What does SPF mean?
All sunscreens in the UK are labelled with the letters SPF. SPF stands for sun protection factor. The SPF number is determined in lab tests by exposing skin to a light spectrum that mimics the level of UV at midday. The SPF is the level of protection that is offered against UVB (it’s the measure of time that you can stay in the sun with sunscreen on before redness occurs on the skin). So if you are a person who would start to burn after about 10 minutes in the sun without sunscreen then by applying an SPF 15 (10 minutes till burn time x 15 spf = 150) you would gain 150 minutes of UVB protection.
UVA & Star System
On sunscreens purchased in the UK you will find the UVA logo (“UVA” printed in a circle) accompanied by up to 5 stars.The UVA logo indicates that the UVA protection is at least a 1/3 of that of the SPF.The stars indicate the amount of UVA rays absorbed by the sunscreen in comparison to the UVB. So if you purchase a sunscreen with a low SPF, it might have a high star rating but that doesn’t mean its got super powerful UVA protection it just means that the correlation of UVA & UVB protection is about the same. So to ensure that your skin is getting the best protection opt for a sunscreen that has both a high SPF and high UVA star rating, these are the sunscreens that are referred to as “broad spectrum”.SPF in MoisturizersThough they are tested in exactly the same way as regular sunscreens, they are less likely to give you the same level of protection. They tend to be thinner formulations and don’t last on the skin as long as a separate sunscreen. Though they are perfectly adequate for limited exposure to the UV that you will encounter in your daily routine but for exposure time of over an hour you are better off with a separate sunscreen.
Organic & Inorganic Filters
If you only buy one single skincare product PLEASE make it sunscreen. Unfortunately buying sunscreen can be both confusing and frustrating, so lets go through the basics of sunscreen.
How Do Sunscreens Actually Work?
Sunscreens are available in two types Organic and Inorganic filters.
Organic Filters (also known as Chemical Filters)
Don’t think that “Organic” means lovely, all natural ingredients organically grown; I’m afraid its just the scientific term for this type of sunscreen. Organic Filters work by actually absorbing UV radiation, converting it to heat and then allowing it to disperse “harmlessly“. Organic Filters tend to absorb more UVB than UVA rays. Organic Filters are absorbed by the skin and secreted in the urine. Dermatologists advise that this type of sunscreen should not be used by women who are pregnant or breastfeeding and should NOT be used on children.
Inorganic Filters (also known as Physical Sunscreens)
Inorganic Filters protect the skin by providing a physical block against UV rays. They tend to be opaque and have a thicker consistency (but they are getting lighter and better!). I prefer Inorganic Filters as they are not absorbed by the skin and at the end of the day can be simple cleansed away. They are also more suited to sensitive skin as they rarely cause any problems. Think of Inorganic Filters working like a mirror on your skin reflecting away those nasty UV rays. There is a great debate about Organic V Inorganic Filters, more of which later.