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Period After Opening Testing

Period After Opening (PAO)

Period After Opening (PAO) refers to the period of time that a product remains suitable for use after its primary container has been opened.  

Period After Opening of Cosmetic Products

Difference Between PAO Date and Expiration Date

The PAO Date of a product is sometimes confused with the Expiration Date however the two are markedly different.  Expiration Dates are based upon stability studies conducted on a product in its “unopened” primary container, when maintained under the conditions of storage indicated on the product’s label.  PAO Dates are based upon stability studies conducted on a product in its “opened and then reclosed” primary container, when maintained under the conditions of storage indicated on the product’s label.  The fact that the primary container is opened and then reclosed is intended to allow for an assessment of the product that simulates (in some small way) consumer usage of the product.

Origin of PAO

PAO is a concept that originated within the European market and it applies only to cosmetic products having a shelf life of 30 months or greater.  It first appeared within Directive 2003/15/EC adopted in February of 2003 by the European Parliament and the Council amending previous regulations governing cosmetic products.  The requirement for indicating the PAO on labels of applicable cosmetic products sold within the EU took effect in March of 2005.  Cosmetic products having a shelf life of less than 30 months are not required to indicate a PAO on the label, although product owners have the option of doing so if they choose.

Is there a PAO requirement for cosmetic products sold in the USA?

There currently is no requirement for determining PAO of any cosmetic product sold within the USA.  That being said, if one chooses to include a PAO Date on a product label one can certainly do so, however one can expect that FDA may request to review the supporting evidence for that PAO during an inspection.

What is the required Protocol for determining PAO for the European market?

Although European regulations require the determination of PAO for applicable cosmetic products, the regulations fail to provide a specific protocol for achieving this goal.  As a result, owners of cosmetic products sold in Europe employ protocols of various types to arrive at the PAO for their products.  That said, the one basic requirement common to all is that the PAO assessment be conducted on a product in its primary container after it has been opened and then reclosed.

How can CPT assist with the determination of PAO for your Cosmetic products?

Our in-house experts are ready to offer guidance in developing protocols for determining the PAO of your cosmetic products in both a sensible and defensible manner.  Understanding the potential variables which influence a product’s suitability after the primary container has been opened is the first step.   Give us a call, even if you only wish to learn more about PAO.

Our Departments

Based on the individual needs of our clients, we offer a wide range of support across various departments. Since initial product testing can be fairly complex in terms of a high-quality, safe and trusted product, our clients typically explore the benefits of numerous departments and areas of expertise, including:

  • Clinical — Efficacy trials can be performed for safety, consumer in-use, and to support claims such as ‘dermatologist-tested’ and ‘ophthalmologist-tested.’
  • In-Vitro Toxicology — Our In-Vitro Toxicology department assists clients when they are looking to perform non-animal (animal-free) toxicology testing.
  • Microbiology — Microbial contamination and preservative efficacy testing are key to cosmetic and OTC drug products.
  • Photobiology — From SPF and Water-Resistant claims to Photoallergy and Phototoxicity studies, CPT℠ is the world leader in sunscreen testing.
  • Analytical — From raw materials, product batch release, and stability shelf-life testing to “free-of” and low-level detection claims, our analytical department ensures that all requirements are met based on industry standards.
  • Consulting – Our consulting staff can perform GMP and GLP audits of your facilities or vendors, help create SOPs, develop testing programs, etc.

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Please Note: CPT℠ only performs testing for companies. We do not perform product testing for the general public.