How does SPF work?
SPF stands for Sun Protection Factor. It is a measure of how long the sunscreen offers UVB protection as well as the amount of UV radiation that it is able to defend against. For instance, an SPF of 15 offers longer and more protection than an SPF of 6.
Whilst the extent to which an SPF can offer protection against sun rays (or how ‘well’ the SPF can defend against sun damage) only varies marginally between different SPF’s – generally defending against between 97% and 99% of UV radiation, the amount of time you can spend in the sun before getting burnt is directly proportional to the SPF value you apply.
In other words, a sunscreen with an SPF of 15 will allow you to stay in the sun 15 times longer without burning, compared to how long you could have stayed outside without burning if you were not wearing sunscreen. On the other hand, an SPF of 6 will only allow you to stay in the sun 6 times longer.
To be on the safe side, it is recommended that you reapply a sunscreen every couple of hours and that you try to wear protective apparel (such as a hat or long sleeves) when spending extended time in the sun.
The reason that we decided to include an SPF of 15 in our day moisturisers is because most people spend the majority of their time indoors (at work), and an SPF of higher than 15 is, generally, not necessary. For additional care, our SPF 30 Light Advanced Expert Serum can be applied after moisturising.