German Cancer Aid warns against underestimating the spring sun. Using expired sunscreen can even be dangerous.
When sunscreen expires, the active ingredients that protect the skin from UV rays begin to lose their effectiveness. This process results in the sunscreen no longer being able to provide adequate protection against sunburn, skin damage or long-term skin problems such as premature aging and skin cancer. There is evidence that certain chemical ingredients in sunscreens, such as octocrylene, can decompose under certain conditions and form potentially dangerous compounds.