Cosmetic product labeling not only informs consumers about ingredients, usage instructions, or precautions, but also about the product’s durability. Two key concepts in this regard are the expiry date and the PAO (Period After Opening). Both provide essential information to ensure product safety and efficacy throughout its usable life.
This article delves into the regulations governing these aspects, the differences between the two concepts, and recommendations for determining and properly labeling the PAO in cosmetics.
What is PAO?
The PAO indicates the minimum period after opening during which a cosmetic product can be safely used. It applies to products whose total shelf life (unopened) exceeds 30 months.
This concept was introduced in Directive 2003/15/EC, amending Directive 76/768/EEC on cosmetic products, and later incorporated into Regulation (EC) No 1223/2009.
The PAO is represented by the open jar symbol followed by a number and the letter “M” (for months), such as “12M” or “24M”.
👉 This symbol must appear on both the primary packaging (tube, jar, etc.) and the secondary packaging (box), unless the product is exempt from PAO labeling.
When is PAO Required?
PAO labeling is mandatory when:
- The product’s shelf life exceeds 30 months.
- The container allows contact with air or the user’s fingers.
PAO is not required in the following cases:
- Products with a shelf life of 30 months or less (must display expiry date instead).
- Single-dose or one-time use products.
- Sealed or pressurized containers that prevent air entry (e.g., aerosols).
- Anhydrous products or those with high alcohol content (≥30%), which are less prone to microbial growth.
How is PAO Determined?
PAO determination must be based on stability studies that assess:
- Microbiological stability after opening.
- Formula compatibility with packaging.
- Frequency and method of intended use (application area, shared use, etc.).
- Storage conditions (temperature, humidity, sunlight exposure).
- The formulator’s experience with similar products.
👉 It is recommended to express PAO in multiples of 3 months (e.g., 6M, 9M, 12M, 18M, 24M…) according to COLIPA guidelines.
PAO Guidelines by Product Type
| Product Type | Recommended PAO |
| Occlusive cosmetics (jars, creams) | 6 to 12 months |
| Eye contour products | 6 to 9 months |
| Eye makeup | 6 to 12 months |
| Lip makeup | 12 to 24 months |
| Roll-on deodorants or emulsions | 12 months |
| Baby hygiene products | 3 to 12 months |
| Body hygiene | 12 to 18 months |
| Sunscreens | According to stability studies |
Differences Between PAO and Expiry Date
| Feature | PAO | Expiry Date |
| Applies to… | Products >30 months | Products ≤30 months |
| How it appears | Open jar symbol + “M” | Text: “Best used before…” |
| Related to… | Use after opening | Unopened product |
| Affected by consumer use? | Yes | No |
| Assessed via… | Post-opening stability studies | Accelerated or real-time studies |
Additional Regulatory Aspects
- The date format must comply with ISO 8601, e.g., “YYYY-MM-DD”.
- The PAO does not replace the expiry date when the latter is mandatory.
- Responsibility for defining PAO lies with the product responsible person.
Compliance and Safety Tips
- Incorporate PAO evaluation into overall stability testing.
- Consider microbial risk depending on the packaging type.
- Always indicate PAO for products likely to be used over time.
- Avoid generic estimations without analytical support.
Best Practices for Consumers
- Read labels carefully.
- Do not use opened cosmetics past their PAO.
- Avoid storing products in humid or warm environments.
- Use clean applicators and avoid sharing personal products.
SHAPYPRO and PAO Evaluation
At SHAPYPRO, we offer comprehensive cosmetic stability and safety testing services, including:
- Accelerated and real-time stability testing.
- Scientifically justified PAO estimation.
- Microbiological evaluation and packaging compatibility testing.
- Technical reports for cosmetic product information files.
We have extensive experience with Regulation (EC) No 1223/2009 and support manufacturers and responsible persons throughout the cosmetic product lifecycle.
If you need advice contact us.
Conclusion
PAO and expiry date labeling are key tools for ensuring consumer safety and legal compliance of cosmetic products. Their proper determination and inclusion on labels reflect the manufacturer’s commitment to quality and transparency.
SHAPYPRO positions itself as a strategic partner to support companies in PAO evaluation and product stability, ensuring compliance with European standards.
This is an ignorant, politically-correct defense of an absurd, meaningless labeling requirement.
Degradation kinetic start the day the product was made, not when the package was opened. However by PAO, a product made last year and opened by the consumer today will carry the same PAO as a product made yesterday and opened today. Clearly the stability status of these two products is different.
Worse, some manufacturer label with brief periods to cover instability. For example – a PAO of six months is meaningless as there’s no assurance the product ,the stability of which dated from the day of making, reaches and is opened by the consumer in six months – almost guaranteeing expiration in use.
Thank you for your comment and for raising an important point that is often subject to technical discussion within the field of cosmetic product safety and stability.
First, it is correct that physicochemical and microbiological degradation processes begin from the moment a product is manufactured. This principle is well established in the scientific literature on stability of cosmetic and pharmaceutical products. However, the concept of shelf life in cosmetics is not based solely on absolute degradation kinetics, but rather on the evaluation of stability under reasonably foreseeable storage conditions, including the product in its unopened container.
In this context, European legislation—specifically the Regulation (EC) No 1223/2009—clearly distinguishes between two different concepts that should not be conflated:
On one hand, the Minimum Durability Date (MDD) applies to products with a shelf life of less than 30 months and indicates the period during which the product, when stored appropriately, continues to fulfill its intended function and remains safe prior to opening. This parameter does account for degradation from the date of manufacture.
On the other hand, the Period After Opening (PAO) applies to products with a minimum durability greater than 30 months and represents the time during which the product remains safe after first use. This concept does not replace closed-container stability, but rather complements it by addressing a different scenario: exposure to microbial contamination, oxygen, light, and variability in consumer use.
From a technical standpoint, PAO determination is supported by specific studies, including:
These studies are designed to simulate real-use conditions that are not covered by standard closed-package stability testing.
Regarding your observation about products manufactured at different times carrying the same PAO, it is important to note that the regulatory framework addresses this variability through additional mechanisms:
The mandatory inclusion of a batch number, which ensures full traceability of the product and its manufacturing date. This allows manufacturers and authorities to assess any issues related to the time elapsed before opening.
Furthermore, Good Manufacturing Practices, as defined in ISO 22716, require manufacturers to establish and control the overall product shelf life, including storage and distribution conditions, ensuring that the product remains compliant at the time it is placed on the market.
With respect to short PAO values (e.g., six months), these should not be interpreted as an attempt to compensate for instability, but rather as a risk management measure for the post-opening phase, particularly relevant for formulations with:
Low preservative content, high water activity, or usage patterns that increase the likelihood of contamination.
In such cases, the PAO reflects the product’s evolution after opening, not its prior stability. Regulatory requirements ensure that the product is safe at the time of placing on the market, regardless of the time elapsed since manufacture, provided that the MDD and storage conditions are respected.
Finally, it is important to emphasize that the combined system of MDD, PAO, and batch traceability is not arbitrary. It is based on a risk-based approach that differentiates between unopened and in-use product conditions, aligned with the guidance of the Scientific Committee on Consumer Safety (SCCS) and internationally recognized best practices.
In conclusion, while PAO does not represent the full degradation history of a product, it serves a specific and necessary role within the cosmetic regulatory framework, complementing other measures designed to ensure product quality and safety throughout its lifecycle.
Please do not hesitate to contact us should you wish to explore this topic further.