“Many People Apply Less Than Half the Recommended Amount”: SPF Myths Debunked by a Scientist
There are a number of myths about sunscreen kicking around, especially in the world of health and wellness. And unfortunately, in this case, these myths can be extremely harmful if people choose not to wear sunscreen because of them.
In order to debunk some of these myths, we enlisted the help of Dr Michele Squire, a PhD-qualified scientist, former Registered Nurse, and founder of Qr8 and Qr8 MediSkin. Dr Squire has a wealth of knowledge about skin and skincare and is extremely passionate about sun safety.
In case you’re on the fence about sunscreen, you’re not sure how much to use or when you need to wear it, Dr Squire answers all of your questions and busts some myths below.
You only need sunscreen when you go to the beach or are outside for long periods of time.
“Most people wear sunscreen for outdoor activities but don’t recognise that repeated exposures to sunlight during everyday activities, whilst not enough to cause sunburn, result in cumulative damage to DNA,” said Dr Squire.
“This results in both skin cancers and aged skin — something called ‘photoaging’ (deep wrinkles, skin roughness, broken capillaries and hyperpigmentation). (P.S. ‘Indoors’ is a relative term — you will be exposed to UV if working near windows, driving the car, popping out to get a coffee, walking to and from the office etc.)
“So if the UV index is three or higher, and you are in the sun, you need sun protection (clothing, hat, sunglasses), and sunscreen on areas you can’t protect with these other methods. Period . Figuring out the UV index is simple — there are multiple weather sites and apps that will do this for you — I use the Cancer Council SeeUV app on my phone.”
Clean sunscreens are a thing.
“‘Clean’ is a term developed by marketing departments to sell a product, nothing more,” says Dr Squire. “There is no industry regulation of the term, so it can mean anything a company wants it to mean (and therefore means nothing). ‘Clean’ also does not mean effective, safe, sustainable, green, non-toxic, vegan, organic, chemical-free or natural.
“It’s simply a sales strategy based on fear-mongering or a charming story about how the ingredients were sourced. Marketers simply exploit consumer confusion about well-regulated, tested and safe synthetic cosmetic ingredients to sell products. This is especially true around specific sunscreen filters (the so-called ‘chemical’ filters). There is absolutely zero good-quality scientific evidence that sunscreen chemicals are harmful.
“So if choosing ‘clean’ sunscreen is your personal preference, then go for it. But don’t allow yourself to be ‘greenwashed’ into believing that ‘clean’ indicates safety or efficacy. Think critically about your purchasing decisions, and find an information source that explains all the facts.
“‘Clean’ or otherwise, the best sunscreen is one that is properly regulated (look for the AUSTL number on the product to indicate it has been tested and listed with our TGA), that you will wear (and wear enough of), and at a price you can afford.”
Those with dark skin don’t need to wear SPF.
“The melanin content in lighter skin tones provides a natural SPF of around 3.4 (see why we need sunscreen!), increasing to around SPF13 in black skin,” said Dr Squire. “So the darker your skin, the better your protection against ageing and sun cancers caused by the sun’s UV rays (the main reason JLo appears ageless — not olive oil) .
“But there’s a downside — more melanin predisposes darker skin to hyperpigmentation from breakouts, injury and irritation/inflammation. And melasma (hormonal pigmentation) is more common in these skin types. So it’s a myth that darker skin types don’t need to wear sunscreen or use sun protection. Everyone needs protection from the sun’s UV rays!”
If I wear SPF50+ I can stay in the sun longer than if I’m wearing SPF30+.
“This is the wrong way to think about sunscreen — it’s never your first line of defence against the sun! (ask anyone who has tried to use sunscreen to extend their time at the beach and ended up with a painful sunburn!).
“A better way to think about choosing SPF30 vs SPF50 is: whilst I’m in the sun and using other sun protection behaviours, SPF50 gives me a bit more protection than SPF30. This is because SPF30 sunscreens filter around 96.7 per cent of UV rays, vs 98 per cent for SPF50+ sunscreens .
I don’t need to wear sunscreen as my makeup products contain SPF.
“Because SPF testing is performed with a standardised amount of sunscreen (2mg/cm2), you need to apply it to your skin at the same thickness to get the SPF stated on the container,” says Dr Squire. “This equates to one-quarter of a teaspoon applied just to the face, and another half teaspoon for the neck (front and back) and chest (décolletage). And don’t forget the back of the neck, ears and part line in your hair.
“Scary fact: most people apply less than half the recommended amount of sunscreen!  This is why moisturisers and makeup with sunscreen aren’t primary sunscreens — it’s impossible to get this much of them onto your face! And why sticks and sprays are convenient for topping up sunscreen, but not a reliable way to ensure that you are getting a sufficient application in the first place. Unless you’re measuring out enough spray sunscreen to get a proper application first (we show you how here).
- Lin JY, Fisher DE. Melanocyte biology and skin pigmentation. Nature. 2007. PMID: 17314970.
- Neale R, Williams G, Green A. Application patterns among participants randomized to daily sunscreen use in a skin cancer prevention trial. Arch Dermatol. 2002. PMID: 12374537