The Concerning Reason Why Experts Don’t Like This SPF

Photographed by Poppy Thorpe.
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Gone are the days when sunscreen was an afterthought on a scorching day, something you'd pick up from the airport pre-holiday. In 2022, we're more serious than ever about sun protection.
And rightly so. According to Cancer Research, 86% of melanoma skin cancer cases are caused by overexposure to ultraviolet radiation (radiation emitted by the sun) and 86% of cases are preventable. Using sunscreen regularly is reported to reduce the risk of squamous cell carcinoma (a type of skin cancer) by around 40%.
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It's no wonder, then, that sunscreen is big business. The type of sunscreen you opt for — a spray bottle, a solid stick or a lotion — is largely down to personal preference. But ahead of a warm summer, cosmetic chemists and dermatologists are making their concerns known regarding a handful of very popular versions.
First up: aerosol spray sunscreen.

Is aerosol spray sunscreen any good?

Australian cosmetic chemist Michelle Wong went Instagram-viral recently for her take on aerosol spray sunscreens — the ones where you hold down the button and the SPF comes out as a continuous mist. "The problem with these is that they contain lots of 'propellants', which are liquidised gases," said Michelle. Most aerosol sunscreens contain these gases, which push the product out and are often referred to as propane, butane, isobutane or hydrocarbon on the label. But Michelle cites a recent Australian study which found that a standard aerosol sunscreen can be around one third to 60% propellant. In other words, you're actually getting about a third less SPF than the bottle says, as Michelle explains that SPF tests are done on the sunscreen without the propellant.
Pointing to a full-size bottle of aerosol SPF on her screen, Michelle adds that some of the propellant also lands as liquid on the skin so it's very hard to tell how much actual sunscreen you've applied. Put simply, you might not be using enough sunscreen at all — and this can be really dangerous in the sun.
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The comments under Michelle's post prove that lots of people have faced issues when using aerosol sunscreen in the past, such as very painful burns. Dermatologists agree that they might not be giving the best protection. "[Aerosol spray SPF] is definitely not as good as creams because coverage is very hit and miss," explains Dr Walayat Hussain, consultant dermatologist. Dr Hussain says a lot of this depends on how far you hold the spray from your skin and how long you spray over a particular area. But because the liquid gases feel like sunscreen, the amount of sunscreen you're getting can be quite misleading.
Whether you apply the sunscreen inside or outside is also a matter of concern. "Apart from the issues with the amount applied, wind is a problem," Michelle tells R29. "There's actually another study on spray sunscreens and wind which found that you lose 32-79% of the sprayed sunscreen in 10kph wind, and 28-93% for 20kph wind. These are considered light and moderate wind conditions." In other words, most of it might miss your skin entirely if the weather conditions aren't right.

Is there any benefit to aerosol spray sunscreen?

Aerosol spray sunscreens tend to be much lighter and dry down quicker so makeup wearers and those reapplying regularly tend to favour them over creams, which need rubbing in. In Dr Hussain's professional opinion, aerosol spray sunscreens are better than nothing. "Also, some people don't like the feeling of creams on their hands, which makes them greasy when they're at work, for example. So by using a spray they can avoid this issue."
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Michelle seconds Dr Hussain's thoughts on application. "If you apply enough sunscreen, sprays should be fine. It's just that it's harder to judge if you're applying enough with an aerosol spray." Michelle would recommend a pump spray instead and suggests measuring out how many sprays you need. "You can spray into a quarter teaspoon measure," she advises, and recommends being extremely careful not to inhale the sunscreen.
If you're looking for a spray sunscreen, rather than an aerosol, R29 rates La Roche-Posay Anthelios Invisible Sun Protection Spray SPF 50+, which is a lightweight cream that absorbs easily, or the Naked Sundays SPF50+ Hydrating Glow Mist, which is designed as a top-up spray. If you're on a budget, the Nivea Sun Protect & Moisture Spray Sunscreen SPF50+ is also a good option.

Is powder sunscreen any good?

Aerosol sprays aren't the only sunscreens to come under scrutiny this summer. Small enough to pop in a handbag and easy to use on the go (particularly if you're reapplying throughout the day), countless beauty brands are bringing powder sunscreen to market. But Michelle and Dr Hussain aren't too keen.
"I think powder sunscreens are misleading," says Michelle. "The data on them shows that you would need to apply a lot of powder for sufficient protection." Another of her Instagram posts shows just how much SPF powder you would need to dust over a small portion of skin to protect it — and it's a lot. "Powder sunscreens aren't a good way to protect your skin from the sun," Michelle captioned the post. "I definitely wouldn't recommend powder as your primary sunscreen — and I don't think they work well even as a top-up."
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Skin experts in the comments section agreed. "I can't stand them. So misleading," said Dr Natasha Cook, an Australian cosmetic dermatologist, while London-based dermatologist Dr Zena Willsmore blasted powder SPF for being pricy.
In terms of application, Michelle tells R29 that one popular skincare brand recommends applying the powder for 60 seconds. "This isn't how most people use the product," she says, "and it also works out to be extremely expensive." Instead, Michelle would recommend either applying a lotion sunscreen carefully or using a spray for top-ups.
Dr Hussain seconds the dubious nature of powder SPF. "I definitely think the amount needed to actually gain the alleged SPF is very misleading," he says, but "this is also the case with suncreams...If someone is outside in the summer, we usually suggest top-up every two hours due to evaporation. But if you've been in water and towelled down afterwards, you should reapply then."

Do you need to reapply sunscreen throughout the day?

This depends on a few factors. "Top-ups are only really necessary if you're getting a lot of sun exposure and you're moving around a lot," Michelle explains. "If you're sitting in an office all day and you're only getting a bit of exposure during your commute, you'll probably still have sufficient protection from your morning application — assuming you applied enough the first time."
If it's winter and you're heading to work when it's dark and coming back home when the sun has gone in, reapplication isn't really necessary. It's all about how much sun you're getting, whether it's summer or winter. For example, you could be sitting outside on a cold winter's day when the sun is shining. In which case, it makes sense to top up your sunscreen.
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As for the right amount of sunscreen, half a teaspoon is usually recommended for your face and neck combined, and for each arm. Then one teaspoon on each leg, the front of your torso and the back of your torso.

Is there a difference between expensive and cheaper sunscreen?

​Powder and aerosol sunscreen tends to be a little pricier than those housed in squeezy tubes or spray bottles. This might be because the packaging is a little more advanced but according to Dr Hussain, there is no benefit in buying expensive suncreams. "They are not superior," he reveals. "What people need to look for is broad-spectrum (UVA and UVB coverage)."
What does that look like? Many labels carry a five-star UVA rating, which Dr Hussain rates. The higher the star rating, the better the protection. He also recommends an SPF of 50 and above. "It's important to find one you like the colour and the feel of," he explains, "because if you don't like it, you won't use it." He explains that with creams, you get a better idea of how much has been applied. "In my opinion, they are better than sprays."

What are some good sunscreens?

If you're invested in protecting your skin from the sun, which SPFs should you go for?
Michelle rates Bondi Sands Sunscreen Lotion SPF 50+ Fragrance Free, $12.99 — a firm favourite among beauty editors and aestheticians. "This is an Australian sunscreen," says Michelle, "which means it's formulated to pass Australia's strict standards." It's also water-resistant for four hours, which she says is great for outdoor activities. Another one of Michelle's favourites (also adored by R29) is Ultraviolette Supreme Screen Hydrating Facial Skinscreen SPF 50+, $49. "This is another Australian sunscreen with high protection that works really well as a makeup primer."
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