Sun & Skin
Does sunscreen expire? Shelf life, dates and when to toss it
How to find the date on your bottle
Look in three places: a printed expiry date (usually stamped on the crimp or bottom), a batch code (some brands let you decode the production date online), or the PAO symbol — a small open jar with “12M” inside, meaning 12 months after opening. No date anywhere? US rules assume three years of full potency from manufacture, so a fair rule of thumb is: bought more than two summers ago and already opened — replace it.
What actually happens when sunscreen expires
Chemical UV filters slowly break down — avobenzone, the workhorse UVA filter, is the most fragile and degrades faster with heat and light. The lotion may look fine while quietly delivering a fraction of the labelled SPF. Mineral filters (zinc oxide, titanium dioxide) are more stable chemically, but the formula around them separates over time — and a separated sunscreen spreads unevenly, which in practice means patchy protection and surprise burn lines.
Five signs a bottle is done
| Sign | What it means |
|---|---|
| Watery layer on top, shake doesn’t fix it | Emulsion has broken — uneven coverage |
| Gritty or clumpy texture | Filters or thickeners have crystallised |
| Color shift (yellowing) | Oxidation — actives degrading |
| Sour or “off” smell | Preservatives failing; possible microbial growth |
| Spent a summer in the car | Heat-aged — treat the date as void |
Storage decides everything
The three-year clock assumes room temperature. A glovebox at 60 °C or a beach bag in direct sun ages sunscreen in weeks, not years. Keep the bottle in the shade, in a cooler bag with the drinks, or wrapped in a towel — and store the reserve tube at home in a cupboard, not in the bathroom’s heat and steam. Unopened and stored cool, sunscreen genuinely keeps to its printed date.
One more habit beats every expiry question: if you’re using sunscreen the way dermatologists intend — a shot-glass amount per application, reapplied every two hours — a bottle empties in days, not years. Expired sunscreen is usually a symptom of under-use. Check today’s UV index before you head out, and let the number tell you how much you’ll need.
Frequently asked questions
Can I use sunscreen that expired last year?
It is better than nothing in a pinch, but do not rely on it: the labelled SPF is no longer guaranteed, and degraded UVA filters fail invisibly. For a beach day or high UV index, buy a fresh bottle.
Does unopened sunscreen expire?
Yes, but slowly. Unopened and stored cool and dark, it keeps full potency to the printed date — in the US at least three years from manufacture. Heat is what breaks the rule.
How long does sunscreen last once opened?
Most labels carry a 12M open-jar symbol: 12 months after opening. Air, fingers and temperature swings start the clock; write the opening month on the bottle to keep track.
What happens if I use expired sunscreen?
You get less protection than the label promises — sometimes far less — so you burn faster than expected. Expired formulas can also separate or irritate sensitive skin.