SPF 30 is an essential pack in holiday cases to protect from the sun. But might you be better off with a much higher protection factor?
The addition of SPF 100 to chemists and beauty aisles might suggest so.
As a reminder, SPF translates to sun protection factor, with the number describing how well it blocks out UVB rays.
‘UVB can penetrate the highest levels of skin causing burning, peeling and blistering,’ says consultant dermatologist Dr Mary Sommerlad.
‘It is associated with non-melanoma skin cancers and pre-cancer changes known as actinic or solar keratoses.’
The number relating to your SPF correlates to the time you’re able to spend in the sun without burning compared to how long you could spend in the sun with the SPF.
Dr Ross Perry, a dermatologist and skin cancer expert and founder of Cosmedics, says that you can multiply the SPF factor by the speed of burn.
‘If you would burn after 15 minutes in the sun without protection, an SPF 30 would give you 30 times that protection – so around four to five hours in the sun without burning,’ he says.
How long does SPF 100 last then?
‘SPF 100 generally just means that it would give 100 times the protection of what a normal burn time would be,’ Dr Perry explains to Metro.co.uk.
Meaning, SPF 100 would protect someone who would burn in 15 minutes for 1,500 minutes, which is over 24 hours.
It’s not an exact science as it’s hard to work out exactly how long it would take you to burn.
‘Everyone is individual; one person may burn after 10 minutes while another may burn after 20 minutes, so one person may need to reapply after two hours while another needs to reapply after three,’ notes Dr Sommerlad.
And human error is a big player in suncream effectiveness. ‘It is never the case that coverage will last exactly 100, 50 or 30 times the burn times as people sweat, wash SPF off in pools or the sea, or rub it off against clothing,’ says Dr Perry, all of which reduces the effectiveness of suncream.
So, does SPF 100 work?
The research backs the use of SPF 100 over lighter coverage. For instance, a 2018 study that involved 200 participants wearing either SPF 50 or SPF 100 before six hours of sun exposure found that 55% of the SPF 50+ wearers had signs of sunburn, compared to just 5% of SPF 100+ users.
Similarly, research from 2020 reported that 56% of people who applied SPF 50+ every day for five days had sunburn, compared to 7% who wore SPF 100+.
However, Dr Perry notes that it’s unlikely a suncream will protect you for the full time suggested by the SPF. ‘For that reason, we normally recommend reapplying every two-to-three hours if you’re in a sunny, hot climate – even if you’re using a high SPF,’ he says.
The exact reason why higher SPFs protect you for longer is down to increases in effectiveness at blocking UVB rays, says Dr Perry.
‘SPF 100 is normally about 99% efficacious in terms of its sunblock, whereas SPF 50 is 98% and SPF 30 is 97%,’ he explains. ‘As you can see, there is not a great deal of difference between them.’
Dr Sommerlad adds: ‘Very pragmatically, SPF 100 lets in less UVB than traditional SPFs so if you are prone to burning, the more protection the better. However, 1% of UVB still will get through and in intense sunlight this can still be enough to lead to sun damage to the skin.’
What to look for in a suncream
SPF refers to the protection from UVB rays, but Dr Sommerlad says there are other aspects of the sun to protect from.
‘As well as SPF, it is important to consider other factors in your sunscreen such as UVA protection,’ she says. ‘UVA rays can contribute to premature ageing and skin cancer including melanoma.’
UVA protection is shown on suncream bottles as a star rating. According to the NHS, you can see a star rating of up to five stars on UK sunscreens. The higher the star rating, the better the protection.
‘You should also consider your skin type and the ease of application,’ says Dr Sommerlad.
A suncream that is to your preference and sits comfortably on your skin will also ensure you keep topping up throughout the day.
For those after a SPF 100, she recommends Heliocare 360 MD SPF 100 Fluid which also contains anti-oxidants. ‘These can help reduce damage from sun and pollution,’ she says.
‘Remember that sunscreen is only one factor in protection from sunburn. Physical protection is just as important, so avoid sunbathing, wear a hat, sit in the shade and wear UV protective clothing.’
Is SPF 100 worth it?
Whether or not you hunt down SPF 100 depends on your needs.
SPF 100 does not mean total protection from the sun, and given how much harder it is to find than lower SPFs, such as 50 or 30, Dr Perry says it might be better to wear a lower protection and be religious about reapplication.
Regularly topping up your protection will also be easier with lower SPFs as, in order to be a tiny bit more effective, SPF 100 formulas can often be thick and claggy.
‘People often find it too uncomfortable, thick or greasy to wear,’ he says.
However, Dr Sommerlad believes SPF 100 can be a good extra dose of protection. ‘In my experience, SPF 100 is geared towards those prone to sunburns and those with a history of pre-malignant and malignant skin changes.
‘It’s also a good one to consider for those in intense sunlight (such as someone hiking all day in the summer). There is no harm in people using an SPF 100 at anytime but, as with any sunscreen, reapply after sweating, swimming and towelling off.
‘I also recommend following the instructions on the sunscreen’s labelling as it will gradually wear off through the day. Certainly reapply every two hours if you are spending time outside and are prone to sunburns.’
Maybe just like all healthy habits, we’re better off with consistent suncream habits, rather than intense and irregular ones.
Do you have a story to share?
Get in touch by emailing [email protected].
MORE : UK to swelter in temperatures of up to 31C today as heatwave moves in
MORE : How to sleep in hot weather – 9 tips amid July 2024 heatwave
MORE : M&S shoppers rush to get hands on best-selling dress that ‘doesn’t crease’ and perfect for holidays
Sign up to our guide to what’s on in London, trusted reviews, brilliant offers and competitions. London’s best bits in your inbox
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.