January 10, 2021
Being the sunscreen Nazi I am (much like the soup nazi in the days of Seinfeld) I’ve made it my mission to dispel the myths, reset the truths and put the ‘fun’ back into the sun. It’s only been a few summers where SPF 50 has been made available in Australia (It’s been on the foreign market for years).
While it’s great to have choice, what the eff do the numbers even mean?
It’s assumed that the higher the number, the better the protection right?
Did you know that the level of UVB protection between and SPF 15 and an SPF 50 is only a difference of 5%!!!
An SPF 15 provides 93.3% protection from UVB rays while an SPF 50 gives you 98% UVB protection.
So the real question here is…. What do those numbers really mean???
Your skin has its very own unique burn time rating. Based on your skin colour, genetics and where abouts in this big wide world you’re getting your guns out, your skin will have a unique span of time before the sun gets too much for your skin and you begin to burn or tan (Yes! A tan is skin cells in trauma!)
So for me, being the glow in the dark, fair skinned, red head, I have about 4 minutes before my skin starts to burn. That’s not even enough time to skip across a hot car pack and onto the beach! (I could probably get sunburnt on a full moon!!!)
For the ease of maths, let’s say your skin’s natural unprotected burn time is 10 minutes. Thats 10 minutes of sun exposure before your cells begin to react to the over dose of UV radiation.
Wearing an SPF 15 rated sunscreen means that ideally, you should be able to stay out in the sun 15 times longer than your natural sunburn time before seeing signs of skin burning/redness, freckles darkening or tan developing.
So the higher the SPF, the longer your burn time. Wearing an SPF 50 means that your burn time would be 500 minutes
Of course it’s not an exact science, everybody’s skin is different, but it does give you a better idea of how often you need to reapply your sunscreen. (I dont advicate that ANYONE stay 500 minutes in the sun without a shaded break!)
|SPF RATING||% of UVB protection|
So if after 20 minutes of being at the beach you go in for a swim, some of your SPF has just been washed off, or compromised. So you need to reapply in order to give your skin continued sun protection. SAme goes for sunscreen being rubbed off on clothes or sweated off.
Depending on your activity, wearing an SPF 15 or an SPF 50 makes no difference as they have both washed off and you need to apply to protect again.
Knowing your unprotected burn time can help you calculate the correct SPF rating for your skin and the level of protection that you need. Burn time can vary greatly from person to person, even if you are in the same family. (My fair skinned, blonde sister gradually builds up a golden tan, whilst me being the freckly red head would simply burn, peel, then burn again.) Evident on our most recent holiday. We both got a mild burn on our feet, the next day hers was brown, mine was still red and sore 3 days later (Same parents, same genetics, completely different burn time and response) If in doubt, calculate it on 10 minutes.
Another thing you need to know is that SPF + SPF does not equal a higher rating.
So if you apply an SPF15 that is in your daily moisturiser and follow it with your make up that is rated at SPF 20 together, it does not equal a protection of SPF 35. You are only protected at the rating of the highest SPF. So you would have an SPF of 20.
I am always of the belief that a moisturiser and a sunscreen have two separate actions. A moisturiser is designed to penetrate into the skin to provide hydration and to prevent water from evaporating from the skin. Sunscreen is designed to sit on the skin’s surface and reflect or absorb UV radiation. So having the two in the same bottle means that one action has had to compromise so that the other action can be most effective. I would hope in this case, SPF protection trumps moisturising ability. Always keep your moisturiser and your sunscreen as two separate products.
Sunscreens work in two different ways. There are physical blocking ingredients; most commonly are zinc and titanium dioxide, and chemical blocking ingredients, like diethylamino hydroxybenzoyl hexyl benzoate (Its stage name is Uvinul A Plus yes that’s one ingredient and yes its’ a mouthful… but it’s protects you from UVA).
Physical blocking ingredients work to reflect the UV rays away from your skin to protect the internal workings of skin cells.
Chemical blocking ingredients absorb the UV rays into the skin and filter them out through your body’s waste disposal system.
There are arguments, good and bad for both types of blocking but a general broad spectrum sunscreen contains both physical and chemical ingredients.
Much like your mum told you to wait fifteen minutes after eating before dive bombing in the pool, same rule applies for sun screen. Ideally, you should apply before you leave home to allow the cream to settle into your skin. Otherwise, if you whip it out at the beach, you’ve already left your skin exposed and the minute you apply then take a dip in the water, it’s all left floating on the surface of the water and not on your skin. Give your skin the best defence and let the sunscreen adhere to your skin.
To re-apply at the beach, make sure you dry off then apply and let it settle before your next dunk in the waves.
How you store you sunscreen is really important too. DO NOT store your sunscreen in the glove box of your car or in the boot or anywhere else in your vehicle for that matter! (in fact, if you currently do this, go and get it right now. Throw it in the bin! I’ll wait til you get back….)
Being exposed to extreme temperature changes like the heat of your car in full sun, will cause the ingredients in your sunscreen to deteriorate, breaking down the active sun protection and risking your skin. Replace your sunscreen every year. It’s a small price to pay for safe skin!
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