Sun bathing could be an even more dangerous hobby than has previously been thought, as new research indicates that sunscreen lotions might not effectively protect against skin cancer.

Professor Roy Sanders and colleagues — from the research charity Raft, based at the Mount Vernon hospital in London, UK — exposed skin that was removed from consenting patients to ultraviolet A (UVA) light at levels similar to those found in sunlight. They then compared the effects of applying three different brands of high-factor sunscreen lotion. Although the sunscreen prevented the skin from burning — attributed to another component of sunlight, UVB — the UVA could still penetrate the skin, leading to release of free radicals, which can cause DNA damage and lead to the formation of malignant melanoma.

Roy Sanders said that “This is a problem because if people are using these creams on the supposition that they do offer protection then they might be putting themselves at higher risk of skin cancer” (BBC News Online, 29 September 2003). The sun protection factor (SPF) of sun lotion refers only to protection from UVB, so using sunscreen might actually be harmful, as it encourages people to stay in the sun for longer.

The sunscreen manufacturers Boots have fought back though, as they claim that their products are important for sun protection, as “staying out of the sunshine completely is not an option most people care for” (The Independent, 29 September 2003).