"If the sunscreen smells bad or different from when it was new, throw it away. A change in smell can indicate that some of the ingredients in the cream have broken down or that there is bacterial growth in the product."
Annonse
Ellen Bruzell is a senior researcher at the Nordic Institute of Dental Materials. She recommends buying new sunscreen, just to be on the safe side.
Still, if the choice is between expired sunscreen and no sunscreen at all, she is clear about which option is better:
"It's better to use the expired one if it still smells normal and looks the same. But keep in mind that it may no longer have the same SPF. You should apply it a little more often and a little more generously. And remember to buy a new one."
SPF stands for sun protection factor.
The symbol many people wonder about
"There is no single legally required, universal standard for the shelf life of sun care products," managing director Lin Grieg Teigland of the Norwegian Cosmetics Association writes in an email to Science Norway.
Among other things, the association works to ensure that products on the Norwegian market are safe to use.
According to Teigland, shelf-life labels are based on stability testing. In other words, how well the product keeps over time.
The PAO symbol may be marked with more or less than 12 months.(Photo: Anders Moen Kaste)
This can involve bacterial growth, chemistry, and consistency under different storage conditions. There are requirements for these tests from the industry organisation Cosmetics Europe, which the industry follows, Teigland explains.
"The result is displayed on the packaging either as a use by date or a PAO symbol," writes Teigland.
The PAO symbol is an open jar and a number of months.
How long the product lasts under normal conditions
PAO indicates shelf life after opening. Many sunscreens and other cosmetic products are labelled with 12 months.
"It reflects the realistic conditions the product is exposed to during use – including heat, UV radiation, and repeated contact with hands or even beach sand," writes Teigland.
Annonse
"The PAO period represents the amount of time the product is expected to maintain both safety and effectiveness under normal storage conditions," she adds.
So how can you make sunscreen last as long as possible? Some people may think storing it in the fridge is the best solution.
"Apply it more often and a little more generously," is the researcher’s advice if you have forgotten to replace your old sunscreen. And it may be wise to buy a new one at the next opportunity, just to be on the safe side.(Photo: Anders Moen Kaste)
Keep it dry, not cold – and avoid extreme heat
A fridge is neither necessary nor generally recommended unless it says so on the packaging, according to Teigland.
"The most important thing is to store the product in a dry place and protect it from extreme heat and direct sunlight," she writes.
High temperatures and lots of sunlight can break down the product more quickly. This may change its properties and, most importantly, reduce its effectiveness.
PAO is a guideline. You should still make your own assessment. Has the sunscreen changed consistency, smell, or colour? These are clear signs that the product should be thrown away. This applies even if the PAO period has not expired, Teigland writes.
Can reduce UV protection
But how much does old sunscreen actually deteriorate? Does it simply become less effective, or can it become harmful?
The main risk is reduced UV protection, according to Teigland. In other words, you may become more vulnerable to sun damage.
"A product that has been stored correctly is not expected to lose its UV protection over time," writes Teigland.
She adds that modern sunscreen products are specifically designed to resist the breakdown of UV filters caused by light exposure.
