13 myths about sunscreen you need to know - and the most common skin cancer hotspots on your body, revealed by dermatologists

Daily Mail​

4 hours ago

You might think you know everything there is to know about sunscreen – just slap it on when the sun's out, right? – but a chat with a proper skin expert would probably reveal otherwise.
From the areas that often get missed (and can therefore be skin cancer hotspots) to the efficacy of moisturisers and foundations that have 'SPF' emblazoned on them versus traditional sunscreens, there's a lot to unpack when it comes to keeping your skin safe against UVA and UVB rays.
That's why we spoke to Dr Justine Kluk, consultant dermatologist who writes the Skin Confidence newsletter, and Skin + Me 's head of medical Dr Jason Thompson, to sort the myth from the fact when it comes to sun protection.
MYTH: You can't get sunburn underwater
Does being in the swimming pool keep you safe from the sun's rays? Unfortunately, the answer is no. 'You do need sunscreen in the pool' confirms Dr Kluk. 'UV radiation can penetrate below the surface of the water. So if you're swimming or even just standing waist-deep chatting, your skin is still exposed. Water also reflects sunlight, which can intensify UV exposure on any bits of your body above the surface (such as your shoulders, face and back).'
MYTH: Expiry dates are just a guide
There are some skincare and make-up items where you can take the expiry date with a pinch of salt, but sunscreen is definitely not one of them, says Dr Thompson. 'Sunscreen is the one product that really does need to be in date, given its role in protecting your skin from UV rays, which cause skin cancer and premature ageing,' he says. To find out how long your sun cream lasts 'look for a symbol on the bottle showing an open pot with a number, for example 6M, which means it is good for six months after opening. After this period you cannot be sure whether the product will remain effective.'
If you're not sure how long the product has been open – which is often the case when we dig out the sunscreen each summer – then don't just hope for the best. 'Given how important sunscreen is, it is not worth the risk' says Thompson. 'If you are unsure, buy a new one.' Changes in smell and texture, or separation of the product, are strong signs that it has gone off.
MYTH: A few episodes of sunburn don't matter
People of a certain age might remember being told that a sunburn is a good thing, because once it's no longer red you go brown! Well guess what – the dermatologists certainly do not agree with this point. 'Studies show that just five sunburns can lead to a doubling in the risk of developing melanoma, the deadliest skin cancer' points out Thompson. If you have kids, you need to be extra conscientious, because 'In children up to the age of 15, a study published earlier this year found that every blistering sunburn episode results in a 3% increased risk of developing melanoma later in life.' If it's hard to get your kids out of the swimming pool or sun, then SPF 50 rash vests as well as sunscreen are a good idea, says Dr Kluk.
MYTH: You can't burn when it's cold
According to Thompson, people frequently get burnt when they are skiing, because 'snow reflects UV rays, increasing the dose your skin receives.'
MYTH: Most people apply sunscreen correctly
Quite simply, the majority of people are not applying enough sunscreen, and we're not applying it regularly enough. 'To get the labelled SPF, sunscreen must be applied at a thickness of 2mg per square centimetre of skin,' says Thompson. 'Studies show people often apply only one third to half this amount. This does not just halve the protection; it reduces it much more than that.' As an easy-to-follow guide, Kluk says 'for an adult, you need about a quarter of a teaspoon of sunscreen for the face, neck and ears, and six to eight teaspoons for the body if you're not covered up'.
Not reapplying is also a common issue that can lead to sunburn. 'Sunscreen should be reapplied every two hours when outdoors, and more frequently after swimming, sweating or towelling off,' says Kluk.
MYTH: You can tan completely safely
Some people tan very easily, which may lead you to believe that there's no long-term implications to doing so. Although the impact varies according to your skin type, Kluk says it is 'not really' possible to tan safely. 'A tan is your skin's way of trying to protect itself, and means UV damage has already occurred,' she says. 'Some people burn more easily, others tan more easily, but both are forms of sun damage.'
Thompson adds 'For people with fair skin, lots of moles or a history of skin cancer, tanning may significantly raise their risk of skin cancer and photo-ageing. For those with darker skin tones who rarely burn, the cancer risk is lower, but repeated exposure can still lead to premature ageing and worsening of hyperpigmentation disorders like melasma.'
MYTH: Sunscreen needs to absorb before working
Most of us have heard the rule about applying sunscreen before you go out, but the actual reason behind it might not be that widely known. 'The British Association of Dermatologists recommends applying sunscreen 10 to 15 minutes before going outdoors, and then again shortly after' explains Thompson. 'This is not because sunscreen needs to absorb before working (that's a myth) but because a second application helps cover areas you may have missed the first time round'. Common areas that people miss include the ears, top of the scalp, lips, eyelids and tops of the feet. 'These are all sites where skin cancers often develop' reveals Thompson.
MYTH: When it's cloudy you don't need to worry about sun protection
'Cloud cover does not reliably block UV, and in some cases can scatter rays and increase your exposure' reveals Thompson. A more reliable way to know if you need sun protection than simply looking at the sky is to check the UV index that day. 'If it is 3 or above, sun protection is recommended.'
MYTH: SPF make-up alone is fine
According to Thompson 'SPF is now being incorporated into a wide range of products, including make-up, moisturisers, mists and setting sprays. This is generally a good thing, as these products can provide an extra layer of protection.' However, he says they should be 'seen as an additional support' with 'a good quality cream or lotion sunscreen used as the main form of protection.' He adds that 'moisturisers with SPF will often not offer broad spectrum protection [against both UVA and UVB rays] as they are not categorised as dedicated sunscreen products', and therefore don't have to adhere to the same rules. Sunscreen should be reapplied to the face every two hours – if this is impractical once you've got make-up on, then a spray or stick sunscreen can work too.
MYTH: A spray sunscreen will give you the best coverage
Spray-on sunscreens have become increasingly popular in recent years, perhaps because it feels that by hosing yourself down with the stuff you're getting the ultimate level of coverage. It is true that all sunscreen formats are effective when applied correctly, but the problem of 'under-dosing' (i.e. not applying enough) is more prevalent with spray and stick formats because 'there's very little help or advice out there to guide people on the amount' says Thompson. A cream or lotion may be your best best if you want to make sure you're getting the right amount.
MYTH: Sunscreen can stop you getting moles
While freckles and sun spots are a response to UV, and can be prevented by regular and correct use of sunscreen, moles are 'largely genetic' explains Thompson. However, while UV exposure might not cause them to form, it can cause changes to existing moles.
MYTH: Sunscreen is the most effective way to protect your skin
'It's important to remember that no sunscreen product will block 100% of the UV rays' says Thompson. 'Physical protection such as hats, sunglasses and clothing remains important, and actually more effective than sunscreen.' Kluk agrees, recommending that we 'avoid direct sunlight between 11am and 3pm' and 'opt for UV protective clothing where you can.'
MYTH: All sun exposure is bad
In case all these warnings have left you thinking you should simply never leave the house again, it's worth noting that 'sunlight does have health benefits', according to Thompson. 'It helps us produce vitamin D, can support cardiovascular health by releasing nitric oxide in the skin, and has a positive impact on mental wellbeing.'
As with most things, moderation is key. 'The most important universal message is to avoid burning,' says Thompson.