVA & B protection with a certain percentage of the product's total protection being against UVA.

References:

Source from FDA 

IN CONCLUSION!

Truth #1

Though, SPF does kinda measure the length of time before you get sun burned, it is not meant to determine the duration of exposure because, the "estimated amount of time" you take before you get burn is really just an estimate. 

You may get burn even before you notice it, so use the formula as "a rough guide" 

Truth #2

The increase in SPF number doesn't give you the same increase in its level of protection.
(i.e. Just because SPF 10 gives you 90% protection doesn't mean SPF 20 is going to give you 180% protection - it doesn't work that way.)

Truth #3
Wearing a coat of SPF of 10 first and then wearing a coat of foundation of SPF 20 does not mean you have coverage of SPF 30. Don't assume it works that way.

Truth #4

Don't think that you don't need to apply SPF just because you are staying indoors because UVA can well penetrate glass and reach you, even when you are indoors.

So, if you really want to be protected,  

1. Get an SPF with PA+(s) OR Broad Spectrum Labels (they both basically goes to imply the product has UVA protection) to ensure you have both UVA & B protection.

2. Reapply SPF every 2 hours (even if you are using SPF 50 - they do wear out, depending on your activities)

3. Apply your SPF properly with 2.2mg/cm² of skin (about 1/4 to 1/3 of a teaspoon for an adult face - you need to "cover" your face evenly to get "coverage" yo.)

4. Apply it and allow 30 mins before sun exposure

5. Be more shade-conscious especially between 10am - 4pm