I’m a dermatologist – here’s why you must NEVER use spray-on sun cream even if it is easier
WHEN it comes to spending time in the sun, spraying on some sunscreen is obviously better than nothing.
But while it's convenient, dermatologists still doubt whether it's the best choice of protection.
Dr Cristina Psomadakis, an NHS consultant dermatologist based in London, said she was all for 'practical advice' and if buying spray-on sun cream meant someone would be more likely to apply protection, then she supported it.
But she maintained her concerns about the products, noting it can be hard to know how much sunscreen you're actually putting on.
Dr Psomadakis told : "All sunscreens, including sprays, have to undergo testing to validate the amount of sun protection that they give in order to get the SPF rating.
"The issue with sprays is people often don’t know if they’re using the required amount in order to achieve the SPF rating on the bottle, because you don’t have a good perception of the quantity that’s being used."
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SPF - or sun protection factor - indicates how well a product protects against sunburn, and the number that follows tells you how long it would take for the sun's UV radiation to burn the skin when using the product exactly as directed, compared to not wearing it at all.
For example, it's estimated that if you usually begin to burn after ten minutes in the sun, a lotion with SP15 will protect you for 15 times longer than that, meaning up to 150 minutes.
This protection only lasts if you reapply your sun cream every two hours and you're getting a thick, even layer on.
This requires you apply two milligrams of sunscreen per square centimetre of exposed skin.
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Dr Hiba Injibar told The Sun you can follow the 'two finger rule' to achieve this: "For one area of the body i.e., your neck, apply enough sunscreen to cover two fingers on the area being protected."
It can be hard to know if you're slapping on the required amount of sun cream when it's spray form - and there's research to prove this.
A study conducted by the University of Colorado in 2019 found that when people applied a spray SPF to their forearms, most people applied only around 60 per cent of the amount needed to get the protection printed on the bottle.
It's also very possible you're wasting precious product when you spray it onto your skin rather than rubbing it in.
In fact, a study by Griffith University in Australia in 2021 found that you could be wasting as much as 93 per cent of your sun protection if you apply a spray in windy conditions.
On top of that, spraying sun cream into your hand probably still won't afford you the protection you need, because the cream will actually be diluted with propellant to get it out of the bottle.
Typically propellant will make up about half of the liquid that you get out, so you’ll need to use twice as much product as you think.
Dermatologists have previously shared three cheap sun cream swaps that are just as good as expensive brands.