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Macro shot of liquid UV filter testing and cosmetic lotion sample in a modern chemical compliance laboratory, clean clinical daylight, deep slate blue tones
Macro shot of liquid UV filter testing and cosmetic lotion sample in a modern chemical compliance laboratory, clean clinical daylight, deep slate blue tones

Cosmetic Safety

DHHB and DnHxP in sunscreen: safety and hazards

What makes a sunscreen effective? Its primary function is, of course, to protect the skin from harmful ultraviolet (UV) radiation, particularly the high-energy radiation that can contribute to skin cancer. This is especially relevant during periods of intense sunlight and high temperatures, such as those we are currently experiencing. To provide effective protection, sunscreens must contain substances that strongly absorb radiation in the UV range (100–400 nm), particularly in the 280–400 nm range. When applied to the skin, these substances absorb UV radiation and thereby help protect the skin from its harmful effects.

Chemical composition

The UV absorption of DHHB and the contamination of DnHxP

One such substance is diethylaminohydroxybenzoylhexylbenzoate (DHHB), an effective UV-A absorber with a maximum absorption wavelength of 354 nm. It also exhibits excellent thermal stability, making it more resistant to degradation than many other UV filters. However, DHHB may contain an important contaminant, di-n-hexyl phthalate (DnHxP) [1, 2]. DnHxP is a potent reproductive toxicant in males (Repr. 1B under the harmonized CLP classification) and has been included in the Authorisation List under the REACH Regulation.

Unfortunately, a study conducted by the University of Copenhagen found DnHxP in 84% of the more than 1,500 individuals tested [2]. The presence of the substance is thought to be associated primarily with the use of sunscreens containing DHHB, even though DnHxP is not declared as an intentionally added ingredient.

Close-up of European chemical safety assessment report documents and laboratory testing vials, cool daylight, deep slate tones
Close-up of European chemical safety assessment report documents and laboratory testing vials, cool daylight, deep slate tones

SCCS statement

Safety limits and manufacturer goals

According to the Scientific Committee on Consumer Safety (SCCS) [1], sunscreen products containing up to 10% DHHB are considered safe, provided the DNHXP level in the raw material does not exceed 260 ppm (0.026%). The assessment also notes that reducing this impurity to 1 ppm (0.0001%)—a general target often set for manufacturers—is currently not feasible.

Source:
[1] https://lnkd.in/e_Abe-if
[2] https://lnkd.in/eascAM-z