Difference Between Shelf life and PAO in EU Cosmetics: What You Need to Know
When selling cosmetic products in the European Union, understanding the difference between shelf life and Period After Opening (PAO) is crucial for regulatory compliance. This article explains these two concepts as defined by EU Cosmetic Regulation (EC) No 1223/2009, including when to use each, what documentation is required, and how to remain compliant.
What Is Shelf Life in Cosmetics? 
Shelf life refers to the period during which a cosmetic product, stored in its original unopened packaging, remains stable and safe to use. If a product has a shelf life of less than 30 months, it must be marked with a “best used before end of” date and the hourglass symbol (⌛) on the label.
- Applies to unopened products.
- Must be supported by stability testing (real-time or accelerated).
- Requires a justification statement explaining the scientific rationale.
- Declared using an expiry date.
What Is Period After Opening (PAO)? 
PAO indicates how long a product remains safe and effective after being opened for the first time. It is expressed in months and shown with the open jar symbol followed by a number (e.g., 12M for 12 months).
- Applies only to products with a shelf life of 30 months or more.
- Requires justification based on:
- Packaging type (e.g., airless pump vs. jar),
- Product formulation (e.g., oil-based vs. water-based),
- Results from a Preservative Efficacy Test (PET).
- Used when microbial contamination risk increases after opening.
When to Use Shelf Life vs. PAO
| Condition | Use Shelf Life | Use PAO |
|---|---|---|
| Product is stable < 30 months | ✔ | ✖ |
| Product is stable ≥ 30 months | ✖ | ✔ |
| Single-use or airtight packaging | ✔ | ✖ |
| High-risk formulation (e.g., open jar) | ✖ | ✔ |
Required Tests and Documentation
- Stability test report (for shelf life).
- Signed justification statement on company letterhead.
- PET results (for PAO if applicable).
- HRIPT (Human Repeat Insult Patch Test) results for leave-on products.
Common Questions About Shelf Life and PAO
Q1: Can I declare both shelf life and PAO? Only if justified. Typically, it’s one or the other based on whether the product is stable for 30 months.
Q2: What if I don’t have stability data? You cannot legally place the product on the EU market without proper documentation and justification.
Q3: Are there exceptions? Yes, for products in single-use packaging or those not exposed to contamination (e.g., aerosols), PAO may not be required.
In resume
Understanding and applying the correct shelf life or PAO is not just about consumer safety, it’s a legal obligation in the EU. Ensure your cosmetic products meet these requirements through proper testing, documentation, and labeling.
Need help compiling your Product Information File or conducting stability and PET tests? Contact our regulatory team today.
