As spring weather brings intermittent sunshine across the UK, experts are urging the public to check a specific symbol on sunscreen bottles before use. The Period After Opening (PAO) symbol, typically found on the back of the bottle, indicates how long a product remains effective after being opened. Ignoring it could leave skin vulnerable to sunburn and increase the risk of skin cancer.
The symbol resembles a small open jar and includes a number followed by the letter 'M', such as '8M' or '12M', representing months of safe use after opening. Consumer specialists at Which? advise marking the date of first opening on the bottle with a permanent marker to track its usability. Using expired sunscreen may not be dangerous, but its UV-protective ingredients can degrade, leading to inadequate protection.
Board-certified dermatologist Rutledge Forney told the Skin Cancer Foundation: 'Sunscreen does lose its effectiveness over time, and you need to respect the expiration date. I have seen numerous sunburns on patients who realised too late that their sunscreen was expired.' If no expiration date is visible, he recommends noting the purchase date and discarding the product after three years.
The NHS warns that sunburn remains a threat even on cloudy days, making proper sunscreen application essential. Adults should use approximately six to eight tablespoons to cover their entire body. For further guidance on sun safety, visit the NHS website.
