title: Measurement of sunscreen UVA protection: an unsensitized human model.
abstract: BACKGROUND
  Concerns have recently been raised regarding protection provided by sunscreens in the UVA spectrum. No standard testing protocol exists for quantifying this protection.
  
  
  OBJECTIVE
  These studies were conducted to investigate the components of an ideal test methodology to quantify the UVA protection provided by a sunscreen.
  
  
  METHODS
  Sunscreen products were tested on unsensitized human subjects with UVA from a xenon arc lamp in a protocol similar to the sun protection factor test. The biologic end point was either minimal erythema or tanning 24 hours after UVA exposure.
  
  
  RESULTS
  The UVA protection factors ranged from 2.1 to 6.9 depending on the type of absorber and the UVB blocking filter, but not on the irradiance of the source or the type of response (erythema or tanning).
  
  
  CONCLUSIONS
  This test method provides a realistic in vivo estimate of the amount of UVA protection provided by sunscreens.
authors.affiliation: Johnson & Johnson Consumer Products Inc., Skillman, NJ 08558.
authors.forename: C
authors.initials: C
authors.lastname: Cole
authors.forename: R
authors.initials: R
authors.lastname: VanFossen
mesh_terms: D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008297:Male; D013473:Sunscreening Agents / Q000627:therapeutic use*; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D013473:Sunscreening Agents