Cosmetics lab worker retesting product after out-of-specification (OOS) result

Jaclyn Bellomo

Senior Director of Cosmetic Science and Regulatory Affairs

OOS Results in Cosmetic: Prevention and Management

Jun 5, 2024

Producing safe cosmetics can be challenging. Many intentional and well-planned steps shape the process that leads to a safe and compliant cosmetic product. One of the most important steps in this process is testing. But what happens when a sample of your product results in an out-of-specification (OOS) result?

An OOS result happens when the test result of a sample does not meet the accepted established criteria. An OOS result indicates potential quality deviations or errors in the testing procedure.

It’s critical to maintain quality standards so your cosmetics are safe for consumer use and adhere to government regulations.

OOS results can cause delays in bringing your product to market, increasing costs for your company.

It’s best to prevent OOS results before they occur. However, if you do receive an OOS result, you should have a plan in place to uncover the root cause.

How to Prevent an OOS Result  

You can greatly reduce the likelihood of receiving an OOS result by following Good Manufacturing Practices (GMP). The most widely recognized standard for cosmetic GMPs is ISO 22716. The U.S. Food and Drug Administration (FDA) also established recommended guidance for GMPs for cosmetics based on ISO 22716.   

Here are some GMP guidelines that could help you prevent an OOS result:   

Maintain thorough records  

FDA recommends retaining records related to GMPs in paper or electronic format. Records should capture detailed information such as operations, procedures, deviations, instructions, raw material controls, and measures. Your records should be thorough so you can identify errors and apply corrective actions when needed.

Implement SOPs 

FDA also recommends establishing documented SOPs for manufacturing and control. SOPs should outline procedures for elements including formulations, processing, controls, packaging, and operating equipment.    

Conduct internal audits 

Internal audits are an effective way to assure you have put adequate measures into place. They’ll also assess whether staff are following protocol. You should conduct internal audits regularly or on demand.   

Buildings and facilities 

Manufacturing sites should be suitably designed and maintained in a clean and orderly manner. Controls should be in place to prevent errors, cross-contamination, filth, and pests.   


Processing, holding, transferring, and packaging equipment should be designed for the intended use and undergo regular sanitization and maintenance.    


All personnel should have adequate education, training, and/or experience to perform their assigned duties. They should also wear proper clothing and protective apparel, and maintain cleanliness.  

Raw materials 

FDA recommends raw materials be “identified, stored, examined, tested, inventoried, handled, and controlled to ensure they conform to appropriate standards and specifications.”

If a cosmetic contains water, it is at risk of microbial growth contamination. To prevent contamination, you should treat the water regularly and monitor for quality.

How to Manage an OOS Result

When your sample is determined OOS, an investigation is necessary to find the root cause. The OOS investigation should be timely, thorough, and fully documented.

Many errors could have led to the OOS result. Perhaps a sample was mishandled or improperly weighed. Maybe the root cause is due to a noncompliant raw material. Your GMP documentation will help you trace the sample throughout its journey, enabling you to indicate the point in the process that needs corrective action.

During an OOS Investigation, you should:

  • Report the product, formula, and batch(es)
  • Identify test(s) that were previously performed and passed
  • Assess for operational and evaluation errors in the previous test(s)
  • Conduct any required repeat tests. Report conclusions and measures

Repeat tests  

You may need to test a portion of your sample again to confirm your hypothesis was correct. After testing again and confirming you’ve found the root cause, enter the results. Then, note any measures you need to take to correct the problem and prevent it from happening again. 


OOS results can be a major setback for cosmetic companies if GMP documentation isn’t sufficient to provide adequate traceability. Although OOS investigations are an inconvenience, they are essential to assuring cosmetics are safe. When conducted properly, OOS investigations will not only help you correct previous errors. They will also help prevent those errors from recurring.    

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Jaclyn Bellomo

Senior Director of Cosmetic Science and Regulatory Affairs

A seasoned expert on the cosmetic industry, Jaclyn's deep understanding and insights on cosmetic regulations brought on with the passage of the Modernization of Cosmetics Regulation Act (MoCRA) are unmatched. Her experience and reputation throughout the global cosmetic industry helps companies worldwide meet the newly enacted FDA regulations under MoCRA.

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