Sun creams, SPF and star ratings explained

Pick the right sun cream for your skinWe all know that sun cream is important and that the red-lobster look is never going to be on trend. Yet according to Macmillan Cancer Support more than 2,500 people die of skin cancer in the UK every year.

Too much sun has other adverse effects too. A particularly nasty one is actinic keratoses, which are growths of scaly skin found on your body – enough to have anyone reaching for the sun block. Not wearing sun cream can also make your skin age prematurely. To keep skin healthy, here’s how to ensure you choose the right sun cream and apply it correctly.

Sun creams explained: SPF and star rating

Sun cream works by blocking out the sun’s harmful ultraviolet light. The two types of ultraviolet light that are harmful are called UVA (ultraviolet A), which causes long-term skin damage and ages the skin, and UVB (ultraviolet B) rays, which burn our skin.

To protect skin from UVB rays the Cancer Council in Australia explains that we need to look out for the SPF (which stands for sun protection factor) because these numbers let you know how good the sun cream is at filtering out harmful UVB rays. The SPF numbers also indicates the strength of the sun cream.

In theory, multiplying how long it takes you to burn by the SPF factor should give you the length of time the cream will protect you. So if you usually burn after 15 minutes and put on a factor 20 sun screen, 15 x 20 = 300 minutes (5 hours) of burn-free sun time. Except that it doesn’t. Lower factors don’t filter out as many rays as higher ones, plus you’re more likely to burn when the sun’s at its hottest – between around 11am and 3pm. Added to this, people rarely put on (or reapply) the correct amount of sun cream to get the full effect.

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What SPF doesn’t cover is UVA rays. To find out how good the sun cream is at blocking out these, check out the star ratings on your sun cream bottle. The star ratings are on a scale, with zero being the lowest and five being the highest. The higher the amount of stars on the bottle the more you are protected from UVA rays. Most skin specialists advise that you choose a sun cream with at least four stars. The sun cream companies are awarded their stars after testing and some bigger brands, such as Garnier, conduct independent clinical studies to make sure their products are safe and effective.

Sun creams explained: What SPF do I need?

Skin experts classify skin into seven categories and divide these categories up into the following:

• Skin types one and two: people who have a pale, freckled complexion and burn easily
• Skin types three and four: people with slightly darker skin who tend to be European or Mediterranean and tan gradually
• Skin types five, six and seven:  people with dark skin, who are normally dark Asian or African and don’t typically burn

Professor Nicholas Lowe is a consultant dermatologist and he explains that 'People with skin types one and two should always use a minimum SPF of 30 with a four star UVA rating during the summer.’ For those with skin type three or four you should also choose an SPF 30 with four stars. For those people with dark skin and skin types five to seven you could go without sun cream, but if you don’t want too many wrinkles buy an SPF 15 with four stars.  If you are buying a sun cream for your children then you need to be aware that their skin is thinner and more prone to burning. Cancer Research UK advise that no matter what your child’s skin type you should always make sure they are covered up and have on a minimum of SPF 15.

Sun creams explained: How to apply sun cream

Although it sounds simple, applying your sun cream is something lots of people get wrong. You should put on sun cream 20 minutes before you head out in the sun. To make sure you are using enough, put sun cream along the length of two of your fingers and apply two fingers worth of cream to every part of your body listed below:

• Head, neck and face
• Upper back
• Lower back
• Upper leg
• Lower leg
• Each arm
• Chest
• Stomach

Reapply your sun cream at least twice a day and more so if you do activities that cause you to sweat, or if you swim. Despite wearing sun cream you should still avoid the sun when it’s at its hottest between 11am and 3pm.

Sun creams explained: Picking the appropriate sun cream for your location

If you are going on holiday you will probably need to change your sun cream and apply it more regularly. The closer you get to the equator the stronger the sun’s rays become, as well as the fact that you sweat more in the heat, thus sweating off the sun cream. Dermatologist Dr Anthony Young explains that: “If you're sunbathing in a swimming costume you should be getting through a standard bottle of sun-cream in a day”. If you are going skiing or hiking you need to understand that the higher you reach the stronger the UV radiation.   Also be aware that if you are swimming you need to reapply your sun cream; even if it’s waterproof.

Sun creams explained: What to do if you are sunburnt   

If you are burnt, stay out of the sun and use aftersun, which cools and moisturises skin. Professor Stanley Bleehen of the British Skin Foundation explains that when you are burnt you need to ‘rehydrate the skin to assist the repair process’ and aftersun does this. Look out for aftersun creams that contain Aloe Vera, which helps to soothe skin, or Vitamin E that helps to calm and smooth skin. You can also use calamine lotion to relieve some of the pain sunburn causes, or if mild, a simple moisturising lotion will help relieve symptoms.

If you don't manage to avoid burning, here are some remedies for treating sunburn.