Does Sunscreen Expire? Shelf Life, the Three-Year Rule, and the PAO Symbol

Dig through your bathroom drawer and you’ll probably find a sunscreen from a trip two summers ago, half used, with no obvious date on it. Is it still doing anything? Sunscreen expiration is real, and it matters more here than with the rest of your skincare, because a weak sunscreen doesn’t just underperform quietly, it leaves your skin exposed while you believe you’re covered. So let’s settle how long a bottle actually lasts, how to read the date or the little open-jar symbol on a Korean bottle, and how to tell when it’s time to toss it.

TL;DR: In the US, sunscreen is regulated as a drug, so it has to carry an expiration date unless it’s been shown to stay stable for at least three years. No date on the bottle? The FDA says treat it as expired three years after you bought it. Many imported Korean sunscreens skip the US-style date and show a small open-jar symbol instead, like 12M, which means use it within 12 months of opening. If it’s separated, changed color, or smells off, don’t use it. Expired sunscreen may not protect you, so when in doubt, throw it out.

Does sunscreen expire? Yes, here’s the short answer

Yes. Sunscreen loses effectiveness over time, which is exactly why US law treats it like a medicine with a shelf life rather than like a regular lotion. A sealed bottle generally lasts up to three years. Once it’s past its printed date, or it’s three years old with no date at all, it’s time to replace it. The reason it’s held to a stricter standard than your moisturizer comes down to one fact: in the United States, sunscreens are regulated as drugs ^[1].

Why sunscreen expiration is real, not marketing

Here’s the rule in plain terms. The FDA requires all nonprescription drugs to carry an expiration date, unless the manufacturer’s stability testing has shown the product will stay stable for at least three years ^[1]. So a bottle either prints a date, or the maker has proven it keeps working for three-plus years and is allowed to skip printing one. Either way, a real clock is ticking.

This is where it helps to know the difference between a cosmetic and a drug. A plain cosmetic, like a moisturizer or a lip balm, faces no such requirement: there are no US laws that require cosmetics to carry expiration dates at all ^[2]. Sunscreen is different because its job is an active drug function, blocking UV, so it must be tested for stability and carry a date ^[2]. The date isn’t a marketing suggestion. It’s the point at which the brand can no longer promise the SPF on the label.

No expiration date on the bottle? The three-year rule

This is the part that trips people up, because plenty of sunscreens genuinely have no printed date. The FDA’s guidance is simple: a sunscreen with no expiration date should be considered expired three years after purchase ^[1]. Put concretely, the agency recommends you:

1. Don’t use a sunscreen that’s past its printed expiration date, if it has one.
2. Don’t use a sunscreen with no date that you didn’t buy within the last three years.
3. If you don’t know how old your sunscreen is, discard it ^[1].

The easiest habit that saves you the guessing game: write the month you opened it on the bottle with a marker. Ten seconds now, no detective work in two summers.

Reading a Korean label: the PAO open-jar symbol

If you order Korean sunscreens, you’ve probably noticed they often don’t carry a US-style expiration date, because they were labeled for markets that mark things differently. Instead of hunting for a date that may not be there, look for two things.

First, a manufacturing or use-by date, sometimes printed as MFD (made on) or EXP (use by), and sometimes in a day-month-year order that looks unfamiliar at first. Second, and this is the one most people miss, the PAO symbol. PAO stands for Period After Opening. It’s a small drawing of an open jar with a number next to it, like 12M or 6M. Under EU cosmetics rules, products that stay good for more than 30 months show this open-jar symbol with a number of months instead of a best-before date ^[3]. So 12M means once you open it, use it within 12 months.

The catch worth understanding: the PAO number counts from the day you open the bottle, while the three-year rule counts from when you bought or made it. Keep it simple. An unopened bottle is governed by its date or its three-year window. Once it’s open, that little open-jar number becomes your clock, and you go by whichever date arrives first.

How to tell your sunscreen has gone off

Dates are the rule, but your senses are the backup, and they matter because heat and time change a formula in ways you can actually notice. Over time, sunscreens start to break down, and the FDA describes the tells plainly: changes in color and texture, and a product that starts to smell ^[2]. In a sunscreen that usually looks like:

• Separation: a watery or oily layer sitting on top, or a texture that’s gone grainy, clumpy, or oddly runny.
• A color shift: white or clear turning yellow or dull.
• An off smell: sharp, rancid, or just different from how it smelled new.

Any one of these means replace it, even if the date still looks fine. When the bottle and the calendar disagree, trust the bottle. And don’t talk yourself into rubbing in a separated sunscreen on the assumption that the SPF survived, because you can’t tell by looking whether the UV filters still work at full strength. The safe move is a fresh bottle.

One thing ages a sunscreen faster than the calendar, and that’s heat. A bottle that spent the summer in a hot car or the bottom of a beach bag can break down before its date ever arrives. Storing and traveling with sunscreen is a bigger subject that deserves its own guide, so we’ll keep it short here. The FDA’s own rule of thumb is printed right on the label, which is required to say: protect the product in this container from excessive heat and direct sun ^[1].

So what should you actually do

Sunscreen expiration comes down to a quick check you can run the next time you pick up a questionable bottle. For the date math (steps 1 to 3), our free sunscreen expiry calculator does it for you:

1. Look for a printed expiration date. If there is one, it wins, full stop.
2. No date? Count three years from when you bought it, and replace it after that.
3. Opened, with a 12M-style open-jar symbol? Use it within that many months of opening.
4. Separated, discolored, or smells off? Replace it no matter what the date says.
5. No clue how old it is? The FDA’s answer is to discard it ^[1].

None of this is a reason to skip sunscreen or ration an old one to make it last. A fresh, in-date bottle is cheap next to the skin protection it buys. And honestly, if you’re using enough sunscreen to begin with (about a teaspoon for the face, the dose our how much sunscreen guide breaks down with sources), reapplied through the day, most bottles get used up long before sunscreen expiration is even a question. If you find yours lasting a suspiciously long time, that’s usually a sign you’re applying too little. Our complete guide covers how the filters and SPF actually work, and if the bottle in question is your beach-and-travel one, the water-resistant sunscreen guide covers that side.

FAQ

Does sunscreen expire?

Yes. In the US, sunscreen is regulated as a drug, so it carries an expiration date unless it’s been proven stable for at least three years. Past that date, or three years after purchase if there’s no date, it may not protect you properly and should be replaced.

How long does sunscreen last after opening?

A good guide is the open-jar PAO symbol on the bottle, a number like 12M meaning 12 months after opening. If there’s no symbol, use an unopened bottle within its expiration date or within three years of purchase, and replace any bottle that has separated, changed color, or started to smell.

Can I use expired sunscreen?

It’s not worth the risk. The FDA says to discard expired sunscreen because it may not be safe and effective anymore, and you can’t tell by looking whether the UV filters still work. If it’s past its date or you don’t know how old it is, replace it.

My Korean sunscreen has no expiration date, just a 12M symbol. What does that mean?

That open-jar symbol is the Period After Opening. 12M means use the product within 12 months of opening it. Many sunscreens made for outside the US show this instead of a US-style expiration date. Note the date you open it, and go by whichever comes first, the PAO window or three years from purchase.

Sources

Primary and authoritative:
[1] Sunscreen: How to Help Protect Your Skin from the Sun, U.S. FDA (sunscreens regulated as drugs; expiration date required unless stable three-plus years; undated sunscreen expired three years after purchase; discard if age unknown; label must warn to protect from excessive heat and direct sun): link
[2] Shelf Life and Expiration Dating of Cosmetics, U.S. FDA (no US requirement for cosmetics to carry expiration dates; drugs must be tested for stability and carry printed dates; degradation shows as changes in color, texture, and smell): link
[3] Regulation (EC) No 1223/2009, Article 19, European Union (products lasting more than 30 months show the open-jar Period After Opening symbol with the number of months, in place of a best-before date): link