Contrary to the old adage, there is something new under the sun after all – at least here in the United States. For the first time in 27 years, the U.S. Food and Drug Administration has approved a new active sunscreen ingredient for over-the-counter use.

It’s a chemical called bemotrizinol (“beh-moh-TRIZ-in-ol”), also referred to as BEMT, and it offers major advantages over presently available U.S. sunscreens, according to three Stanford Medicine dermatologists.

Here’s what these experts on skin protection and ultraviolet radiation had to say about this new product, due to hit shelves in September.

What, exactly, is bemotrizinol?

Bemotrizinol was developed by Swiss chemists seeking better sunscreens in the 1990s. (Formula C38H49N3O5 for the chemistry geeks out there.)

It’s oil-soluble, meaning bemotrizinol would absorb into our oil-rich skin except for the fact that it is a big molecule. Instead, bemotrizinol is minimally absorbed through the skin and adheres well to our bodies, forming a layer that absorbs ultraviolet light from the sun and converts it to harmless heat.

What makes bemotrizinol different from sunscreens already available?

From the pure standpoint of protecting our skin from the sun, bemotrizinol is a “game changer,” said Susan Swetter, MD, the Mosbacher Professor in Dermatology, co-director of the Melanoma and Cutaneous Oncology Programs at Stanford Medicine and the Stanford Cancer Institute. “It’s the best broad-spectrum ultraviolet radiation filter available.”

Most sunscreens claim to offer broad-spectrum coverage, meaning they absorb both kinds of ultraviolet light – dubbed UVA and UVB – that reach ground level and damage our skin. But available U.S. sunscreen filters do not cover the full spectrum of UVA, meaning a portion of this skin-penetrating light goes unchecked. “We have not had a good UVA filter on the U.S. market to date,” said Joyce Teng, MD, PhD, a professor of dermatology and director of Pediatric Dermatology at Stanford Children’s Health.

To be more specific:

• Ultraviolet A (UVA) has a wavelength of 315-400 nanometers (billionths of a meter). About 95% of the ultraviolet radiation at the Earth’s surface is UVA. A lower-energy form of ultraviolet light, UVA more easily penetrates the skin and primarily causes photoaging, meaning wrinkles and sagging. Rahman notes it’s important to remember UVA is also a cause of skin cancer, as demonstrated since the late 1980s when people had higher rates of skin cancer on the driving side of their face due to UVA penetration.
• Ultraviolet B (UVB) has a wavelength of 280-315 nanometers and comprises the remaining 5% of ground-level ultraviolet. Being more energetic than UVA, UVB wreaks greater amounts of havoc through the top layer of skin, primarily causing sunburn and directly damaging DNA, significantly increasing cancer risk.

Sunscreens historically available in the U.S. have provided UVA coverage only out to about 370 nanometers. Bemotrizinol covers the whole UVA spectrum, out to 400 nanometers. “Bemotrizinol is a huge step forward compared to so many other things we’ve had,” said Zakia Rahman, MD, a clinical professor of dermatology and director of the resident laser and aesthetic clinic at Stanford Medicine.

Why did it take so long for bemotrizinol to be approved in the U.S.?

Chalk it up to different regulatory structures. Unlike most of the world, which treats sunscreen as an over-the-counter cosmetic, the U.S. has historically classified sunscreen as an over-the-counter drug. Accordingly, to be sold in American stores, sunscreens must go through strict regulatory approval for safety – including human testing – as well as efficacy and clear labeling. This is so consumers can easily understand how to safely administer the product themselves.

Those extra regulatory steps, plus bureaucratic rigamarole, held up ingredient approval for more than two decades. This involved legislation such as the Sunscreen Innovation Act from 2014 to create an official regulatory pathway for bemotrizinol review, and eventually the Coronavirus Aid, Relief, and Economic Security (CARES) Act of 2020 to modernize the over-the-counter drugs regulatory framework.

“I don’t want to say ‘battle,’ but it’s certainly been a greater-than-20-year effort to get superior ultraviolet filters incorporated into our sunscreens,” Swetter said.

Should I be concerned that the FDA took so long to approve bemotrizinol?

No, quite the opposite, the Stanford Medicine experts said. “We have waited a really long time to have a new sunscreen option that’s better at UVA protection. On the plus side, there’s been added protection for consumers because of the testing process,” said Rahman, building on the safety history of bemotrizinol since its introduction in other countries circa 2000.

As part of its review, the FDA considered animal studies that showed no evidence for increased cancer risk or endocrine disruption, which is when substances interfere with natural hormonal systems, often manifesting as reproductive changes in parents or developmental issues in offspring.

Human testing of the 6% bemotrizinol concentration approved in the U.S. also found no signs of concerning skin irritation. Skin absorption, especially in pregnant women and children, was another significant concern, but testing ruled that out as well. “Since the bemotrizinol molecule is large, it does not cross the skin barrier easily, so that minimizes risk of systemic absorption,” Teng said.

Overall, the FDA approved the chemical not only for sunscreens for adults but also for children as young as 6 months. That could prove critical for bringing down skin cancer rates in subsequent generations.

“Bemotrizinol is tried and true, and its FDA approval is great news for consumers,” Swetter said.

Besides keeping me safe from UV light, what else is good about bemotrizinol?

• Long-lasting protection. Bemotrizinol is highly photostable, meaning it doesn’t degrade as readily as other sunscreen filters while getting blasted by solar radiation. That’s in contrast to other chemical sunscreens in the U.S. such as avobenzone, which “breaks down in the sun after about 30 minutes,” said Swetter, and must be “stabilized with yet another chemical filter called octocrylene,” which, while providing photostability, still doesn’t protect beyond the aforementioned UVA 370 nanometer mark.
• No need to slather on as much. Because people can wear bemotrizinol “for longer and it won't break down as a result of ultraviolet light exposure, that means the amount applied won’t feel greasy or thick,” Rahman said. “That’s part of what makes it cosmetically elegant.” Swetter added that reapplication is still recommended about every two hours, though.
• Less greasy. Because bemotrizinol sops up so much UV all on its own, products containing it do not need to include stabilizers, oils, and other ingredients that contribute to that slippery feeling of some sunscreens.
• Transparent. Mineral sunscreens, such as titanium dioxide and zinc oxide, form a physical barrier on top of the skin, deflecting UV radiation. But these minerals leave a white cast that some consumers don’t like. And, while sunscreen companies offer “micronized” versions of these minerals that are smaller, less visible, and can even be tinted to match different skin tones, Rahman said a persistent issue is that the sunscreens can “still rub off on your clothes and be hard to wash off.” Bemotrizinol does not cause these kinds of problems. However, Rahman adds that FDA-approved tinted mineral sunscreens are also an important tool for people who have pigmentary disorders such as melasma because they block high-intensity visible light. “Don’t throw away your tinted mineral,” she said. “Use it as your top layer of sunscreen.”
  

Is bemotrizinol considered “reef safe”?

“Reef safe” is a marketing term with no standardized or regulatory definition in the sunscreen space, Rahman said, but the idea that some products are responsible for marine ecosystem degradation is not without merit. Studies have linked some currently approved sunscreens – namely oxybenzone and octinoxate – to coral reef bleaching and harm to the DNA of certain species.

Accordingly, starting in 2019, multiple jurisdictions, including Key West, Florida, the state of Hawaii, and the nation of Palau, banned the sale and distribution of sunscreens containing those chemicals and others to protect their reef systems.

On top of this environmental hazard, oxybenzone and octinoxate are becoming less used due to concerns over endocrine disruption in marine life and even humans, Rahman said.

Against this backdrop of legitimate concern regarding chemical sunscreens, the Stanford Medicine researchers said they were not aware of evidence suggesting that bemotrizinol is harmful to the environment.

How can I get sunscreen that contains bemotrizinol and will it cost more?

The company bringing bemotrizinol to the American market, Swiss-Dutch multinational DSM-Firmenich, has announced it will start selling its bemotrizinol formulation in August under the brand name Parsol Shield for incorporation in U.S. sunscreens, with the first products containing the filter to be available starting in September.

To demonstrate efficacy, tolerability and safety, the company reportedly spent at least $18 million over two decades to satisfy FDA regulators, including by conducting studies involving nearly 500 people “representing the diversity of the U.S. population.”

Regulators have granted DSM-Firmenich exclusive U.S. marketing rights to sell the ingredient for 18 months to help it recoup the investment. As for the price tag for bemotrizinol-containing products versus legacy sunscreens, that remains to be seen.

To that end, the Stanford Medicine experts point out that U.S. consumers can already buy high-quality and affordable bemotrizinol products from overseas through various websites, as well as scoop them up when abroad. “Whenever I travel overseas, I’ll grab sunscreens that I know we can’t get here,” Rahman said.

Of note, in addition to bemotrizinol, many foreign sunscreen products include or rely on other filters still not available domestically. Examples include Tinosorb M, Mexoryl, and Uvinul. Those extra ingredients have similar cosmetic elegance, safety, and efficacy profiles as bemotrizinol, and offer stronger ultraviolet absorption at certain wavelengths to enhance broad-spectrum filtration, Swetter said. (Bemotrizinol’s peaks are at 310 and 340 nanometers.)

The upshot is the creation of a stronger layering effect. “When you add in these other filters, you have multiple overlapping peaks of ultraviolet wavelength absorption, and that gives you longer and better protection,” Swetter said. “So, I’m hoping now that bemotrizinol has been approved, maybe we’ll see some of these other excellent filters make it to market.”

What could this mean for sunscreen-wearing compliance and skin cancer incidence?

Dermatologists are thrilled because they think the cosmetic advantages of bemotrizinol will boost sunscreen use overall, delivering full-spectrum ultraviolet radiation protection to Americans for the first time.

“If you have a sunscreen that’s going to stain your clothes or leave a white cast on your skin, or if it’s going to be greasy, most people don’t want to wear it,” Rahman said. “You need to reduce the barrier to entry, and bemotrizinol does that.”

For little kids aged 2 and younger, pediatricians often previously recommended mineral sunscreens instead of chemical sunscreens containing avobenzone and oxybenzone. With bemotrizinol’s long track record of safety and effectiveness and FDA approval for children six months and older, Swetter said that encouraging sunscreen application by parents could have a transformative effect.

Risk models have shown that “if we start the regular use of sunscreen and other sun-protective measures in the first 18 years of life, we could reduce skin cancer rates by about 80% in adulthood,” she said. “Starting young is going to be really important, and the recent FDA approval of bemotrizinol is very exciting.”