Applying SPF 30+ protects you from 97% of UV rays, while SPF 50+ from 98%. This means that some rays will still reach your skin despite wearing sunscreen, so it will not prevent tanning completely. You will still be able to get some colour on your skin, just at a slower, more manageable rate, whilst lowering the risks of damaging your skin.
This does, however, mean that you are able to burn. With SPF 30, it will take roughly 30 times longer to burn than if you leave yourself unprotected in the sun, assuming it is correctly applied. So ensure that you reapply sunscreen to limit the damage to your skin.
When choosing a sunscreen, there are two types that help defend the skin against UV damage:
- Chemical-based sunscreen absorbs UV rays and alters them before they penetrate the skin and cause damage.
- Physical-based sunscreen reflects the rays away from your skin. As explained above, no sun cream is 100% effective against protecting your skin so you can tan with sunscreen.
1Ramos-e-Silva et al., ‘Anti-aging cosmetics: Facts and controversies’. Clin Dermatol. 2013 Nov-Dec; 31(6): 750-