What does SPF mean? Your suncare FAQs answered

Ask a Dermatologist: How Can You Protect Your Skin From The Sun?

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Ask a Dermatologist: How Can You Protect Your Skin From The Sun?

Our skincare experts reveal everything you need to know about protecting your skin from the sun.

From understanding the risks of UV exposure to knowing how often you should apply sunscreen, we asked skin experts Dr Hiva Fassihi and Dr Justine Hextall to answer an exhaustive list of your most pressing suncare questions.

What does SPF mean? Your suncare FAQs answered
What does SPF mean? Your suncare FAQs answered

What steps should I take to protect my skin from sun damage? 

“The most important step we can take to protect our skin is to actually avoid sun exposure when the sun is at its highest in the sky, and at its strongest,” says Dr Hiva Fassihi. “In the middle of the summer, this is usually between 11-2pm so if you do have to go out, cover up with clothing, hats, and glasses. You should also apply sunscreen 20 minutes before you go out, and then reapply it every couple of hours if you’re spending a prolonged period of time outdoors”.  


What’s the difference between UVA and UVB? Should we be blocking both types of rays and does regular sun cream do this? 

“UVB only penetrates the top layer of the skin but is associated with sunburn,” says Dr Justine Hextall. “UVA penetrates deeper to the dermis and is more associated with skin ageing as it damages the skin structure causing skin wrinkling and UV ageing. Both are now felt to be associated with the development of skin cancer. 

“This wave-length penetrates deep into the skin and studies have shown it stimulates an enzyme MMP-1 that breaks down collagen and elastin, our skin’s scaffolding which leads to sun ageing,” Dr Hextall continues. “It causes free radical damage and studies are looking at the implications of this for our skin. Unlike with UVB and UVA, you cannot block Infrared-A as it is too long a wavelength. A combination of anti-oxidants when applied to the skin can help to mitigate against this free radical damage. Increasingly as dermatologists, we are looking to protect skin against these longer wavelengths that we now believe contribute to sun-ageing”.


What does SPF mean and which factor should I be using? 

“The Sun Protection Factor or the SPF is the protection you have against Ultraviolet B,” says Dr Hiva Fassihi. “And the higher the SPF, the more protection you get. We don’t generally apply our sunscreen thickly enough to always achieve the maximum SPF, so I always recommend you go for a higher SPF so that you get the most amount of protection you can”.


How do I know which SPF factor to use?

“When choosing a sun cream, the rule of thumb is the higher the SPF, the better the protection from UVB,” says Dr Justine Hextall. “Factor 15 blocks 93% of the sun’s rays, whilst 97% are blocked by factor 50. Although a sun cream may block UVB and stop you burning, it may not block UVA which is often referred to as UV ageing, as these longer wavelengths penetrate deeper into the skin, damaging our collagen and causing loose wrinkly skin. It is now believed that UVA has a role in skin cancer too including melanoma development, so a broad spectrum sunscreen should protect against both UVA and UVB rays. It is important to note when measuring SPF, the trials put sun cream on the skin at 2mg per cm2”.


How often should I apply sunscreen?

“It’s really important to reapply your sunscreen as once is often not enough,” says Dr Fassihi. “Particularly if you’re on holiday and regularly swimming and towel drying. This makes it really important to reapply every couple of hours to make sure that your sun protection is adequate”.

UVA and UVB is also present in the winter months,” continues Dr Fassihi. “Particularly UVA which is present all year round. I recommend wearing sun protection on your face every day throughout the year to prevent the signs of ageing”.


Should you use a separate sunscreen on your face?

“I generally encourage people to use a separate sunscreen for their face,” says Dr Fassihi. “The facial skin is very sensitive and different in different people. Some people are prone to getting break-outs or spots and some have very dry skin, so you can really tailor your sunscreen dependant on your skin type”.


Is it enough to wear a moisturiser or a fake tan product with an added SPF in the sun? 

“SPF used in moisturisers is tested the same way as in sunscreens, so an SPF 15 moisturiser should provide an SPF of 15,” says Dr Hextall. “However, these formulas are less likely to be rub-resistant and water resistant, and most importantly are likely to be applied a lot more thinly than sunscreen. They therefore are unlikely to offer the same level of protection”.


Are there any communities of people most at risk in the sun? 

“I think everyone should be careful in the sun, however there are individuals who are at higher risk,” says Dr Hiva Fassihi. “Those with very fair skin and blue eyes easily burn and I think those individuals should be particularly careful. There are also people who spend a lot of time outdoors and they should take extra care”.


Do people with darker skin have to be as careful in the sun? Are the effects of the sun the same for all skin tones? 

“Our skin has cells called melanocytes that produce melanin,” explains Dr Justine Hextall, FRCP Consultant Dermatologist. “The darker the skin, the more melanin these cells produce. Melanin helps protect the skin against the effects of the sun such as skin cancers and premature ageing. In African-American skin, melanin provides a sun protection factor (SPF) approximately equivalent to 13.4, compared to 3.4 in white skin. This discrepancy illustrates why skin cancer is more prevalent in Caucasian people. Whilst the risk of skin cancer is less in darker skin, the ageing effects of the sun are still seen e.g. wrinkles and sunspots so sun cream is still recommended. If exposed to strong sunlight for a prolonged period of time all skin types should be protected with sun cream”.


What sunscreen range do you recommend?

“Generally I’d suggest that the sunscreen range you use is one that has a high factor, provides good protection and is broad-spectrum - so it covers the UVA and UVB range,” says Dr Fassihi. “La Roche-Posay and the Anthelios range are generally designed for people with sensitive skin.”


What makes La Roche-Posay different from other brands when it comes to suncare

“La Roche-Posay works closely with dermatologists to develop and design their sunscreens,” explains Dr Fassihi. “They have a huge range of products for everyone from children to adults. La Roche-Posay are also involved with sun awareness and skin cancer campaigns so they really help the public to be aware of the dangers of sun exposure”.