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Chemical sunscreens have evolved significantly since their initial creation in 1891. (Image credit: Getty Images)
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As the summer season in the U.S. intensifies, individuals are becoming more conscious of shielding their skin from the sun’s harmful effects. An additional option for this protection will soon be accessible.
On June 9, 2026, the U.S. Food and Drug Administration greenlit the very first new sunscreen ingredient permitted for non-prescription consumer use in the U.S. since 1999 – a compound known as bemotrizinol.
Bemotrizinol is not a novel substance; consumers in Europe and Asia have utilized it for many years. Its highly anticipated authorization and introduction to the U.S. sunscreen market are being celebrated by some.
As a biomedical engineer specializing in skin science, including the detrimental impacts of solar radiation, I aim to illuminate the function of bemotrizinol and its place among products currently available to consumers in the U.S. by exploring the physics of sunlight and sunscreens.
A short primer on sunlight
Our planet is illuminated by a star, a yellow dwarf located 93,000,000 miles away, which we affectionately refer to as the sun. It emanates light from its surface at an approximate temperature of 10,000 degrees Fahrenheit.
The Earth’s atmosphere effectively obstructs the majority of the sun’s radiant energy. Of the rays that penetrate this shield, approximately half are composed of infrared light – the source of the warmth felt on a sunny day – and 40% is visible light, commonly known as daylight.
Roughly 10% of these incoming rays are ultraviolet, or UV, light. UV light possesses the shortest wavelengths among the three types, rendering it the most hazardous. It is invisible and capable of causing harm to living tissues.
Ultraviolet damage
Scientists further classify solar UV light into distinct categories based on wavelength, measured in nanometers. Approximately 95% of it is UVA (ranging from 315-400 nm), and 5% is UVB (ranging from 280-315 nm). Sunscreens must be capable of preventing these rays from infiltrating the skin.
The sun also emits two other types of UV light – UVC (200-280 nm) and vacuum UV (100-200 nm) – but these are intercepted by the atmosphere, thus sunscreens typically do not need to possess the ability to block them.
Historically, scientists believed that only UVB rays posed a threat due to their role in causing sunburn; however, UVA radiation can also inflict damage upon the skin.
(Image credit: m.malinika/iStock via Getty Images Plus)
Previously, it was thought that only UVB rays were damaging, as they are responsible for sunburns. Current research, however, indicates that both types of UV radiation can harm the skin.
UVB, characterized by its shorter wavelength, carries more energy, whereas UVA can penetrate deeper into the skin. Both forms of UV radiation can compromise skin integrity, disrupt DNA structure, and contribute to the development of skin cancer.
The skin’s sole inherent defense mechanism against UV light is a microscopically thin layer of melanin, a pigment found in the epidermis. This pigment production increases upon sun exposure – the process known as tanning.
While this augmented melanin offers some protection, it is not absolute. Consequently, safeguarding your skin with sunscreen remains paramount.
Sunscreens old and new
Sunscreens are formulated in two distinct types: mineral and chemical.
The inaugural chemical sunscreen, conceived in 1891, was a preparation derived from quinine, a compound sourced from plants that imparts bitterness to tonic water.
Chemical sunscreens create a translucent coating on the skin, functioning akin to a solar sponge. They capture UV photons, undergo a benign chemical transformation, and then release the absorbed energy as heat. Bemotrizinol belongs to this classification.
Mineral sunscreens, such as those containing zinc or titanium oxide, deflect the sun’s rays by forming a protective film. This film primarily absorbs most UV light while reflecting a portion of it. Unlike chemical sunscreens, this film absorbs light inherently, without a chemical reaction, which often results in a visible white residue on the skin.
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Until now, the chemical sunscreens available in the U.S. have combined ingredients like avobenzone, the most prevalent UVA filter, with UVB filters such as octinoxate, octocrylene, octisalate, and homosalate. In synergy, these components provide comprehensive protection against the full spectrum of ultraviolet radiation.
These formulations offer protection for a limited duration due to degradation caused by their inherent chemical reactions, necessitating frequent reapplication.
Another crucial aspect of any sunscreen, whether mineral or chemical, is its Sun Protection Factor, or SPF. This numerical value indicates the extent to which a sunscreen prevents skin from burning – essentially, the proportion of UVB rays it absorbs.
An SPF of 2 signifies that a sunscreen halves your exposure to UVB rays, filtering out 50% of them. An SPF of 30 means the sunscreen allows only 1/30th of the rays to penetrate the skin, which equates to approximately 3.3%. Therefore, it effectively blocks about 97% of UVB rays.
Dermatologists generally endorse the use of sunscreen with an SPF of at least 30.
Benefits of bemotrizonol
While bemotrizinol is new to the U.S. market, the compound itself is not. European regulatory bodies approved it in 2000. It’s quite possible that if you have purchased sunscreen from abroad, perhaps during a trip to Mexico, Europe, Canada, or South Korea, you might already have some at home.
A significant advantage of bemotrizinol is its capacity to filter both UVA and UVB rays, eliminating the need for it to be blended with other components to achieve broad-spectrum protection.
It also possesses other favorable attributes. Primarily, its molecules tend to remain on the skin’s surface rather than being readily absorbed into the bloodstream, a phenomenon that can occur with certain other formulations.
Such absorption has sparked concerns about potential health risks associated with sunscreens, although these risks have not been substantiated in humans. Nonetheless, this aspect may deter some individuals from using them.
Furthermore, bemotrizinol demonstrates greater resistance to degradation from sun exposure compared to other chemical sunscreen agents. This photostability allows it to remain effective for four to eight hours, contrasting with the need for reapplication every couple of hours.
Irrespective of the specific type, as a skin scientist, I can confidently assert that any sunscreen application is superior to none. Your skin performs an exceptional role in shielding you from the external environment; therefore, it is essential to ensure you provide it with adequate protection in return.
This adapted article is re-published from The Conversation under a Creative Commons license. Access the original article here.
