SPF: what is it & how does it protect the skin?

‘Remember to use SPF!‘ – it’s a commonly used phrase, but what does SPF mean? Here’s everything you need to know…

What is SPF?

SPF stands for Sun Protection Factor, and the number that follows suggests how long a suncream or product is likely to protect the skin from the sun’s ultraviolet B (UVB) rays. For example, using SPF 50 allows you to spend more time in the sun before burning compared to SPF 15.

While also dependent on other factors such as skin type, the time of day and location, it’s used as a measurement of protection against the sun.

UVA and UVB rays – what’s the difference?

Ultraviolet A and B rays both come from sunlight, but affect the skin differently. According to the Cosmetics, Toiletry and Perfumery Association’s (CTPA) Sun Protection Campaign 2025, the overexposure of UVB rays damage cells in the outer skin layer, leading to redness and sunburn. UVA rays, on the other hand, can penetrate deeper into the skin’s tissues and are more responsible for signs of skin ageing.

While SPF numbers communicate protection against UVB, to ensure UVA protection, look for products that feature the letters UVA in a circle on the packaging.

How often should SPF be applied?

It is recommended to apply SPF every two hours, or immediately after your skin comes into contact with water. Apply 15 to 20 minutes before sun exposure to allow it to absorb properly.

UV safety in the beauty industry

The UV Safety Initiative, launched by the British Beauty Council, aims to boost industry knowledge around suncare, SPF and the risks of UV radiation. This year-long campaign will pave the way for the formation of the British Beauty Council UV Safety Coalition.

Brands including LOOKFANTASTIC, Debenhams, Boots, No7 Beauty Company and L’Oréal Groupe are supporting the initiative to help spread awareness.

The campaign follows the launch of the All-Party Parliamentary Group (APPG) for Beauty & Wellbeing’s first inquiry into UV safety. On 21 May 2025, MPs, beauty professionals and business leaders gathered to hear the group’s intentions to increase consumer protection from UV damage. The inquiry will provide UV safety recommendations to the UK government, and plans to release its findings in spring 2026.

Skincare expert & brand founder, Caroline Hirons, speaking at the launch of the APPG inquiry.