Stability Testing of Cosmetic Products in the US

Currently there are no specific requirements for conducting stability testing or assigning expiration dates to cosmetic products that are distributed in the US.  That said, conducting stability testing on cosmetic products makes good business sense so that the effectiveness of a product’s preservative system and the maintaining of a product’s quality attributes may be confirmed over time, thereby reducing the possibility of consumer complaints, adverse events, product recalls and loss of market share.  Additionally, the changing regulatory environment for the US Cosmetic Industry may soon require stability testing for each cosmetic product and the establishing of expiration dating as you will see later in this article.        

What is a Stability Study and what is its purpose?

A stability study is a program of testing that is designed to provide evidence of how the quality of a product varies with time under the influence of a variety of environmental factors such as temperature, humidity and light.  Stability testing enables the establishing of shelf life (expiration date) when packaged in the primary container system in which the product is distributed.  Stability testing is also used for establishing recommended storage conditions for the product.

What Types of Stability Studies are Commonly Conducted for US Cosmetic Products?

In the absence of FDA-sanctioned protocols for conducting cosmetic stability testing, product owners have enjoyed the freedom of employing strategies that they believe are most appropriate for their product(s).  Although a wide range of temperature and humidity have been utilized for stability testing within the Cosmetic Industry, the basic environmental conditions established by FDA for US drug products are the most commonly used: Real Time (25^o C/60% Relative Humidity), Accelerated (40^o C/75% Relative Humidity), and Freeze/Thaw (Cycled between -20^oC and +25^o C).

Does MoCRA require the Stability Testing of US Cosmetic Products?

The Modernization of Cosmetics Regulation Act of 2022 (commonly known by its acronym “MoCRA”) was signed into law on December 23, 2022.  Its intent is to modernize Federal regulatory oversight of cosmetic and personal care products and create a comprehensive and uniform national framework for their regulation.  Click on this link to learn more about MoCRA.

Among the many elements now required by MoCRA is a fully documented substantiation of the safety of each cosmetic product.  Although FDA has historically held cosmetic product owners responsible for the safety of their products, MoCRA has significantly elevated the safety standard against which cosmetic products will now be held.  FDA’s basic definition of a “safe” cosmetic product is one that is not adulterated and not misbranded.  According to FDA, an adulterated product is one which contains poisons or other filthy, putrid, decomposing or otherwise deleterious substances; or which has become contaminated and rendered injurious to health.  In requiring a formal substantiation of the safety of each cosmetic product, MoCRA now requires a science-based and formalized ‘proof’ of the safety of cosmetic products including testing for skin irritation and the presence of harmful ‘contaminants’ such as objectionable microorganisms, elemental impurities (heavy metals) and allergens.

Although not specifically stating that stability testing is required to be conducted on cosmetic products, how else is one to substantiate the safety of a cosmetic through the period of time that it is available for purchase and use, unless stability testing is conducted?  This would include Antimicrobial Effectiveness Testing not only of a representative “fresh” batch of each cosmetic product but also on a batch which has been “aged” in its commercial packaging.  A cosmetic product cannot be considered “safe” from microbiological contamination unless its preservative system has been shown to be effective throughout the life of the product.  Additionally, FDA has long held the belief that a “physical” change to a product reflects a “chemical” change.  A cosmetic product which breaks down over time resulting in a physical separation of its component ingredients could, depending upon the chemical nature of those ingredients, cause skin irritation.  This is an especially serious matter for cosmetic products that are applied in the area of the eyes or mucous membranes.  Thus it would appear that although not expressly required by MoCRA, FDA is expecting that stability testing will be conducted in support of demonstrating the safety of each cosmetic product.

Will the Soon-To-Be-Published GMP for the US Cosmetic Industry Require Stability Testing?

Under MoCRA, Congress has mandated that FDA publish a Notice of Proposed Rulemaking for a Good Manufacturing Practice (GMP) regulation for the US Cosmetic Industry no later than 2 years after the enactment date of MoCRA.  This means that FDA is required to unveil its new Cosmetic GMP before December 23, 2024.  Although no one will know for sure until it is published, many believe that the new Cosmetic GMP will require establishing an expiration date through stability testing prior to the launch of each cosmetic product.  It is also believed that FDA will provide guidance as to how cosmetic stability studies should be conducted with regard to standard environmental conditions, test points, and study duration.

Period After Opening (PAO) Stability

PAO is a type of stability study that is conducted to determine the period of time that a product remains suitable for use, after its primary container system has been opened.  There currently is no requirement for the determination of PAO for any product distributed within the US, however the European Union (EU) requires PAO determination for cosmetic products having an expiration date of 30 months or greater.  Although not required in the US, some manufacturers have started to implement the practice of determining PAO for products which they distribute within the US, possibly in response to the interests of savvy consumers who are aware of EU policy. 

How can CPT Assist in the Stability Testing of your Cosmetic Products?   

For over thirty years, CPT has successfully conducted thousands of stability studies for cosmetic and personal care products, drug products and dietary supplements.  Our team of experts within CPT’s Analytical Chemistry, Microbiology, and Stability Management Departments can guide you through the entire stability process, starting with protocol development, selection of testing methods and continuing right through the interpretation of test results.

We can also assist in the conducting of safety substantiations for each of your cosmetic products as now required by MoCRA, employing our knowledge of stability testing and its importance in demonstrating product safety. 

Why not give us a call today?  MoCRA product safety requirements are already in place and the Cosmetic GMP will be published in less than two years.  Now is the time to start planning the stability testing of your Cosmetic products.