Are high SPF sunscreens just a joke?
By Karl Roos - May 1, 2025
The truth about high SPF sunscreens
In the world of sunscreen, how things sound and reality are not always the same thing. SPF 100 might sound like the ultimate sun protection, but in reality, the difference between SPF 50 and SPF 100 is barely noticeable—while the risks and misleading claims are much greater.
Why high SPF sunscreens aren’t more effective
Most people assume that SPF 100 provides double the protection of SPF 50, but that’s not the case at all. SPF ratings measure the percentage of UVB rays blocked, but the increase in protection above SPF 30 is marginal. This is explained by the fact that the scale was firstly made with SPF 30 as the maximum value:
- SPF 30 blocks 97% of UVB rays (Which dermatologists agree is enough for all situations of sun protection)
- SPF 50 blocks 98%
- SPF 100 blocks 99% (at most)
That’s just a 1% difference between SPF 30 and 50 and another 1% between SPF 50 and SPF 100, but the marketing makes it seem like a game-changer. Things are clearly not always as they look.
The hidden problem: UVA rays
SPF ratings only measure UVB protection (the rays responsible for sunburn), not UVA rays, which penetrate deeper into the skin and cause long-term damage, premature aging, and increased skin cancer risk.
Unlike UVB rays, which cause visible burns, UVA rays are more insidious—they penetrate deeper into the skin, contributing to photoaging, wrinkles, and potentially DNA damage that increases cancer risk over time.
This means that a simple SPF rating, be it 30 or 100, actually does not tell you about the UVA protection of that sunscreen.
How Is UVA protection measured?
UVA protection is assessed using different standards, depending on the regulatory framework of a country. The most common method include:
⇒ The UVA-PF Test (Persistent Pigment Darkening – PPD Test): Measures how much UVA radiation is needed to produce prolonged darkening of the skin. A product must provide at least 1/3 of the labeled SPF in UVA protection to qualify as broad-spectrum.
However, studies by the Environmental Working Group (EWG) have shown that many high SPF sunscreens fail to meet adequate UVA protection standards. In some cases, high SPF products only provide a quarter of the UVA protection needed, leaving the skin highly vulnerable.
The false sense of security
High SPF sunscreens encourage risky sun behavior. People tend to apply less sunscreen, reapply less frequently, and stay in the sun longer because they think they’re getting significantly more protection. In reality, they’re increasing their exposure to harmful UVA radiation without realizing it.
The EWG also found that many high SPF products didn’t even deliver the UVB protection stated on their labels—some only provided 42-69% of the promised protection. This issue was significantly more prevalent in high SPF sunscreens (SPF 50+) than low SPF sunscreens. So not only does the high SPF number give a false sense of security, it’s also significantly more likely to not even provide the protection that it does state.
The health risks of high SPF sunscreens
To achieve SPF levels above 50, manufacturers often increase the concentration of chemical UV filters.
This can lead to:
⇒ Skin irritation & allergic reactions
⇒ Hormone disruption from certain chemical filters
⇒ Higher absorption of chemicals into the bloodstream
⇒ Potential endocrine disruption: Some chemical UV filters, such as oxybenzone and octinoxate, have been found to mimic hormones and interfere with the body’s natural hormonal balance, potentially leading to reproductive issues and thyroid dysfunction.
⇒ Increased risk of skin sensitivity: Certain high SPF formulations contain higher concentrations of active ingredients that may trigger skin irritation, allergic reactions, and contact dermatitis, especially in individuals with sensitive skin.
⇒ Chemical accumulation in the body: Research has shown that some sunscreen chemicals can be detected in the bloodstream long after application, raising concerns about their long-term effects on human health.
Why more chemical filters are used in high SPF sunscreens
Manufacturers must use higher concentrations of chemical UV filters to achieve SPF levels above 50. This is because no single ingredient can block enough UVB rays on its own to reach SPF 100, so a combination of multiple filters is necessary. These higher concentrations come with increased risks, including greater chances of skin irritation, allergic reactions, and hormone disruption.
This practice is not necessarily in the best interest of the consumer but is often a marketing strategy. High SPF labels give the illusion of superior protection, convincing consumers that SPF 100 is significantly better than SPF 50. However, as previously mentioned, the difference in UVB protection is minimal, while the risks and misleading claims are far greater. The increased use of chemicals also raises concerns about long-term health impacts and environmental damage.
The environmental impact
Most high SPF sunscreens rely on chemical UV filters that have been linked to coral reef damage and marine toxicity. Several destinations, including Hawaii and Palau, have banned certain sunscreen chemicals due to their harmful effects on marine life.
In fact, the majority of SPF 50+ sunscreens contain ingredients such as oxybenzone, octinoxate, and octocrylene, which have been deemed illegal in places like Hawaii and Palau due to their role in coral bleaching and aquatic toxicity. These chemicals have been found in marine ecosystems, affecting the reproductive health of marine life and contributing to environmental degradation.
Because achieving SPF levels above 50 requires increasing the concentration of these chemical filters, most high SPF sunscreens are not compliant with the environmental regulations in these regions. This suggests that the pursuit of SPF 100 is not only unnecessary but also actively harmful to marine biodiversity.
Unreliable SPF testing
SPF testing isn’t standardized across labs, leading to inconsistent and often misleading results. Studies have found that minor variations in application can result in SPF 100 sunscreens testing anywhere from SPF 37 to SPF 75 in real-world conditions. Further contributing to the uncertain nature of using high SPF products.
What do experts recommend?
The case for an SPF 50+ cap
The FDA has long considered SPF values above 50 to be “inherently misleading.” Most countries have already capped SPF at 50+. In 2011, the FDA proposed banning labels higher than SPF 50, but in 2021, they suggested increasing the limit to SPF 60+.
The EWG and other experts argue that capping SPF at 50+ would prevent misleading claims and encourage better sun protection habits.
The bottom line
SPF 100 isn’t the superhero it pretends to be. It provides minimal extra protection, encourages risky sun behavior, contains more potentially harmful chemicals, and misleads consumers into a false sense of security. Instead of chasing high SPF numbers, opt for broad-spectrum SPF 30-50, reapply regularly, and use sun-protective clothing for the best defense against sun damage.
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About the author
Karl is one of the co-founders of Suntribe and serves as the Head of Sales. As a passionate longboarder, Karl loves dancing on big and small waves around the world. After spending six years in Australia using natural sunscreen, he returned to Europe only to find a lack of suitable options—so he began making his own. This was the beginning of Suntribe. Known for his daily use of obscene amounts of regular Zinc, Karl’s favorite product remains the 45g Zinc Tin which he layers like a second skin!
