title: Suntanning with sunscreens: a comparison with sunbed tanning.
abstract: OBJECTIVE
  Acquiring a tanned skin, either by sunbathing, sunbed use, or a combination of both, is a desirable objective for many people. The objective here was to compare the ultraviolet (UV) exposure resulting from a 2-week vacation spent sunbathing with sunscreen-protected skin, with that from a typical course of 10 sessions on a sunbed.
  
  
  METHODS
  A numerical analysis combining data on sunlight and sunbed UV levels, time spent tanning and spectral absorption properties of different types of sunscreen.
  
  
  RESULTS
  The analysis showed that unless a sunscreen provides optimal broad-spectrum protection, a 2-week sunbathing vacation that avoids sunburn on sunscreen-protected skin can result in a higher cumulative UV exposure than a typical 10-session sunbed course. The lowest exposures for a given sun protection factor (SPF) are obtained when sunscreen delivers broad-spectrum protection that approaches the ideal of uniform absorption at all wavelengths throughout the UV spectrum.
  
  
  CONCLUSIONS
  In extreme cases of recreational sun exposure where sunscreens providing suboptimal broad-spectrum protection are used, the UV insult to the skin is likely to result in higher cumulative exposures than commonly employed sunbed practices.
authors.affiliation: Dermatological Sciences, Institute of Cellular Medicine, University of Newcastle, Newcastle, UK.
authors.forename: Brian L
authors.initials: BL
authors.lastname: Diffey
authors.affiliation: BASF PCN GmbH, Monheim, Germany.
authors.forename: Uli
authors.identifier: http://orcid.org/0000-0003-2988-3428
authors.initials: U
authors.lastname: Osterwalder
authors.affiliation: BASF Grenzach GmbH, Grenzach-Wyhlen, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Herzog
mesh_terms: D004781:Environmental Exposure / Q000032:analysis*; D006801:Humans; D011829:Radiation Dosage; D012867:Skin / Q000528:radiation effects; D059405:Sun Protection Factor; D055108:Sunbathing; D013473:Sunscreening Agents / Q000008:administration & dosage*; D014466:Ultraviolet Rays
chemical_list: D013473:Sunscreening Agents
keywords: UV exposure; broad-spectrum; sunbed; sunscreen