Does Sunscreen Expire? How Long SPF Really Lasts

You reach into the drawer or the beach bag and find a half-used bottle of SPF from a summer or two ago. Is it still fine to use, or should it go in the bin? The short answer is that sunscreen does expire, and using it past its best can leave you with weaker, less reliable protection. Here is how to tell where your bottle stands and how to keep it working for as long as possible.

Does sunscreen actually expire?

Yes. Sunscreen is a regulated cosmetic product with a finite shelf life, and its UV filters are active ingredients that gradually break down over time. As those filters degrade, the formula becomes less able to help protect your skin against UVA and UVB. In the UK, manufacturers are legally required to indicate how long a product stays at its best, so you are never left guessing entirely. The trick is knowing where to look and how to read the markings.

How do you read the expiry date and PAO symbol?

There are two markings worth checking on any sunscreen:

• A printed expiry or "best before" date. Products with a shelf life under 30 months usually carry a specific date, often near the crimp of the tube or stamped on the base of the bottle. Use the product before that date.
• The PAO (period-after-opening) symbol. This is a small open-jar icon with a number and the letter M inside it, such as 12M or 6M. It tells you how many months the product stays at its best once you have opened it. A 12M symbol means roughly twelve months from first opening.

If your sunscreen shows a 12M symbol but no printed date, it is worth noting on the bottle when you first opened it, so you have a reference point later.

How long does sunscreen last once opened versus unopened?

As a rough guide:

• Unopened and stored sensibly: most sunscreens keep until their printed expiry date, which is typically two to three years from manufacture.
• Once opened: follow the PAO symbol. Many facial and body sunscreens carry a 12M rating, though some sit at 6M or 9M.

Here is the practical catch for the UK: because our sunny spells are short, a bottle you open in June may still be sitting around the following summer, quietly past its 12-month window. If you use SPF daily all year round, which is the ideal, you will get through a bottle well within its life. If you only reach for it on holiday, you are far more likely to keep a product past its best.

Does heat and sun make sunscreen degrade faster?

It can, and this is where a lot of sunscreen quietly goes off before its printed date. UV filters and the emulsion that holds them together are sensitive to heat, direct sunlight and repeated temperature swings. The two worst places to store sunscreen are exactly where people tend to leave it:

• A hot car. A glovebox or door pocket can reach very high temperatures in summer, which can break down the formula prematurely.
• A beach bag in full sun. Hours baking on the sand, often with the cap not fully closed, is hard on any SPF.

If a bottle has spent a whole season cooking in the car, treat it with suspicion even if the date looks fine. The printed life assumes reasonable storage.

What are the signs sunscreen has gone off?

Trust your senses. A sunscreen that has degraded will usually tell you before the date does. Signs to look out for:

• Smell: an off, sour or unusually strong chemical odour compared with when it was new.
• Texture: it feels grainy, watery, clumpy or noticeably thicker or thinner than before.
• Separation: the oil and water phases have split and will not blend back together with a shake.
• Colour: yellowing, darkening or any visible change from the original shade.

Any of these is a reasonable cue to replace the bottle rather than risk patchy, unreliable cover.

Does expired sunscreen still work, and is it risky?

Expired sunscreen may still offer some protection, but you cannot rely on it to deliver the SPF and broad-spectrum performance printed on the label. As the filters break down, coverage becomes weaker and less even, so you could be getting far less protection than you think while assuming you are fully covered. That false sense of security is the real problem. Rather than gambling on a degraded bottle, it is far safer to replace it so you get dependable protection that helps reduce the risk of sunburn and premature ageing. When in doubt, throw it out.

How should you store sunscreen to make it last?

A few simple habits keep your SPF working to its full life:

• Store it somewhere cool, dry and out of direct sunlight, such as a bathroom cabinet or bedroom drawer rather than a sunny windowsill.
• Keep it out of hot cars and do not leave it baking in a beach bag; tuck it into a cool bag or under a towel on hot days.
• Close the cap firmly after each use to limit air and contamination.
• Note the date you opened it if the product only shows a PAO symbol.
• Buy a size you will realistically use up within its window, and use SPF generously and often, which naturally keeps your stock fresh.

If you are ready to replace a tired bottle, our best facial sunscreen UK buyer's guide walks through broad-spectrum options for everyday wear, and you can browse the full range in our sunscreen collection. For more on how SPF fits into daily protection, head back to the Sun Protection & SPF hub.

Sunscreen FAQs

How long does sunscreen last once opened?

Check the period-after-opening symbol, the small open-jar icon with a number and an M. Many sunscreens are rated 12M, meaning around twelve months from first opening, though some are 6M or 9M. After that window the UV filters may have weakened, so it is best to replace the product.

Can I use last year's sunscreen?

Possibly, if it is within its printed date and period-after-opening window, has been stored somewhere cool, and shows no change in smell, texture or colour. If it lived in a hot car or beach bag all summer, or looks or smells off, replace it rather than rely on weakened protection.

Where can I find the expiry date on sunscreen?

Look for a printed "best before" date near the crimp of the tube or on the base of the bottle, and for the open-jar PAO symbol showing months after opening, such as 12M. Products lasting under 30 months carry a specific date; longer-life ones rely on the PAO symbol.

What happens if you use expired sunscreen?

The filters degrade over time, so expired sunscreen may give weaker, less even and less reliable protection than the label states. You might think you are fully covered when you are not, which raises the risk of sunburn. For dependable broad-spectrum cover, use a product that is within its date.

Does sunscreen go off in heat?

Yes. Heat, direct sunlight and repeated temperature swings can break down UV filters faster than normal, so a bottle left in a hot car or a sun-baked beach bag can degrade before its printed date. Store sunscreen somewhere cool and dry, and treat any bottle that has overheated with caution.

How can I tell if my sunscreen has gone bad?

Use your senses. Watch for an off or sour smell, a grainy, watery or clumpy texture, oil and water that have separated and will not remix, or any yellowing or colour change. Any of these signs means the formula has degraded, so it is time to replace the bottle.