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Celebrities and A-list skincare experts swear you should be using SPF 100 for the best skin

You’ll be slathering it on in no time.

11 Aug 2019

Much to everyone's surprise, the sunshine is making a long-awaited appearance and the question of which SPF to choose is on our minds.

Sun cream has risen in popularity and effectiveness over the past year, and it seems the higher the protection factor, the better. In a 2018 study conducted at Kings College London, they found that most people underestimate the level of SPF they need. “Given that most people don't use sunscreens as tested as tested by manufacturers, it's better for people to use a much higher SPF than they think is necessary” says Report Author, Professor Anthony Young.

We’re accustomed to the likes of SP15 and its older sibling, SPF50, but we might have found something even better: SPF100.

Nicole Kidman swears by the stuff, telling Allure: "I'm outside a lot and love exercising outdoors, but I don't like the sun on my skin because it's very fair. My parents have also had skin cancer, so I have to be really, really careful — I use the SPF 100. I know it sounds like a lot, but it isn't. I use it on my kids. I use it on myself. I've always had to do that."

It’s an intimidating amount, almost unbelievable, and with such a drastic numerical increase comes speculation as to whether this actually works and if the hype surrounding this is justified. We spoke to the experts to get their take on SPF100 and whether it actually makes a difference.

What’s the difference between SPF100 and other SPFs?

“The overall difference in UVB protection between an SPF 100 and SPF 50 is really marginal and confusing for consumers as they seem to think it offers double the protection which is in fact not true. Properly applied SPF 50 sunscreen blocks 98 percent of UVB rays. When used correctly, sunscreen with SPF values in the range of 30 to 50 will offer adequate sunburn protection, even for people with pale skin and this should still be applied frequently,” says Dr Ross Perry, Medical Director of CosmeducsUK who has a special interest in dermatology.

How many UVB rays does SPF100 allow through?

“SPF15 lets about 7% of UVB rays, SPF30 lets around 3% through, and SPF50 about 2%. As for SPF100, this high sun protection factor allows around just 1% of UVB rays through. Now, although SPF100 sounds impressive, it is actually impossible to obtain technically – this is why the US forbids it to be advertised,” says Dr Tina Meder, a dermatologist, cardiologist, and founder of Meder Beauty Science.

How often should you reapply SPF100?

“Normally, the higher the number means you can stay outside for longer, so in this case, it would be highly unusual for someone to be able to stay out in the sun longer than what a factor 50 SPF would protect against. Additionally, when comparing SPF 100 to others, you will often find the instructions will advise to reapply just as often as an SPF 30 sunblock,” says Dr Daron Seukeran, Group Medical Director for the UK’s leading skincare clinic group, sk:n.

Does having a high SPF affect our Vitamin D absorption?

“Yes, realistically we do need a certain amount of sunlight in order to produce vitamin D and there have been concerns around patients using high factor sunblock and becoming vitamin D deficient.” says Dr Daron Seukeran.

Read our comprehensive guide on sun care creams to use this summer.