Why Skin-Care Experts Don’t Recommend Spray-On SPF

Welcome to Sun Blocked, Refinery29’s global call-to-action to wake up to the serious dangers of tanning. No lectures or shaming, we promise. Instead, our goal is to arm you with the facts you need to protect your skin to the best of your ability, because there’s no such thing as safe sun.

Gone are the days when sunscreen on a scorching day is an afterthought, something you'd pick up before a beach trip. In 2023, we're more serious than ever about sun protection.

And rightly so. According to Cancer Research UK, 86% of melanoma skin cancer cases in the U.K. are preventable. Using sunscreen regularly is reported to reduce the risk of squamous cell carcinoma, a type of skin cancer, by around 40%. Unsurprisingly, sunscreen is big business. The global sunscreen market grew from $12.96 billion in 2022 to $13.85 billion in 2023. It's no wonder brands like Supergoop!, Kosas, Tula, Ole Henrikson, and Kopari all launched new sunscreen products this year.

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 the body sunscreen you're going to see on the beach: aerosol spray sunscreen.

Cosmetic chemist Michelle Wong went Instagram-viral 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 liquidized gases," said Wong. 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 Wong 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 Wong explains, most SPF tests are done on sunscreen without the propellant.

Pointing to a full-size bottle of aerosol SPF on her screen, Wong adds that some of the propellant also lands on the skin as liquid, 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.

The comments under Wong'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 and British Skin Foundation spokesperson. 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," Wong tells R29. "There's actually another study on spray sunscreens and wind, which found that you lose 32 to 79% of the sprayed sunscreen in 10 kph wind, and 28 to 93% for 20 kph wind. These are considered light and moderate wind conditions." In other words, most of the sunscreen might miss your skin entirely if the weather conditions aren't right.

We also consulted an NYC dermatologist to see if these studies are just as relevant for us U.S. sunscreen buyers — and the caution tracks.

"Generally speaking, I ask my patients to not use aerosol spray sunscreens, especially if they are chemical sunscreens," says Dr. Hamza Bhatti of Schweiger Dermatology Group. "The issue with aerosol sprays is that they contain propellants and chemicals that are not meant to be inhaled at all. When spraying the sunscreen, the distribution of sunscreen onto the body varies drastically. If the wind is blowing then a lot of the sunscreen never even reaches the skin. If a sunscreen has SPF 50 rating, less than half might actually reach the skin, which leads to unprotected sun exposure and increases the risk of skin cancer."

Aerosol spray sunscreens tend to be much lighter and dry down quicker, which make them great for reapplication of sunscreen. Additionally, in both Dr. Hussain and Dr. Bhatti's opinions, aerosol spray sunscreens are better than nothing. "Some people don't like the feeling of creams on their hands, which makes them greasy when they're at work, for example," says Dr. Hussain.

Wong says the amount you apply is important. "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." Wong 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. Dr. Bhatti's tip, if using aerosol sunscreens: Rub it in. "With aerosols, try to rub the skin evenly after you have applied it to ensure an even application," he says.

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 chemists and derms aren't too keen.

"They are very misleading and don’t provide great coverage at all," says Dr. Bhatti. Wong agrees: "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," Wong 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."

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 criticized powder SPF for being pricey.

In terms of application, Wong tells R29 that one popular skin-care 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 reapplication.

This depends on a few factors. "If you are in direct sun exposure, absolutely," says Dr. Bhatti. "At the beach, yes! Monitoring UV index is another way to gauge if you need to be re-applying. Sometimes those indexes are higher, and with enough movement and sun exposure, it may require reapplication."

Though Wong adds that you might be fine with a single application if you're not in direct sunlight. "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," she says.

If it's winter and you're heading to work when it's dark and coming back home when the sun has gone down, 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 reapply your sunscreen.

As for the right amount of sunscreen, half a teaspoon is usually recommended for your face and neck combined, and for each arm. Then 1 teaspoon on each leg, the front of your torso and the back of your torso — or, a shot glass full for your whole body.

​Sometimes, from a formula perspective. "There are a few minor differences because of possible ingredients," explains Dr. Bhatti. "Some sunscreens are mineral-based; some are chemical-based. They can affect cost. Another component is if they have additional ingredients such as niacinamide, which is good for people with acne, rosacea, or hyperpigmentation since it has antioxidants and anti-inflammatory properties."

Whatever formula you opt for, Dr. Hussian recommends an SPF of 50 and above — and something you enjoy wearing. "It's important to find one you like the color and the feel of," he adds, "because if you don't like it, you won't use it."

The aforementioned study on aerosol sunscreen came out of Australian research and Wong explains that other countries aren't publicly taking it into consideration just yet. But if you're invested in protecting your skin from the sun, which SPFs should you go for?

Wong likes Bondi Sands Sunscreen Lotion SPF 50+ Fragrance Free — a firm favorite among beauty editors and London-based 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 favorites is Ultraviolette Supreme Screen Hydrating Facial Skinscreen SPF 50+. "This is another Australian sunscreen with high protection that works really well as a makeup primer."

Those with acne-prone skin might want to choose something non-comedogenic (less likely to clog pores) as sunscreen has a reputation for being relatively thick. R29 favorites include the EltaMD UV Clear Broad-Spectrum SPF 46, ISDIN Photo Eryfotona Actinica Daily Mineral SPF 50+ Sunscreen, and Supergoop! Play Antioxidant Mist SPF 50 (a non-aerosol sunscreen).

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