Bemotrizinol Sunscreen: The First New US UV Filter in 25 Years

For the past quarter century, US sunscreen formulators have worked with a filter palette frozen in 1999. While European and Asian regulators approved a generation of high-performing UV filters in the 2000s and 2010s, the US OTC monograph stayed closed, leaving American consumers with avobenzone as the only meaningful UVA absorber in chemical sunscreens. On December 11, 2025, the FDA proposed amending Over-the-Counter Monograph M020 to add bemotrizinol — a broad-spectrum triazine filter Europeans have used for two decades — at concentrations up to 6 percent. The proposed order is the first new sunscreen active the agency has authorized since the late 1990s, with a final order expected by late 2026. This piece audits the chemistry, the photostability case, and what the addition will and will not change for American photoprotection. ## Key Takeaways - **First New US UV Filter Since 1999:** The FDA proposed adding bemotrizinol to the OTC sunscreen monograph at concentrations up to 6 percent in December 2025; a final order is expected mid- to late 2026. - **Broad-Spectrum Triazine Chemistry:** Bemotrizinol absorbs across UVB and UVA with peaks near 310 and 340 nm, covering the UVA1 range where most current US monograph filters fall short. - **Photostable and Stabilizing:** Independent testing reports more than 98 percent of bemotrizinol intact after 50 minimal erythemal doses; it also stabilizes avobenzone, the workhorse US UVA filter that degrades within roughly thirty minutes of sun exposure on its own. - **Low Systemic Absorption:** The molecule's high molecular weight near 628 daltons and lipophilicity keep dermal penetration low, which is the safety case the FDA's scientific review cites. - **Closes Part of the US-to-EU Gap:** Bemotrizinol has been formulated into European and Asian sunscreens for more than twenty years; US approval narrows but does not entirely eliminate the photoprotection gap that drives American consumers to import abroad. ## What the FDA Actually Proposed The proposed administrative order, designated OTC000039, would amend the OTC monograph to permit bemotrizinol — formally bis-ethylhexyloxyphenol methoxyphenyl triazine, sometimes shortened to BEMT — at concentrations up to 6 percent in sunscreen products with a labeled SPF of at least 2. The filter would be allowed across the standard dosage forms: oils, lotions, creams, gels, butters, pastes, ointments, sticks, and non-aerosol sprays. The proposal followed a Tier 1 Order Request submitted by DSM Nutritional Products LLC, which holds the original safety dossier and has marketed the ingredient outside the US since approximately 2000. The procedural moment matters because of how rare it is. The OTC sunscreen monograph has been functionally closed since 1999. Several proposed filters — including ecamsule (Mexoryl SX), enzacamene, and amiloxate — have sat in regulatory limbo for two decades despite long-standing approval and use in Europe, Canada, Japan, and Korea. The FDA's 2019 proposed rule under the Sunscreen Innovation Act effectively reopened safety questions for nearly every existing filter, slowing rather than accelerating approval. The December 2025 proposed order is the first instance in which the agency has worked through the safety review and concluded that a new active ingredient meets the generally recognized as safe and effective (GRASE) standard for OTC monograph inclusion. The public comment period closed January 26, 2026. Subject to the comment review and any modifications the FDA elects to make, a final order is expected mid- to late 2026, with the first US-formulated bemotrizinol sunscreens reaching shelves shortly after. ## The Chemistry: Why Triazines Cover What Avobenzone Misses Bemotrizinol absorbs UV across a broad range from approximately 280 to 400 nanometers, the full span covered by UVB (280–315 nm) and UVA (315–400 nm). Its molar extinction profile shows two absorption peaks: one near 310 nm in the UVB region, and a second near 340 nm extending into UVA2 and partially into UVA1. The UVA1 band, roughly 340–400 nm, penetrates deepest into the dermis and drives much of the photoaging cascade as well as immunologic effects associated with prolonged sun exposure. Most US monograph filters absorb strongly in UVB and short UVA but drop off through UVA1; avobenzone is the main exception in the current US formulary, with peak absorbance near 357 nm. The triazine ring at the center of the bemotrizinol molecule is the structural source of its photostability. After absorbing a UV photon, the excited molecule dissipates the energy through intramolecular vibration and ring resonance rather than through bond cleavage. Practical consequence: it does not photodegrade meaningfully under field exposure. Published testing shows more than 98 percent of bemotrizinol remaining intact after exposure equivalent to 50 minimal erythemal doses. By comparison, avobenzone loses roughly half its protective capacity within about 30 minutes of direct sun exposure when used without a photostabilizer. The stabilizing effect on other filters is the second relevant property. When bemotrizinol is co-formulated with avobenzone, the triazine ring accepts excited-state energy from the avobenzone molecule and dissipates it harmlessly, preserving the avobenzone's UVA absorbance over longer exposure windows. The same effect appears in the bemotrizinol-octocrylene-avobenzone triad common in European formulations. For US formulators currently relying on octocrylene as the primary avobenzone stabilizer, bemotrizinol opens a second photostabilization path with broader spectral coverage. ## The Safety Case the FDA Cited The FDA's scientific review accompanying the proposed order rests on three pillars. The first is the molecular weight argument. Bemotrizinol's molecular weight is approximately 628 daltons, well above the conventional 500-dalton threshold below which dermal penetration of small molecules becomes more efficient. The molecule is also highly lipophilic, which keeps it associated with the upper stratum corneum lipid matrix and limits movement into the viable epidermis and dermis. Animal and human pharmacokinetic studies referenced in the dossier showed plasma levels at or below the limit of quantification under intended-use conditions. The second pillar is the European safety record. Bemotrizinol has been approved for use in European sunscreens since approximately 2000 and is present in widely used products across the EU, UK, and Asia at concentrations up to 10 percent in some jurisdictions. Two decades of post-market surveillance has not produced significant safety signals around endocrine disruption, contact sensitization at rates above background, or photoallergic reaction at clinically relevant frequencies. The accumulated real-world record is one of the strongest non-trial datasets the FDA could weigh. The third pillar is the irritation profile. Patch testing and clinical use data report a low incidence of cutaneous irritation, comparable to or better than several existing US monograph filters. The molecule does not appear to trigger photoallergic reactions at rates above placebo in published reviews. The FDA's review acknowledges remaining uncertainty around long-term endocrine effects at higher exposure scenarios, which is the same uncertainty that hangs over most chemical UV filters and which the agency has handled through ongoing post-market study requirements rather than blanket restriction. ## What Will and Will Not Change for US Sunscreen Formulation US-formulated chemical sunscreens are likely to see meaningful improvement in three dimensions once bemotrizinol is approved and incorporated. UVA1 coverage will extend further into the long-wavelength UVA range than is reliably achievable with the current US filter set alone. Photostability of the avobenzone-based UVA backbone will improve, reducing the need for high-percentage octocrylene and the formulation trade-offs that octocrylene imposes around skin feel and emulsion stability. Overall critical wavelength — the regulatory measure of broad-spectrum coverage — should rise across formulations that incorporate bemotrizinol, supporting broader compliance with broad-spectrum labeling. What will not change is the full US-EU gap. Several modern European filters remain unapproved in the US, including bisoctrizole (Tinosorb M), tris-biphenyl triazine (Tinosorb A2B), and methoxypropylamino cyclohexenylidene ethoxyethylcyanoacetate, marketed as Mexoryl 400, the long-UVA1 specialist behind La Roche-Posay's Anthelios UVMune 400 line. Each of these filters covers spectral regions or offers properties that bemotrizinol alone does not fully replace. For consumers prioritizing maximal UVA1 coverage in a single formulation, European sunscreens combining bemotrizinol with one of these additional filters will retain a meaningful edge. The realistic positioning is that bemotrizinol approval closes part of the gap, not all of it. The pattern matters for how the SkinCareful reader should weigh sunscreen choices over the next two years. For users who currently use US chemical sunscreens and have been content with avobenzone-based formulations, the first bemotrizinol-formulated products are likely to offer measurable improvement in UVA stability without changing the overall use experience. For users who have been importing European or Korean sunscreens specifically for superior UVA1 coverage, the import case weakens but does not collapse. ## The Honest Verdict for the SkinCareful Reader The December 2025 proposed order is the most consequential US sunscreen regulatory action in 25 years. The science behind it is solid: bemotrizinol is a well-characterized triazine filter with a long European safety record, a photostable absorption profile that extends coverage into UVA1, and a co-stabilization effect on avobenzone that addresses one of the persistent weaknesses of US chemical sunscreens. The FDA's scientific review treats the safety case as sufficient under the GRASE standard. For the SkinCareful reader, the practical implication is patience and selectivity. Final order timing in mid- to late 2026 means US formulations are likely to appear in late 2026 and through 2027, with the first generation probably from brands already importing European technology platforms. Reading the formulation, not the marketing, will be the test: bemotrizinol pulls its weight at concentrations toward the higher end of the 6 percent cap, and is most valuable when paired with the avobenzone and octocrylene backbone rather than replacing them. Until then, European and Korean multi-filter sunscreens remain the strongest option for users who want maximal photoprotection today. ## Frequently Asked Questions ### What is bemotrizinol and why is it significant? Bemotrizinol, also written as bis-ethylhexyloxyphenol methoxyphenyl triazine or BEMT, is a broad-spectrum organic UV filter that absorbs both UVB and UVA radiation with peaks near 310 and 340 nanometers. It is significant because in December 2025 the FDA proposed adding it to the US sunscreen monograph at concentrations up to 6 percent, the first new sunscreen active the agency has proposed in approximately 25 years. ### How does bemotrizinol compare to avobenzone? Avobenzone has been the dominant UVA filter in US sunscreens but is photolabile, losing roughly half its protective capacity within 30 minutes of sun exposure unless paired with a stabilizer like octocrylene. Bemotrizinol is photostable, retaining over 98 percent of its intact molecule after 50 minimal erythemal doses in published testing, and it also acts as a photostabilizer for avobenzone when the two are combined. Bemotrizinol also extends protection further into the UVA1 range. ### Is bemotrizinol safe? The FDA's scientific review supporting the December 2025 proposed order concluded that bemotrizinol exhibits low systemic absorption and a low incidence of skin irritation. Its high molecular weight, near 628 daltons, limits dermal penetration. The ingredient has been in commercial European and Asian sunscreen formulations for more than 20 years without major safety signals, which informed the FDA's review. ### When will US sunscreens with bemotrizinol be available? The FDA proposed order was published December 11, 2025, with a public comment period that closed January 26, 2026. A final order is expected mid- to late 2026. US-formulated sunscreens containing bemotrizinol could begin reaching the market shortly after the final order, with broader formulation rollouts likely through 2027. ### Should I still buy European sunscreens that already contain bemotrizinol? European sunscreens such as La Roche-Posay Anthelios UVMune 400 already use bemotrizinol alongside other filters not yet approved in the US, including Tinosorb M and Mexoryl 400. For users prioritizing UVA1 coverage today, European formulations remain meaningful. Once US bemotrizinol formulations arrive, the gap will narrow on UVB and short-wavelength UVA but European multi-filter products may still offer broader UVA1 coverage.