• Prevents UV radiation reaching the skin
  • UVB (ultraviolet radiation) causes sunburn (and also enables vitamin D production)
  • UVA causes wrinkles, brown spots (photoageing)
  • Both UVB and UVA can contribute to the development of skin cancer

SPF = Sun Protection Factor (the number of times longer you can stay in the sun before burning compared to wearing no sunscreen) indicates UVB protection

The amount of UVB radiation that is filtered out varies with different SPFs:

  • SPF 15 blocks 93% of UVB;
  • SPF 30 blocks 96.7% of UVB;
  • SPF 50 blocks 98.3% of UVB.