As a heatwave with highs of 37C sweeps the UK, anyone applying sun cream is being urged to check a three-digit code on the bottle to ensure it still offers protection. The open-jar symbol on the back of sun cream bottles contains a code, such as '12M' or '18M', indicating how many months the product remains effective after opening. Using sun cream beyond this period means it will no longer provide the required level of protection.
Heatwave and UV risk
The Met Office forecasts another prolonged spell of dry and sunny weather, with temperatures steadily climbing before peaking on Thursday. An amber warning for extreme heat will be in force from 9am until midnight on Thursday, covering parts of southern and eastern England, the Midlands, and Yorkshire and the Humber. Very high temperatures could lead to adverse health effects.
Being out in the sun increases exposure to UV radiation, which can damage the skin and eyes. UV rays are typically strongest between 10am and 4pm, but exposure can still occur on cloudy days, making sun protection essential.
What to look for on the bottle
The NHS recommends using a sun cream with a sun protection factor (SPF) of at least 30 to protect against ultraviolet B (UVB) radiation, and with at least four-star ultraviolet A (UVA) protection. Bottles should show a star rating of up to five stars, with the letters 'UVA' inside a circle, a European marking meaning UVA protection is at least a third of the SPF value and meets EU recommendations.
Benenden Health explains: “To know when suncream expires, all you need to do is look out for the symbol that looks like an open jar on the sunscreen bottle. This has a number inside that tells you how long the product should be used after it has been opened. For example, if you see '12M' in the open jar, then the sun cream should be used within 12 months of cracking it open. After that time, the sun cream becomes ineffective, no matter how high the sun protection factor is. As such, try to remember when you last opened it and, if you know you used it last year, it’s time to buy a fresh one.”
Expiry and shelf life
Most sun creams have a shelf life of around three years, but once opened, they should be used within the timeframe on the symbol, usually 12 months. Susanna Daniels, CEO of charity Melanoma Focus, said: “In the UK, on sun lotion bottles you’ll see an SPF - you’re looking for anything above SPF 30 - and there’ll be a star-rating usually on the back. You’re looking for a four or five-star rating, which equates to your UVA protection. There’s also a picture of a bottle being opened, and it might have ’12M’ on it - that indicates how long the sun lotion will last before it expires. 12M means it will expire after 12 months of opening the sunscreen. Anything that’s kept in light or heats up, might not last as long as that.”
