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9 common sunscreen mistakes to avoid

Why you're probably not using enough, and the everyday medications that can affect skin sun sensitivity

Sunscreen is an essential part of staying safe in the sun, and with temperatures soaring it's worth refreshing your skin protection know-how.

The risk of sunburn are real and well-documented. According to Cancer Research UK, 86% of UK melanoma skin cancer cases are preventable.

In the sometimes lacklustre British summer, it can be tempting to make the most of any warm spells (and good sunscreen practice may be a bit rusty) but it's really important to protect yourself and loved ones from the power of the sun.

We've rounded up the common sunscreen mistakes people make, as well as popular misconceptions that can contribute to getting caught out - and how to avoid them.

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1. Not using enough sunscreen - and not reapplying frequently

Most people don't apply enough sunscreen to achieve the SPF specified on the packaging, the World Health Organization (WHO) says.

A 2020 Cancer Research UK survey found that just 37% of people take their sunscreen with them to apply throughout the day, and similar numbers don't bother with sunscreen when in the garden or exercising outside.

The WHO recommends around one teaspoon-sized dollop per limb/body part, so seven if you're doing the whole lot.

Sunscreen also needs to be re-applied regularly, especially after swimming and other sporting activities.

Don't think clouds mean you don't need sunscreen either, you can still burn even on cloudier days.

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2. Relying too much on once-a-day or water-resistant claims (without reading the small print)

When Which? tested once-a-day sunscreens in 2016, we found that the SPF provided fell by 74% after six to eight hours.

What's more, our testing also found that salt water, chlorinated water and fast-running water made water-resistant sunscreens less effective.

The British Skin Foundation warns that swimming, sweating, towelling down or clothes rubbing against your skin can remove sunscreen.

Claims on once-a-day or water-resistant products are often based on very specific test criteria (found in small print on the back of the bottle). Based on our previous research we have concerns they don't stand up to real world conditions and may give users a false sense of security.

So, even if you opt for one of these products, don't skimp on the reapplying, especially after vigorous activity - and read the caveats.

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3. Using old or out-of-date sunscreen

Sun cream usually lasts for one to two years after opening - although check the back of the bottle for specifics. Beyond this it may not protect you as expected as the active ingredients can degrade, so it's best not to rely on an old bottle you've dug out of the cupboard.

To find the expiry date, look for an illustration of a circular pot with an open lid on the back of the bottle. This tells you the use-by date by the number of months (see picture above). So 12M means it's OK for 12 months after opening, 24M means 24 months.

Leaving your sun cream lying around in the sun is also a bad idea. It's best to keep out of direct sunlight and in a cool, dark and dry place. This may not always be practical when you're out in the sun, but you can pop it in a cool bag or with your other belongings so it's not too exposed. 

Looking for a sensitive or chemical-free sunscreen? Make sure you read our mineral sunscreen investigation first

4. Not putting sunscreen on until you're already in the sun

Whilst it's not always possible to predict when you'll need it, sunscreen should ideally be applied 20-30 minutes before sun exposure (and before insect repellent, moisturiser and make-up).

This is especially the case for chemical sunscreens (also known as organic or synthetic sunscreens - and the most common high street type). These work by being absorbed into the skin to absorb UV rays, and need to sink in for optimal protection. It's worth also applying mineral (physical) sun blocker in advance too.

5. Misunderstanding how SPF numbers work

The SPF (sun protection factor) is an indication of the amount of UVB rays that are filtered out by a product, with higher SPF products filtering out more than lower ones.

But it's best not to think of the SPF number as indicating how much longer you can stay out in the sun without burning as it isn't quite that simple.

If your skin burns easily, it's best to pick a higher SPF. The NHS recommends at least SPF 30 for everyone, regardless of skin type.

SPF numbers aren't a linear scale either. For example, SPF 30 filters out around 97% of UVB rays, SPF 50 around 98% and SPF 100 about 99%. So don't let an ultra-high SPF lull you into a false sense of security. Frequent reapplication is still important, especially if you have very sun-sensitive skin.

SPF, UVA, UVB: sun cream explained and how to buy the best - find out more in our sunscreen buying guide

6. Missing common sunburn hotspots

Pay particular attention to the most exposed parts of your body, such as the ears, nose, forehead (including hairline) and back of the neck. These are often missed during application, and sun cream gets quickly rubbed away as they tend to be areas that have higher friction or are prone to sweating.

Think about areas of delicate skin that don't often see the sun too, such as the tops of your feet and the back of your knees.

Don't forget to protect your scalp (for example, on bald patches and partings) and consider a hat, especially if you have very short, reduced or thinning hair.

Lips are another neglected area - use photoprotective lip balm, as are the eyelids.

If you're out in the heat of the sun, don't rely solely on sunscreen. A broad-brimmed hat or bucket hat are good options to reduce UV exposure to delicate areas. Baseball caps won't protect your neck and ears.

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7. Not realising that some meds make you more sun sensitive

It's worth knowing that some common medications can make your skin more sensitive to the sun.

Professor Claire Anderson, president of the Royal Pharmaceutical Society, says: 'Quite a few medicines can make you more photosensitive, including common drugs such as antibiotics, oral contraceptives and antidepressants - but not everyone who takes them will have a reaction.'

It's worth checking about any new meds, and if you notice an unusual reaction from sun exposure and have started a new medication recently, check with your pharmacist.

Reduce your risk of side effects such as a rash or sunburn-like symptoms by staying out of direct sunlight, using a high-factor sunscreen and covering up with long sleeves, trousers and a hat. 

A 'sensitive-skin' sun cream may also help to reduce the risk of a reaction.

Medications that can cause sun sensitivity

  • Irregular heartbeat medication amiodarone
  • Some antibiotics, including trimethoprim (used mainly for urinary tract infections) and doxycycline (a broad-spectrum antibiotic) 
  • Tricyclic antidepressants, including amitriptyline and climipramine
  • Type 2 diabetes drug sulphonylurea
  • Acne drug isotretinoin (trade name Roaccutane)
  • Coal tar preparations and steroid creams used for skin conditions such as psoriasis
  • Diuretics furosemide and thiazides
  • Antimalarial drugs including quinine

8. Relying on SPF make-up

Even if your make-up claims to offer sun protection, you’d typically need to apply several times the normal amount of it to get even close to the level of protection stated on the packaging.

Not only that but you're less likely to reapply make-up regularly enough, which means that using make-up with SPF is not a substitute for using sunscreen.

Professor Brian Diffey, emeritus professor of photobiology at Newcastle University, says: 'Apply sunscreen first as it needs to bind to the outer layer of the skin to be effective.'

If you put make-up on first, the sunscreen might not bind properly and could compromise its ability to protect you. 

9. Thinking that having darker skin protects you

A 2021 review article published in the journal Skin Health & Disease found that the risk of skin cancer in those with darker skin colours is underestimated, and people of colour are less likely to use sunscreen, are less likely to report sunburn and tend to seek medical help for skin cancers later.

Misconceptions about the protective effects of having a tan still abound too. The bottom line is that sun protection is important for everyone.

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How to stay safe in the sun

Start your sun protection right with a product you can rely on. Our sunscreen tests reveal that some products don't offer the level of protection claimed on the bottle. See our sun cream reviews for the cheap high street sun creams that do the job and the ones to avoid.

Don't neglect other important sun safety elements too - sunglasses protect the eyes from damaging UVB and UVA light, which can lead to conditions including cataracts and retinal damage such as macular degeneration.

Look for the CE, UV400 or British Standard (BS) mark when buying sunglasses. Sunglasses sold under BS 2724 will have a 'shade number' and the higher the number, the better the UV protection.

Finally, remember that UVA rays can penetrate through glass. So if you're in the car a lot on sunny days, or like to sit by a sunny window, take precautions.

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