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Evaluating the UVA protection of sunscreens
R Roelandts1, N Sohrabvand, M Garmyn
1Department of Dermatology, University of Leuven, Belgium.
Journal of the American Academy of Dermatology
|July 1, 1989
Summary
Determining the UVA protection factor of sunscreens is crucial. This study compared five methods, finding they all offer quantitative UVA protection estimates, but results vary by method and reading time.
Area of Science:
- Dermatology
- Photobiology
- Cosmetic Science
Background:
- Sunscreens primarily indicate UVB protection, leaving UVA protection factors largely unknown.
- UVA radiation contributes to skin aging and cancer, necessitating accurate protection assessment.
Purpose of the Study:
- To compare five different methods for quantifying the UVA protection factor (UVA-PF) of commercial sunscreens.
- To identify the most suitable sunscreen based on its UVA protection capabilities.
Main Methods:
- Two clinical methods on human skin: UVA-induced tanning inhibition and methoxsalen plus UVA-induced phototoxicity inhibition.
- One animal method: UVA-induced sunburn cell production in mice treated with methoxsalen.
- Two in vitro methods: solution-dilution and sandwich spectrophotometry.
Main Results:
- All five methods provided a quantitative estimation of UVA protection.
- The calculated UVA protection factor varied depending on the specific method employed and the time of measurement.
Conclusions:
- While multiple methods can estimate UVA protection, no single method is currently accepted as a definitive standard.
- Further research is needed to establish a standardized, reliable method for determining sunscreen UVA protection.