Protection against Ultra-Long UVA

Today, UVB rays are known to cause sunburn and redness, while the more penetrating UVA rays contribute to skin aging, DNA damage and increased risk of skin cancer. Suncare formulations have therefore evolved to offer extended protection against UVA and UVB, including UVA1 (UVA-I), responsible for over 80% of solar UV received on Earth.

However, recent studies have demonstrated the harmful effects of UVA1 on skin lesions. Other articles, meanwhile, highlighted the lack of sunscreen products with ultra-long UVA protection (370-400 nm), which could be solved by a new UV protection including chemical or natural ingredients.

Given that there is no method specifically dedicated to Long UVA (or Ultra-Long UVA), nor regulated to guide consumers, WENEOS has pioneered the development of an in vitro method to assess protection in Long UVA (Ultra-Long UVA). It is a fully validated and impartial independent test.

days for an in vitro study with a final report

solar studies carried out


compliance with solar standards


We can assess the sun protection of your products in full compliance with official methods, or claim the properties of your products through exclusive tests developed by WENEOS.

Ultra-Long UVA protection

This innovative in vitro method is based on the principle of the international reference standard ISO 24443:2021, with adjustment to the in vivo SPF measured using a spectrophotometric method, while taking into account any potential photoinstability due to pre-irradiation.

The results of this measurement procedure can be used to calculate the UVA Protection Factor I (UPF-I), the Critical Wavelength (CW) and the UVA-I/UV ratio.

Finally, a pass/fail criterion is proposed based on the overall comparison of sun protection products to effectively claim UVA Long or UVA Ultra-Long protection.

(ref. HeUVA-LONG)

Published method : In progress

Discover the analyses additionalfor all-round sun protection

UV protection

  • SPF – UVB
  • UVA:UVB ratio
  • Photostability
  • Absorbance spectrum

Beyond UV

  • Ultra-Long UVA
  • Blue Light
  • Visible
  • Infrared
  • Full Spectrum
  • UVC


  • Water resistance
  • Sweat resistance
  • Sand resistance
  • Rub resistance
  • Wet Skin Application
  • Extreme conditions
  • Persistence | Long-lasting
  • Immediate protection