In a nutshell:
- UVB causes the burning, UVA causes the cancer (this was based on what I read but a reader has since sought a correction, see the link https://www.skincancer.org/prevention/uva-and-uvb
- Factor 30 blocks 97% of harmful UVB but Factor 50 blocks 98%
- All good suncream has a UVA star rating from 1-5. The star rating shows you how much UVA it’s blocking relative to how much UVB. So a factor 50 with a two star rating is less effective against the sun’s danger than a 20 factor with 5 stars.
- Very often its the cheaper own brand creams that have the better star rating. Check out the below examples of Tesco and Ambre Solaire. Word is that Morrisons and Wilkos own creams are all 5 star. The Ambre Solaire was £10 while Tesco's own brand was only £3 pounds.