What No One Bothered To Tell You About Sunscreen

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You don’t get anything for free in this world and even as pure a joy as a sunny day has its downsides. There’s no point complaining about it – regularly applying sunscreen is just the price you have to pay for enjoying the sunshine. The alternative is short-term pain in the form of sunburn and potentially long-term disaster in skin cancer.

Here’s everything you need to know about sunscreen.

Will sunscreen stop me getting a tan?

Well, tanning is an indication of damage to the skin, but if you want a little colour to show for your two weeks on the beach, rest assured you can achieve this without risking the sunburn.

“Although sun cream creates a protective barrier, it will not always stop the tanning process completely,” says Dr Paul Stillman, a GP and advisor to Soleve Sunburn Relief.

“Avoid burning by using a minimum SPF 30 sun cream and being sensible in the sun by making the most of cover and avoiding peak times. You’ll still be able to get bronzed, but you will be better protected.”

Will a base tan protect me?

Spending a few days on a sunbed before heading on your holidays does not remove the need for you to pack sun cream.

“A base tan will not reduce your risk of sunburn and doesn’t act as a form of protection,” says Stillman.

“Experts estimate that going out in the sun with a base tan is equivalent to wearing a sunscreen with a very low SPF of 3 to 4. To better protect yourself, you should still use a high SPF sun cream of 30+.”

OK, how much lotion should I use?

About 30 grams – roughly equivalent to a shot-glass full. For the face and neck you should be using about one-quarter of a teaspoon amount at each side.

How often should I apply sunscreen?

At least half an hour before going out – it takes time for sunscreen to bind to the surface skin layers and become effective.

Does waterproof lotion last longer?

Although some sunscreens say they are waterproof, sunscreen can still be sweated off – so reapply at least every two hours.

Exactly two?

Try not to leave it any longer than that. There are Android and iOS apps that alert you when you need to top-up your tanning lotion.

This one says it’s “once a day”

Be wary. A study by consumer watchdog Which? found that four major high-street sunscreen brands lost their sun protection factor (SPF) by 74% after six to eight hours.

What do SPF numbers mean?

SPF stands for Sun Protection Factor and relates to the protection offered against UVB rays, the kind that cause sunburn. The numbers indicate how long the sunscreen should protect you from sunburn. So if your skin would normally burn after ten minutes in the sun when unprotected, in theory factor 30 sunscreen should protect for 30 times as long – 300 minutes or five hours. Higher SPF numbers do also mean more protection in general but it’s not a linear scale – factor 30 is not exactly twice as strong as factor 15. Factor 30 keeps out around 97% of UVB rays and factor 15 around 93%, while opting for factor 50 will block 98%.

However, in practice, no-one applies sunscreen in the comprehensive way it is done when testing the product and it can be sweated or washed off, so you have to reapply every couple of hours to be safe regardless of the SPF rating. This is why opting for a higher rating is sensible, as you probably won’t be getting the level of protection marked on the label owing to your own sloppy application.

How high a rating?

The British Association of Dermatologists recommends sunscreens with an SPF of 30, while the NHS suggests a minimum of factor 15. Don’t forget you also need UVA protection – look for the UVA circle logo and/or four or five UVA stars to protect against UVA rays.

So is using sunscreen with an SPF of less than 15 pointless?

It’s not pointless, but unless you’re unusually diligent in applying your sunscreen you’re not going to get even the protection listed on the bottle. In fact, most people only get half or a third of the protection, so opting for an SPF of less than 15 means you should be reapplying constantly anyway.

Should someone else rub it on?

Yep, US research found people are most likely to miss the tops of their ears and the tops of the feet. Men are particularly likely to miss their scalps and the backs of their necks.

Do I only need it on at “peak times”?

You’re more prone to burning when the sun is directly overhead – from about 10 am-2pm – as UVB rays, which cause burning and some skin cancers, peak at midday. But UVA rays, which contribute to aging and some skin cancers are constant all day long.

Do I need sunscreen when it’s cloudy?

The sun laughs clouds’ puny attempts to protect us.

“A cloudy sky doesn’t protect you from the sun’s rays – 30-40% of UV will still penetrate through cloud cover,” says Stillman.

“If only half the sky is covered in clouds, 80% of UV will still shine through.”

Do I need to put on sunscreen if using a parasol?

Shading yourself with a sun umbrella is a smart move, especially during the hottest parts of the day, but if you're on a sandy beach you might still need some sunscreen.

“A sandy beach can actually increase reflected radiation by up to 17%,” says Stillman, “meaning that the sun’s rays may still be reaching you.” Translation: wear sunscreen.

Why is the scalp an issue?

Men who neglect the scalp have a high risk of developing solar keratosis and skin cancers. The top of the head is exposed to the most UV rays.

Does my skin “type” matter?

Yes, many sunscreens are greasy and unsuitable for oily or acne-prone skin, which require lighter formulations. People with olive or pigmented skin often think they don’t need sunscreen but they do – skin of colour is also sensitive to damage caused by UV and requires protection.

Can I use one from my last holiday?

Probably not, check expiry dates as sunscreens lose their potency over time. Keep sunscreen bottles out of the sun and in the fridge when not in use – a warm environment will lessen the effectiveness of the SPF.