Though preventing sunburn was their original purpose, modern sunscreens are no longer designed solely to protect against erythema. Photoprotection has evolved from a predominantly UVB-driven shield toward broad-spectrum protection against the diverse forms of UVB- and UVA-induced damage. In addition, modern sunscreen formulations also must meet a wide range of consumer expectations regarding aesthetics and application formats to encourage regular and adequate use.
In this context, Tinosorb® S (USAN: Bemotrizinol) has become a leading UV filter in sunscreen formulations. Developed at Ciba Specialty Chemicals through extensive screening of hydroxyphenyl triazine derivatives, and later integrated into BASF through acquisition, Tinosorb S has established itself as a benchmark broad-spectrum, photostable UV filter.
Effective August 2026, Bemotrizinol (BEMT), marketed by BASF as Tinosorb S, was officially approved for the US market as a sunscreen active ingredient by the FDA.1 BASF holds co-exclusive rights during the FDA’s 18-month exclusivity period for new sunscreen actives, under a licensing agreement with DSM Nutritional Products, LLC, including for sunscreen products manufactured in or imported into the United States. Used globally for decades, the incorporation of Tinosorb S into sunscreen formulations for the US market is supported by BASF’s extensive sun care expertise and broad portfolio of sunscreen formulation ingredients.
The strong absorption profile of Tinosorb S spans both the UVB and UVA wavelengths, providing highly effective and balanced UV protection. It also helps stabilize photounstable UV filters such as avobenzone, helping maintain performance during sun exposure while minimizing the formation of undesirable photoproducts and potential risks. Furthermore, its favorable safety profile and molecular weight above 500 Da are also predictive of low skin penetration potential.
As sunscreen users differ in age, skin sensitivity, lifestyle, and aesthetic preferences, the concept of a universal “one-size-fits-all” sunscreen is increasingly unrealistic. Tinosorb S addresses this challenge through its oil solubility and excellent compatibility with multiple formulation technologies. It can be incorporated into virtually all formats, including lotions, creams, gels, sticks, sprays, and transparent systems, enabling formulators to develop tailored sunscreens.
For children, sunscreens based on inorganic UV filters such as titanium dioxide and zinc oxide have traditionally been recommended.2 3 However, achieving the highest SPF levels together with strong UVA protection using only inorganic filters remains challenging, and such formulations may also leave a visible white cast on the skin. Hybrid formulations that combine Tinosorb S with inorganic UV filters can enhance protection while minimizing these drawbacks. Additionally, the only active UV filters with FDA full classifications as GRASE (Generally Recognized as Safe and Effective) are the inorganic UV filters (zinc oxide and titanium dioxide) and BEMT.
Daily photoprotection requires reliable, broad-spectrum UV defense. With its high efficacy and photostability, Tinosorb S provides a strong foundation for daily-use formulations that help mitigate premature photoaging while maintaining excellent sensory properties.
Another increasingly popular use-case is transparent sunscreens, notably clear mist sprays, which are valued for their easiness to apply and invisible finish. Achieving high SPF levels in clear systems is however challenging, making Tinosorb S key to establishing broad-spectrum UV protection in such systems.
For oil-soluble crystalline filters such as Tinosorb S, emollient selection is an important part of formulation design. Cetiol® emollients, including Cetiol B, Cetiol ABV, and Cetiol CC, can facilitate filter incorporation, support a homogeneous oil phase, and help formulators optimize skin feel, spreadability, and cosmetic elegance across a range of product formats and textures.
By combining access to Tinosorb S with Cetiol emollients, complementary formulation-enabling ingredients, application know-how, and technical support, BASF can help customers develop complete sun care solutions that balance protection, stability, sensory performance, and formulation flexibility.
More than two decades after its introduction, Tinosorb S remains a cornerstone of sunscreen innovation, combining efficacy, photostability, safety, and formulation versatility. Combined with BASF’s portfolio of Cetiol emollients, UV enhancers, and formulation expertise, it enables innovative sun care solutions.
Footnotes:
1 BASF launches Tinosorb S in the United States
2 Gilaberte Y, Carrascosa JM. Sun Protection in Children: Realities and Challenges. Actas Dermosifiliogr. 2014;105(3):253–262. [actasdermo.org]
3 De Marco A, Romita P, Ambrogio F, Foti C, Bonamonte D. Children and Sunscreen Use: Between Skin Cancer Prevention and Cosmetology. IFSCC Magazine. 2022;25(2)
