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SPF, UVA and UVB –

July 1, 2015

It’s summer in most of the world which is odd for me as I live in Australia and its mid winter here but even so we all need to talk about sunscreens.

wear sunscreen thong

I’ve seen a couple of major papers in ‘summer world’ running stories on how SPF relates to UVB only and how hard it is for the public to read and understand sunscreen labels.  I have been left wondering if there is some kind of conspiracy agenda behind these stories as they seem to be labouring the point and creating an issue (in my opinion).

I’ve written about this before here about the folly of thinking that UVA and UVB are two things that exist and can be measured and controlled in complete isolation from each other – B for burn, A for ageing – oh how neat for the marketing department and the people too busy to be bothered to think.

While it is true that if you remove UVB radiation from the solar spectrum (say in a sun bed situation) you get a tan without burning you also get more chance of getting DNA damage, skin cancer and leathery skin.  Stick just UVB on living creatures and the results are equally tragic.

UVA and UVB wavelengths have been assigned my people to help make sense of the energy levels of the sun.  They are man-made or SYNTHETIC (to use a term that has holistic buy-in) markers that help us break solar energy down into bite sized pieces so that we might understand it better.  However, doing this has its limits and makes the process of developing sunscreens far too academic.

Cosmetic Chemistry is an applied subject in as much as it doesn’t make sense until it is applied. We can make the idea moisturiser in terms of moisture, oil and nutrient balance but if it feels like glue and smells like fish nobody will use it.  If you make a sunscreen that has the laboratory perfect blend of UVA and UVB filters but it is in a base that doesn’t spread well across the skin it won’t work.  We need to consider the whole.

So what is with this obsession with telling people SPF is entirely about UVB?

While it is true that SPF is measured by observing a visible alteration of the skin (a reddening), and that reddening is caused by the skins reaction to UVB you would simply not be able to get a sunscreen that recorded an SPF of more than around 15 WITHOUT having UVA protection as the skin would react to the fact that the sunlight reaching it was unbalanced (not natural).  When you place a UVB only sunscreen on the skin and then go under the sun you are in fact changing the QUALITY of the sunlight that hits your skin by blocking out one half of the spectrum while leaving the other unchanged.  This is similar to what happens when we go under a sun bed although unlike a sun bed where you only ‘tan’ for a few minutes we would literally be cooking ourselves in sun bed like conditions for hours at a time, day after day if we were to use these types of product and we would notice that.

Reddening and then burning is a natural response to too much SUN and as sun is naturally provided to us in its broad spectrum (UVA and UVB) glory then don’t you think it would be fair to say that burning is a natural response to exposure to naturally balanced sunlight OR UVA and UVB?

Wear sunscreen

The stories that I’ve read over the last week or so (here’s one of them) have led me to the conclusion that people will be less likely to trust and then use sunscreens after reading these articles as they have added to the confusion about SPF.  That is pretty bad as while sunscreens are not perfect they do help to prevent people who have to be out in the sun from getting burned.  In my opinion the articles have focused hugely on labouring the point that “SPF ISN”T GIVING YOU THE FULL STORY” while failing to tell people ‘but don’t worry, because on a bottle of sunscreen if you see the words ‘BROAD SPECTRUM’ you can be confident that the product WILL protect you from UVA and UVB in a balanced and natural way.  Also I am confused as to why wording like ‘low, medium and high’ instead of SPF would be better?  SPF is calculated to tell you, the person applying the sunscreen how long you can expect the product to protect you for as long as you comply to use instructions.  An SPF 15 will allow you to stay out in the sun up to 15 times longer than if you had no cream on.  OK so you have to estimate how long it might take you to burn but most of us have an idea as to whether when nude we would burn in 5, 10, 20 or 40 minutes.  If you didn’t know you could always make a conservative guess and say ‘OK so if I burn in 5 minutes naked I’d burn in 75 mins with my SPF 15 on so I’ve got a maximum of 75 minutes sun time’.

Maybe people can’t do math any more?  Surely there could be an Ap developed for that?

What additional information would labelling a sunscreen ‘low, medium or high’ give us?

Maybe it is time that newspaper article writers stop and ask these questions and think through the consequences of their posts before coming out and adding to the confusion.

Wear sunscreen.

Amanda x



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