Expired sunscreen is not reliably protective and generally should not be used. The active ingredients that block or absorb UV rays break down over time, and once a sunscreen passes its expiration date, you have no way to know how much protection remains. The FDA requires sunscreens to maintain their original SPF for at least three years, but that clock starts ticking at manufacture, not when you open the bottle.
What Happens to Sunscreen After It Expires
Sunscreen is regulated as an over-the-counter drug in the United States, and the FDA requires manufacturers to run stability testing to confirm the product holds its labeled SPF for a minimum of three years. After that point, the active UV filters may have degraded enough that the SPF on the label no longer reflects reality. An SPF 50 product might perform like an SPF 20 or lower, but you’d have no way to measure that at home.
The type of filter matters. Chemical sunscreens, which absorb UV radiation using ingredients like avobenzone and oxybenzone, are more vulnerable to degradation. Avobenzone in particular is notoriously photounstable, meaning it breaks down when exposed to the very UV light it’s designed to block. Manufacturers add stabilizers to slow this process, but those stabilizers lose effectiveness over time too. Mineral sunscreens based on zinc oxide or titanium dioxide are inherently more stable since they sit on the skin’s surface and physically reflect UV rays, but the lotion or cream they’re suspended in can still separate and deteriorate, making application uneven.
A Concerning Breakdown Product
Beyond simple loss of SPF, some expired sunscreens may develop chemicals you don’t want on your skin. Products containing octocrylene, a common UV filter and stabilizer, can naturally degrade into benzophenone over time. Benzophenone is a suspected carcinogen that may also interfere with hormones and reproductive organs. A 2021 study published in Chemical Research in Toxicology tested 16 octocrylene-based sunscreen products purchased in France and the U.S., and every single one tested positive for benzophenone. The longer the product sits, the more benzophenone accumulates. This is one reason expired sunscreen isn’t just ineffective; it can be actively worse than wearing nothing, because you might skip reapplication while being exposed to both UV radiation and a problematic chemical.
Heat and Storage Speed Up Degradation
The three-year shelf life assumes reasonable storage conditions. If you’ve been keeping sunscreen in your car, a beach bag in direct sun, or a steamy bathroom, the active ingredients break down faster than the label suggests. Chemical filters like avobenzone and oxybenzone are especially sensitive to heat. A bottle that sat in a hot car through summer may lose meaningful protection well before its printed expiration date.
To get the most life out of your sunscreen, store it in a cool, dry place. At the beach or pool, wrap the bottle in a towel or keep it in the shade rather than leaving it baking in the sun. These small steps help preserve the formula’s stability for the full duration of its shelf life.
How to Tell if Your Sunscreen Has Gone Bad
Even if the expiration date hasn’t passed, your sunscreen can degrade prematurely. Watch for these signs:
- Separation or clumping: If the lotion has split into a watery layer and a thick layer, or has become grainy, the emulsion has broken down and the product won’t spread evenly or protect consistently.
- Color change: A yellowish or noticeably darker tint compared to when you bought it signals chemical changes in the formula.
- Off smell: A rancid or sour odor means the base ingredients (oils, emulsifiers) have degraded.
- Unusual skin feel: If the sunscreen no longer absorbs smoothly or causes stinging or irritation it didn’t before, the formula is compromised.
Any of these signs means you should replace the bottle, regardless of the printed date.
Finding the Expiration Date
Most sunscreens sold in the U.S. print an expiration date somewhere on the packaging, often on the bottom of the tube or the crimp seal. If there’s no expiration date, the FDA’s regulation means the manufacturer has tested it to remain stable for at least three years from the date of manufacture. In that case, write the purchase date on the bottle with a marker so you can track its age.
Many products also carry a small icon that looks like an open jar with a number inside, such as “12M” or “18M.” This is the Period After Opening (PAO) symbol, common on European and international products. It tells you how many months the product remains effective after you first open it. A sunscreen marked 12M should be used within 12 months of opening, even if the printed expiration date is further out. If you opened a bottle last summer and it’s been sitting in your cabinet since, the PAO may have already lapsed.
The Real Risk of Using It Anyway
The biggest danger of expired sunscreen isn’t a skin rash (though irritation is possible). It’s a false sense of security. If you apply an expired product, assume you’re protected, and spend hours in the sun without reapplying or seeking shade, you’re significantly more likely to burn. Repeated sunburns are a well-established risk factor for skin cancer, including melanoma.
If expired sunscreen is truly all you have and the alternative is no protection at all, applying it is better than bare skin. Some residual UV filtering likely remains, especially if the product is only slightly past its date and was stored properly. But treat it as a stopgap, not a solution. Combine it with protective clothing, a hat, shade, and limiting your time in direct sun. Replace it as soon as you can.