With summer in full swing across the UK, many of us are reaching for sunscreen, yet persistent myths and conflicting information often leave people uncertain about its proper use. Dr. Rachel Neale, a skin cancer expert from the QIMR Berghofer Medical Research Institute, has been at the forefront of research into sun exposure, skin cancer, and vitamin D. Her work, including leading clinical trials and developing new guidelines on balancing sun exposure, offers clarity on how best to protect our skin.
Dr. Neale emphasises that sunscreen should be viewed as a final layer of defence, rather than the sole method of protection. Many mistakenly believe that applying sunscreen allows for prolonged sunbathing without risk. However, even the most effective sunscreen, applied perfectly, permits some ultraviolet (UV) radiation to reach the skin. Over extended periods, this cumulative exposure can lead to significant skin damage. Therefore, other protective measures, such as seeking shade, wearing hats, sunglasses, and protective clothing, particularly during the sunniest parts of the day, are crucial. Sunscreen should primarily cover areas not easily shielded, like hands and the neck.
The protective benefits of sunscreen are well-established. A significant, long-term study conducted in Nambour, Australia, tracked over 1,600 individuals from 1992. Participants were randomised to either apply sunscreen daily or continue their usual, often minimal, use. The findings revealed that those who used sunscreen daily were half as likely to develop melanoma in subsequent years. Furthermore, the study observed lower rates of skin ageing among the daily sunscreen group, with follow-up in 2014 even suggesting slightly fewer deaths from any cause in this cohort.
When selecting a sunscreen, Dr. Neale advises choosing one that you enjoy using. The most effective sunscreen is one that is consistently applied. While a high Sun Protection Factor (SPF) of 50+ is recommended for prolonged outdoor activities, an SPF 15 or 30 may suffice for shorter, intermittent exposures, especially if a higher SPF product feels less comfortable. Tinted sunscreens can offer comparable protection, but only if applied generously. As people often apply tinted products too thinly to avoid an overly coloured appearance, an effective strategy is to apply a thick layer of regular sunscreen first, followed by the tinted product.
Regarding the types of sunscreen, both chemical and inorganic (mineral) formulations primarily work by absorbing UV radiation. Chemical sunscreens, containing organic compounds like octocrylene and avobenzone, convert UV light into harmless heat. Mineral sunscreens, which contain zinc oxide or titanium dioxide, are often thought to reflect UV, but they also significantly absorb it. To achieve the SPF stated on the bottle, a generous application is necessary – approximately 2 milligrams per square centimetre of skin, equating to about seven teaspoons for an average adult’s full body. As applying this amount in one go can be challenging, Dr. Neale recommends applying two layers to ensure adequate coverage.