Do you open your bathroom cabinet and find creams, serums, and makeup products that have been sitting there for years? Cosmetic products, just like food, have a shelf life — and using expired products can pose serious risks to your skin health. Here is everything you need to know.
What Is the PAO Symbol?
The open jar icon you see on packaging, along with the number printed on it, indicates the PAO (Period After Opening) — meaning the safe period of use after the product has been opened. For example, "12M" means the product can be used safely for 12 months after opening.
The PAO symbol applies from the moment the product is first opened — not from the purchase date, but from the day you first removed the lid. For this reason, many experts recommend writing the date you first opened the product on its packaging.
Common PAO Durations
| Product Type | Average PAO Duration |
|---|---|
| Sunscreen | 6–12 months |
| Eye creams | 6 months |
| Serums (vitamin C, etc.) | 3–6 months |
| Moisturisers | 12 months |
| Liquid foundation | 12 months |
| Mascara | 3–6 months |
| Lipsticks | 12–18 months |
| Powder products | 24 months |
| Perfumes | 24–36 months |
The Difference Between Expiry Date and PAO
The PAO and the expiry date are different concepts. The expiry date shows how long an unopened product can last. The PAO, on the other hand, indicates the safe usage period after the product has been opened.
Under European regulations, products with a shelf life shorter than 30 months must display an expiry date. For products with a shelf life longer than 30 months, the PAO symbol is used instead of an expiry date. Current 2026 regulations encourage manufacturers to include both types of information on packaging.
Risks of Using Expired Products
Using expired cosmetic products can lead to a number of problems:
Microbiological contamination: Once the preservative system loses its effectiveness, bacteria, yeast, and mould can begin to grow. This is especially concerning for products used around the eye area, where contamination can cause infection. Using expired mascara significantly increases the risk of conjunctivitis.
Active ingredient degradation: Active ingredients such as retinol, vitamin C, and AHA/BHA acids break down over time and lose their efficacy. An oxidised vitamin C serum not only becomes ineffective — it can also cause skin irritation.
Formula breakdown: Oil-water emulsions can separate over time. Changes in colour, scent, and texture are clear signs that a product has spoiled.
Allergic reactions and irritation: Degraded components can form new chemical compounds, triggering unexpected allergic reactions.
Proper Storage Conditions
Follow these guidelines to maximise the shelf life of your products:
- Keep products away from direct sunlight. UV rays rapidly break down many active ingredients.
- Humid and warm environments such as bathrooms are not ideal for many products. Choose a cool, dry location instead.
- For jar-type packaging, use a spatula rather than your fingers. This minimises the risk of bacterial contamination.
- Close lids tightly after each use. Air exposure accelerates oxidation.
- Storing sensitive active ingredients such as vitamin C serums and retinol in the refrigerator can extend their shelf life.
When Should You Discard a Product?
In addition to the PAO period expiring, stop using a product if you notice any of the following: a change in colour, an altered smell, a change in texture, or phase separation. If you experience unexpected redness, itching, or irritation on your skin, discontinue use of the product immediately.
For professional guidance on skin health and cosmetic product selection, please contact our clinic. We are here to help you build an up-to-date and effective skincare protocol tailored to your skin type. Please contact us for pricing information on our consultations and skin analysis services.
This article is for informational purposes only. Please consult a qualified physician for treatment decisions.