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Inconvenient fact of the day: SPF does NOT just refer to UVB

November 21, 2012

Last week was a bit funny. It starting off with a rather uncouth announcement by L’Oreal (why not the TGA?) that Australia had seen the light, had agreed to SPF 50 sunscreens and guess what?  They ALREADYHAVETHEMANDYOUCANBUYTHEMHERENOWSODOIT.   I hate those subtle, subliminal press-releases that sneak in while your eyes are still blurry…….

Anyway, what followed (rather un-surprisingly) was wave after wave of mis-information by people who have clearly not understood either

a)     how a sunscreen works

  • or

b)    how sunscreens are tested.

That’s not surprising when you look at the prime mover in all this and see that even they got it wrong.  L’Oreal?  Really?  Oh my goodness did the sky just cave in?

I’m going to look at one thing at a time until it makes sense to me so please come along and join me on this magical adventure.

This is me on a rock at Byron Bay. I’m pondering stuff, thinking, working stuff out. Apparently that has gone out of fashion but hey, who cares I’m nearly 40 now so EVERYTHING I do is unfashionable LOL……….

 

L’Oreal Press Release Mistake number 1:  An increase in the SPF claim (SPF represents the UVB protection factor) from 30+ to 50+ (a 50+ claim represents a minimum SPF of 60).

So, SPF is just UVB is it?  I must say that this week has made me question what I know too so it was somewhat heartening (but mostly disturbing) to find out that even people at the so-called top get it wrong.

So what I did was find some time to think about it, measured it, discussed it with industry professionals and read up on what happens when you take the UVA out of the solar simulator and irradiate living things.  I just can’t work out why this boat of wrongness is still sailing, I can’t be the only one who knows how to do ‘research’…..

Light doesn’t come to us in pre-packaged UV block ready meal sachets neatly bound so that we can choose just the right amount of UVA, UVB and visible light to get by.  Thinking that it does is, in fact rather silly. It’s a bit like saying that there’s no point in reading Shakespere because you know the alphabet and ‘unless I’m very much mistaken’ Shakesphere (bar the numbers) is just a collection of those letters that I know and love repeated over and over.  OR (if you are musically motivated) it is like going through a Mozart score and playing notes at random with no regard for the tune.  The saying ‘no rhyme or reason’ is apt here.

Key Point:  The relationship matters.  Take something out of context, divorce it of an application and it loses something in its meaning. Sometimes it even becomes meaningless.

In a lab setting sunscreens are tested using a solar simulator. This machine isn’t a UVB machine, it is a sunlight simulator which re-produces sunlight in both the UVA and UVB region.  That means that every sunscreen that has been tested on humans will have been tested using both UVA and UVB light.  Yes we know that it is the UVB part of that mix that turn the skin red and yes we know that it is that response that we are looking for when we test but the important fact is that all of this happens in a UVA + UVB environment so the redness only makes sense in the context of the mix.  Try testing sunscreens on people using just a UVB lamp and the results would be quite different. In animal tests all kinds of problems manifest when you change the quality of light reaching the skin (ie – opt for UVB only) including increased rates of skin cancers.   This is because you have effectively taken an animal to a different planet – you have changed the quality of the light reaching their earth-evolved skin.  What we want to do in a sunscreen test lab is change the quantity on sunlight that reaches the skin while maintaining its quality.

So, if L’Oreal got this wrong in their communication piece then who else is fuelling this mis-informed fire?   I found the results quite shocking:

“With a hot Australian summer on the way, those venturing out into the sun will now be able to better protect themselves from harmful UVA radiation that is largely responsible for melanomas and skin cancer

News Ltd website by Sue Dunlevy – National Health Corespondent.  13th November 2012.

Oh dear, there goes one of our large news sites.

“The performance of a sunscreen is determined by its Sun Protection Factor which measures the degree of protection against UVB radiation, its broad spectrum performance is measured by the degree of protection from UVA radiation”  Terry Slevin, Cancer Councils Skin Cancer committee.

Oh no, not the Cancer Council.

The Hunter Melanoma Foundation fears that people will think this. “when the stronger sunscreens reduce burning from UVB rays, not necessarily sun damage from UVA rays”

and there goes the Melanoma Foundation.

I’m sure that there are more but you get the picture and what a picture it is! How on earth is the average girl or guy on the street to know what to think when it comes to this sort of thing and where should they go for information?

Australia was the first country to implement a test for Broad Spectrum testing – Broad spectrum is the term that we use for wavelengths covering the UVA and UVB region.  This test was implemented on the basis that sunlight wasn’t chopped up into UVA and UVB portions and that the relationship between the two was and remains important (although we seem to be in danger of forgetting that).  It was created on the premis that as our skin is naturally adapted to sunlight in proportion we should replicate this as closely as possible in the laboratory.  This arm of science is called Photobiology – the study of the relationship between sunlight and biological systems and while photobiologists  recognize no cut-off points in the spectrum – it’s continual and that matters, Physicists see things differently.  Their mathematical minds set an arbitrary cut-off point between UVA and UVB at 315  and while that has proved useful for the sunscreen and sun filter industry it would be wise to not lose sight of the bigger picture when developing and testing products for sun protection. There ain’t no cut-off!

My advice:  While you have to have some trust in order to maintain a sense of mental clarity and a solid state of mental health it is not ‘healthy’ to rely on or put trust in just one outlet and especially unhealthy to elevate anything or anyone to guru status. Getting things wrong is what we humans do best.   The vast majority of the information that I gather is available to the public with a bit of prodding, investment and intelligence and that, I feel is a good thing as you can always check and challenge it.

So, what does this all mean for you?

Understanding how a sunscreen works and is tested is the first in a list of important steps. Get this wrong and nothing makes sense.

The bottom line is that SPF 30 plus sunscreens being sold here in Australia will all offer some UVA protection whether they sport the ‘broad spectrum’ claim or not and this is because they were all tested using a lamp that beams out ‘solar simulation’ and not ‘UVB’ alone.  That is important.

However, the renewed emphasis on the UVA/ UVB ratio offered by this new law is a good thing as it is possible to create a sunscreen that alters the natural balance between UVA and UVB by being either very strong at filtering out UVA rays or strong only in UVB.   Unbalanced sunscreens are problematic as what they do let through is foreign to the skin.  However, it is not thought that Australia is currently swamped my unbalanced sunscreens as to reach an SPF of over 15 requires a reasonable degree of coverage across both wavelengths and many brands have been aware of this and have been testing their UVA/ UVB ratio long before this new law came into play.

Knowing a little more about how a sunscreen works and how it is tested is an important first step in getting the right sun protection strategy for you.

Next cab off the rank is that curly statement that “If SPF 30 filters 96.7% of the sun and SPF 50 only 1.3% more (98%) what is the point?  I’m looking forward to that one!

 

 

 

2 Comments leave one →
  1. November 27, 2012 1:51 am

    Would love to understand more about how SPF works and especially how much it really matters to go from SPF 30 to SPF 50.

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  1. SPF, UVA and UVB – Confused.com? | Realize Beauty

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