“You can use it a year later”: This mark on the tube tells you whether your sunscreen from last summer is still safe
You just found a tube of sunscreen at the bottom of your beach bag. It’s from last summer, it’s half full, and you’re not sure whether to throw it away. Good news: there are specific guidelines for determining whether your sunscreen is still safe to use, and one mark on the tube tells you almost everything.
The icon that changes everything on your tube of sunscreen
On every cosmetic package, a small symbol shaped like an open jar indicates the Use-By Date, often followed by “12M” or “18M.” Most sunscreen products are labeled “12M ”: this means that, once opened, the product must be used within one year. After this period, the UV filters degrade and the actual SPF drops.
So, if you opened the tube in June of last year, the theoretical expiration date is June 2026. However, the “best before” date applies only to unopened tubes. As long as this minimum shelf life has not expired, an unopened sunscreen is generally still usable.
In addition, storage plays a direct role. A product left in an overheated car or exposed to the sun deteriorates faster than a tube stored away from heat.
What the UFC-Que Choisir study says
To test these limits, UFC-Que Choisir monitored eight products over a 14-month period as they were subjected to alternating cycles of cold, intense heat, and artificial UV light. At the end of the test, six out of eight products remained stable.
“So you can use a cream that still looks normal a year later. However, using it for three summers in a row would probably be excessive. ” — UFC-Que Choisir
These reassuring results do, however, have a clear limitation. Formulas containingoctocrylene are not subject to this reassuring stability.
Octocrylene, the sunscreen ingredient that has experts concerned
Laurence Coiffard, a professor and researcher in cosmetic formulation at the University of Nantes, is sounding the alarm about this chemical filter. According to her, octocrylene “becomes carcinogenic when it breaks down over time” and “this degradation is completely invisible—consumers have no way of knowing it’s happening.”
Therefore, even a tube that appears to be intact can be problematic if its formula contains this ingredient. Simply check the INCI list on the back of the product to see if it’s included.
Furthermore, organic sunscreens with mineral filters were not included in the UFC-Que Choisir study. This calls for particular caution when using these products, given the lack of available data on their long-term stability.
- Check the open-jar symbol and the indicated shelf life (12M or 18M).
- Check the best-by date on unopened tubes.
- Check the list of ingredients for octocrylene.
- Check the texture: any separation, lumps, or phase separation is a warning sign.
- Smell the product: If it has a rancid or suspicious odor, throw it away immediately.
Texture, smell, color: three tests to try at home on your sunscreen
Once the expiration dates have been checked, the next step is to examine the product itself. UFC-Que Choisir recommends looking for “signs of deterioration.” A safe sunscreen retains a uniform texture: if oil separates from the cream or if lumps appear, the product should be discarded.
Smell is also a reliable indicator. “If the product smells rancid or has any other suspicious odor: throw it away!” warns the organization. There should be no hesitation when faced with this warning sign.
As for color, unusual yellowing or browning—especially in white formulations—indicates chemical degradation of the filters. In this case, the level of protection becomes unpredictable.
Why Inadequate Protection Poses a Real Risk to the Skin
Using sunscreen with a low SPF exposes your skin to far more UVA and UVB rays than you might think. The WHO emphasizes that repeated sunburns significantly increase the risk of melanoma.
Therefore, the best way to protect yourself is to check your tube before each season, rather than keeping it from one year to the next just to save money. A product that has sat unused through several summers without being checked should not be applied to the skin.
On the other hand, a tube that has been open for less than a year, has been stored properly, looks and smells normal, and does not contain octocrylene in its formula can certainly be safely reused this summer.
