Do You Need To Apply 'Once A Day' Sunscreen More Than Once A Day? This Study Says Yes

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With summer time right around the corner, most of us are becoming more and more aware about SPF use, whether we're off on holiday or just staying in the UK. While, as a beauty writer, I would 100 percent recommend wearing SPF on your face all-year round (I opt for SPF 50), the warmer months of course are most important when it comes to sun protection. But how often should you apply SPF on your face and body? And do you need to apply 'once a day' sunscreen more than once?

Well, in a nutshell, the answer is pretty much yes. Research conducted by Which? showed that applying a sun screen (even one that says it only needs to be applied once daily) only once is not sufficient. It tested four sunscreens that claimed they only needed to be applied once daily, and found that, after six to eight hours, the average Sun Protection Factor (SPF) offered decreased by 74 percent.

Despite this, some manufacturers of the brands used rejected the claim, and said their own testing had shown different results. The products used were: Soltan Once Invisible 8hr Sun Protection (SPF 30) 200ml, Piz Buin 1 Day Long Lotion (SPF 30) 150ml, Riemann P20 Once a Day Sun Protection (SPF 30) 200ml, and the Ultrasun Family (SPF 30) 100ml.

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So who should we believe? Despite facing criticism and reservations about their research, the research Which? conducted does sound plausible, especially when considering the amount of times we may go swimming on holiday, rub off product, and sweat during the day.

Advice from experts at the Skin Cancer Foundation also states that sun cream should be reapplied around every two hours. "Reapplication of sunscreen is just as important as putting it on in the first place, so reapply the same amount every two hours," the website states, adding: "Sunscreens should also be reapplied immediately after swimming, toweling off, or sweating a great deal."

The NHS also points out that the timing of SPF application is also rather important. They advise applying sunscreen 30 minutes before going out, and just before sun exposure. This is especially crucial if you are going to be exposed to the sun for a longer period of time. The NHS also states that sunscreen "needs to be reapplied liberally and frequently," suggesting once (no matter the formulation), is probably not going to be enough. This even applies to "water resistant" formulations, apparently.

So what product should you be applying? I have a number of formulas I tend to rely on for my face, including the Kiehl's Ultra Light Daily UV Defense (it also comes in a new lightweight formula that's practically undetectable on skin), and the Ren Clean Screen Mineral SPF 30, which is lovely on the skin and isn't damaging for the environment. When it comes to body, I really like the SPFs by Avene and La Roche Posay, both of which are brands that are available at your local Boots, are affordable, and are suitable for even the most sensitive skin types.

Happy SPF season!