Sunscreen

 
Organic (chemical) filters 
 		 Inorganic (mineral) filters
 Substances
  • avobenzone, octocrylene, octinoxate, oxybenzone, octisalate, homosalate
  • titanium dioxide, zinc oxide
     
 Effect
  • absorption of UV radiation
     
  • absorption of UV radiation
  • reflection (< 5% of the UV range (5))
 Application
  • regularly (every two hours)  
  • adequate amount (2 mg/ cm² of skin, i.e. 35 g of cream for the whole body for an adult of standard height and weight)
  • regularly (every two hours)  
  • amount (2 mg/ cm² of skin, i.e. 35 g of cream for the whole body for an adult of standard height and weight) 
 Skin   penetration
  • penetrate epidermis and are systemically absorbed (20)
     
  • minimal if any penetration of the skin (22, 23) 
     
 Possible side   effects
  • allergic / irritant contact dermatitis 
  • phototoxic/ photoallergic contact dermatitis
  • contact urticaria
  • no relevant skin-irritating properties or sensitization potential (3)
  • reflection of visible light (> 400 nm) can cause whitening effect
 Use for
  • teenagers and adults
     
  • babies and children
  • sensitive skin

 

References

 

(3) Lau­tenschlager et al. 2007 - Adverse Reactions to Sunscreens
(5) Cole et al 2015 - Metal oxide sunscreens protect skin by absorption, not by reflection or scattering
(20) Matta et al 2020 -  Effect of Sunscreen Application on Plasma Concentration of Sunscreen Active Ingredients
(22) Gulson et al. 2012 - Comparison of dermal absorption of zinc from different sunscreen formulations and differing UV exposure based on stable isotope tracing
(23) Sadrieh et al. 2010 - Lack of significant dermal penetration of titanium dioxide from sunscreen formulations containing nano- and submicron-size TiO2 particles