It’s important to wear sunscreen. Sunscreen protects us from the damaging effects of UVA and UVB rays that wreak havoc on our skin cells, both in terms of health (cancer!) and aesthetics (wrinkles, sun spots etc). Thanks to a lot of important education around sun damage and the importance of SPF over the last few years, the popularity of sunscreen has soared, resulting in more offerings, sunscreen influencers, and even SPF make-up trends.

At the same time, however, we’re also seeing the rise of sunscreen sceptics, who have grown in numbers off the back of recalls, chemical sunscreen controversies and increasing societal mistrust of doctors and scientists. Many have turned to natural oils or methods to harness the sun. A lot of their fears can be scientifically disproved, but the one apprehension these cynics unanimously share isn’t scientific at all: an unshakeable fear of the government and pharmaceutical companies.

As a result, misinformation is thriving on social media platforms like TikTok. It’s a common problem for the site, but for this subject it has particularly dire consequences. In May, Cancer Research UK published that it expects skin cancer rates to rise for people between the ages of 25 to 49, with a seven per cent increase in new cases in the last ten years. More alarming is that researchers have projected a record high of 20,800 cases this year just in the UK.

Despite these warnings, the scepticism isn’t going away, and is only being exacerbated by influencers like Nara Smith, whose video creating a “DIY sunscreen” has been viewed 21 million times. To get to the bottom of the claims and theories swirling around about SPF, we tapped a few cosmetic scientists, skincare founders, and naysayers to figure out the facts.

DO BENZENE CONTAMINATIONS MAKE SUNSCREEN UNSAFE?

Short answer: No.

Long answer: In May 2021, a lab discovered that in a batch of 294 sunscreen products, 27 per cent were contaminated with benzene. While benzene is a naturally produced gas used to make everything from plastics to detergents, it’s a carcinogen restricted by the FDA for use in sunscreen because of its “unacceptable toxicity.” Products were swiftly recalled and taken off the market, and this incident has since become a calling card for sceptics.

However, we don’t actually need to worry about the presence of benzene, says cosmetic chemist Javon Ford, since “this was a contamination issue, not a sunscreen issue.” If you’re still uneasy, there’s an easy solution to elude any potential future benzene contaminations. “It usually forms in aerosolised products and those aren’t the best for proper coverage anyway,” Ford goes on. “Avoid aerosol sunscreen if you’re concerned.”

DO CHEMICAL SUNSCREENS CONTAIN HARMFUL INGREDIENTS?

Short answer: No. 

Long answer: While the ingredients used to produce chemical sunscreens – like oxybenzone, octocrylene, and avobenzone – allow for a thinner consistency and no white cast, the issue of safety is a concern that crops up a lot. It’s probably because of the way they work to block the sun: active ingredients are absorbed into the skin and then absorb UV rays, convert the rays into heat, and release them from the body. 

Cosmetic chemist Dr Michelle Wong says that concerns might also stem from studies conducted by the FDA in 2019 and 2020, which found that “sunscreen ingredients in the blood were at a higher level than they assumed automatically safe.” However, she also raises the point that because sunscreen is a drug, it gets studied and scrutinised “a lot more” than other products. “So more red flags show up even if overall there’s not that many.”

In 2022, the FDA released an update stating that these ingredients are indeed safe. “Regulatory agencies, including the FDA and European Commission, reviewed this data,” cosmetic chemist and PhD researcher Ava Perkins explains. “They continue to deem chemical and mineral UV filters safe at the levels currently used.” That being said, you can always opt for an alternative if you’re worried. “Even if you’re anti-chemical sunscreen, there are so many mineral sunscreen brands that use natural ingredients that might fit your philosophy,” Ford offers. 

DOES SUNSCREEN MESS UP OUR HORMONES?

Short answer: No, but it’s still being determined.

Long answer: Another often-cited fear is about the potential endocrine disruption caused by sunscreen. However, Perkins insists that this is a nuanced issue. “Studies have shown that UV filters can be absorbed through the skin and may have weak estrogenic activity, meaning it can mimic oestrogen in the body. However, the concentrations required to cause significant endocrine disruption are much higher than those typically found in sunscreen use.”

Dr Wong echoes Perkins’ comments. “It is an active area of research, but the current evidence doesn’t show any solid links to endocrine disruption in humans,” she assures. “I don’t think any scientist would say it’s impossible, but the evidence really doesn’t point that way.”

CAN YOU USE NATURAL OILS TO MAKE SUNSCREEN? 

Short answer: Don’t bother.

Long answer: Many people have decided to swap sunscreen for natural ingredients like beef tallow, coconut oil, carrot seed oil, raspberry oil and even butter. If you come across these videos on TikTok, you’ll see SPF levels assigned to many ingredients. Creators cite a 2010 study for SPF of most oils, while others use a 2024 study on the SPF levels of carrot seed oil. 

However, what they fail to mention (or understand) is that studying oils in vitro – which refers to being tested in a test tube – means it wasn’t tested on skin. “Reading scientific literature requires understanding methodologies used and whether the conclusions make sense for human use,” Perkins explains. Meanwhile, the 2024 study actually tests oils when added to a Neutrogena sunscreen with SPF 30. “If natural oils really had an SPF value of 30 or 40, we would be using them,” Ford quips.

When it comes to DIYing, the logic is that adding these oils together based on these SPF values can result in effective at-home sun creams. “I’m doing a PhD research project on this right now, and no, that’s not how it works,” Perkins explains. “Ingredients interact with each other in ways that are more complex than just simple addition. When combining a ‘natural’ SPF of 8 and 6 in vitro it didn’t give me SPF 14, but 8.”

CAN YOU USE ZINC OXIDE TO MAKE SUNSCREEN?

Short answer: No.

Long answer: Nara Smith used zinc oxide in her viral sunscreen DIY TikTok. Zinc oxide sits on top of skin, leaves a white cast, and is proven to scatter, reflect and absorb UVA and UVB rays. Though, it isn’t as simple as it seems. “There’s a cosmetic grade and then there’s the kind of zinc oxide you can get for paint,” Ford warns. “The paint version has high levels of lead.”

Then there’s the issue of mixing it. Not only do you need an industrial homogeniser to mix it properly, but it takes cosmetic chemists a really long time to get it right. “The problem with zinc oxide is that sun protection isn’t determined just by the amount, but also how it’s distributed,” Dr Wong explains. “Coverage is different if you have big round clumps versus an even spread of tiny particles. And uncoated non-nano zinc oxide loves to clump up. Sunscreen is one of the hardest products to formulate because of this.”

IS BUILDING A TOLERANCE TO THE SUN POSSIBLE? 

Short answer: No!

Long answer: Colorado-based holistic health practitioner Sara Parker’s journey with chronic vitamin D deficiency led her to become critical of sunscreen. She now uses small amounts of zinc sunscreen, and focuses on her diet, protective clothing and building her tolerance to the sun. “I try to expose my skin to the sun in small amounts starting in spring for 15 to 20 minutes each day, making sure I don’t burn so I build up melanin to help protect me.” 

However, skincare and skin health experts don’t recognise this as a legitimate method. “This is the debunked ‘base tan’ theory from when I was a kid,” Charlotte Palermino, owner of Dieux, says. “It’s like saying if you drink more, you build your tolerance. It’s true, but it isn’t good for you.” Dr Wong adds that, while the science of a tan providing protection is technically true, it can still lead to harm. “Tans contain melanin, which does act as a natural sunscreen, but it’s not very much – only like SPF 1 to 4 – and you’re damaging your skin to get that tolerance.”

DO THESE COMPANIES ONLY CARE ABOUT INCREASING THEIR PROFITS? 

Short answer: No.

Long answer: It’s not surprising that people are sceptical of the pharmaceutical industry – the Sacklers, Martin Shkreli, the Holmesburg Prison experiments and the diet pill industry, to name just a few, have worked hard to give it a bad name. As a result, more people than ever are beginning to question the safety of sunscreen, who’s in charge of making it, and how to take charge of our health. But Ford urges that while people are well within their right to be suspicious, they’re looking in the wrong direction.

“People don’t realise that the people making the sunscreens are not big pharma corporations. It’s regulated as a drug, but it’s not the pharmaceutical companies making it,” he says. “It’s usually cosmetic companies, the same companies they trust with their skincare and soap. They still trust other brands, why aren’t they trusting the sunscreen?”