After the blazing weekend sunshine, lobster-coloured sun-worshippers around the country will be slathering themselves in moisturiser and wishing they'd worn a suncream with a higher factor. If they wore any at all, that is. Could factor 100 – the latest super-high SPF product to appear in the US – not only have spared the sunburn, but be a panacea for all sun-related ills, from heat rashes and redness to photo-ageing and skin cancer, now at a record high, according to reports last week? Alongside Neutrogena's Ultra Sheer Dry Touch Sunblock with SPF100, another American company, Banana Boat, has introduced a pair of SPF 85 sprays. Will super-high-factor creams be coming to Britain soon, and if so, do we actually need them?
Firstly, there would have to be a change in the EU's recommendations, which effectively restrict labelling of suncare products to no higher than an SPF of 50. Secondly, while higher factors offer better protection than lower ones, there are other issues that influence the effectiveness of suncream that anxiety-inducingly high numbers distract from. "The question of whether seriously high SPFs are worth using is a tricky one," says Mike Brown, suncare scientific adviser for Boots. "What always worries me about these things is losing sight of the technology and the performance, and these products becoming a commercial numbers race along the lines of, 'my number is bigger than your number'. There will be a point at which that becomes ridiculous, but it's hard to say where that point is." Ed Yong, health information manager at Cancer Research UK, says, "there is absolutely no need to go remotely as high as factor 100. We recommend people choose a factor 15."
So what exactly does factor 15 mean? The SPF refers to the amount by which natural burning time is extended by blocking out shorter wave UVB rays – the primary cause of sunburn. Factor 15 technically enables the wearer to stay out in the sun 15 times longer than they would without any sun protection. In reality, however, the amount of time someone can spend in the sun before they start to burn varies depending on how fair or dark they are, and how much sun exposure they have had in the past, while the protection stated on the bottle is only accurate if we apply enough cream.
"We know that a lot of people don't apply suncream as thickly as they should," says Dr Yong, "and if you only apply a thin layer you are getting a very small amount of protection, regardless of the factor that you use. People need to apply around two tablespoons to cover their entire body if they are wearing a swimsuit or about two teaspoons to cover their face, arms and hands. Most people apply about a quarter of that." Dr Sarkany, consultant dermatologist at St John's Institute of Dermatology, Guys and St Thomas' NHS Foundation Trust says, "people tend to wear suncream two-thirds less thickly than they should. A higher factor, say 35 or more, will ensure that the real factor is enough." He also emphasises that sunscreen is only useful if you don't use it as an excuse to stay out in the sun longer than you should. Sitting in the shade and covering up with clothing are safer than relying on cream.
Dermatologists differ in their recommendations of which factor to wear. There's also the added complication that avoiding any sun exposure at all can be bad for your health, as lack of vitamin D, which is a product of sun exposure, has been linked to problems such as osteoporosis, MS and breast cancer. Ed Yong recommends 10 to 15 minutes a day of "casual exposure". For sun protection, Yong recommends factor 15, which offers 93 per cent protection from UVB, compared to 97 per cent at factor 30.
This sounds like a minimal difference, but Mike Brown at Boots sees it differently. He explains that it's not the UV rays that are being blocked that count, but the ones that get through. So the two per cent difference between 25, which blocks 96 per cent of UVB rays, and 50 which blocks 98 per cent, might sound insignificant, but if you imagine it as the difference between an alcoholic drink with two per cent alcohol or one with four per cent alcohol, then suddenly the percentage difference doesn't seem so small. However, the higher you go, the less the difference, so SPF 100 blocks 99 per cent of UVB rays, while 50 blocks 98 per cent.
The other key label to look for in suncream is the UVA protection. UVA rays penetrate deep into the skin and play a big role in ageing, and many sun creams now carry a star rating system to indicate how well the product protects against it. Five-star products have to protect against 90 per cent of UVA, four against 80 per cent and three stars against 60 per cent. According to Mike Brown, "one- and two-star are a waste of time."
As Brown points out, attitudes towards tanning are changing as companies such as Boots recognise that telling people not to tan at all is a lost cause. "For a long time we were saying that you shouldn't get a tan because its not good for you, but then we realised we were banging our heads against a brick wall. Now we are saying if you are going to get a tan, this is how do to it as safely as possible."
Within the beauty and fashion industries – which bear some responsibility for perpetuating the idea of tans as desirable – the knowledge that UV light can be damaging hasn't eliminated images of bronzed bodies. Ultra-pale skin is seen as more desirable than it used to be, but a flick through a summer issue of most fashion magazines reveals plenty of tanned flesh, and at last month's Met ball the likes of Kate Moss and Victoria Beckham had deep 1970s-style tans. These images make it hard to remember that any tan at all is a sign of skin damage, but choosing a reliable suncream should be part of everyone's personal take on the Government's new heatwave plan.