You may feel protected after slathering on your SPF 45 at the beach this weekend, but a recent report cautions against trusting just any sunscreen. A new study looking at popular sunscreen products discovered that while most prevent sunburns, not all creams sufficiently protect us from the ultraviolet light that destroys skin cells, and causes tumours and lesions. The questionable ingredient is vitamin A—an anti-oxidant that slows skin aging. In their annual consumer report, researchers at the Environmental Working Group say that due to its photocarcinogenic properties, vitamin A and its derivatives may actually accelerate the cancer that sunscreen is used to prevent. The group also stated that only 39 of the 500 products they examined were considered safe and effective to use.