{"id":19077,"date":"2026-06-16T01:40:56","date_gmt":"2026-06-15T18:40:56","guid":{"rendered":"https:\/\/www.tibdglobal.com\/product\/in-use-stability-testing\/"},"modified":"2026-10-06T13:28:32","modified_gmt":"2026-10-06T06:28:32","slug":"in-use-stability-testing","status":"publish","type":"product","link":"https:\/\/www.tibdglobal.com\/en\/product\/in-use-stability-testing\/","title":{"rendered":"In-Use Stability Testing Service: Simulating Real Consumer Use Conditions"},"content":{"rendered":"
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Many products in the health and beauty industry are designed for multi-dose use, meaning consumers open and close the packaging repeatedly throughout the product’s lifespan. Common examples include face cream in a jar, serum in a pump bottle, eye cream in a squeeze tube, and liquid medicine in a dropper bottle. Each time the product is opened and closed, it is exposed to moisture, air, microorganisms from the consumer’s fingers, and fluctuating temperatures, causing it to degrade faster than under standard storage conditions.<\/p>\r\n

In-Use Stability Testing is a study that simulates actual consumer use conditions to determine the Period After Opening (PAO) stated on the label and to confirm that the product remains safe and effective throughout the time a consumer is actively using it.<\/p>\r\n

TIBD’s service covers the design of In-Use Stability protocols that simulate consumer behavior in the ASEAN Zone IVb tropical-humid environment, analysis of physical, chemical, and microbiological changes over time, and interpretation of results to establish the PAO stated on the label, carried out in collaboration with VISBIO, an Independent Quality Assurance Verifier (IQAV).<\/p>\r\n[\/vc_column_text]\n\t\t

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<\/span>What Is In-Use Stability and the Importance of Period After Opening (PAO)<\/span><\/h4>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\n\t\t\t\n\t\t\t\n\t\t<\/div>\n\t\t\n\t\t[\/vc_column][\/vc_row][vc_row][vc_column width=”1\/2″][vc_column_text css=”” woodmart_inline=”no” text_larger=”no”]\r\n

In-Use Stability Testing is a study that evaluates the impact of repeated use on the characteristics of multi-dose products. It covers the effects of opening and closing packaging repeatedly, contact with the consumer’s fingers, and the temperature and humidity fluctuations that a product encounters in everyday use.<\/p>\r\n

The findings of this study are used to determine two key things. The first is the Period After Opening (PAO), represented by the open jar symbol with a number in months, such as 6M, 12M, or 24M, printed on cosmetic labels. The second is the storage conditions during use, such as “close tightly after each use,” “keep away from direct sunlight,” and “do not use fingers to scoop directly.”<\/p>\r\n[\/vc_column_text][\/vc_column][vc_column width=”1\/2″][vc_single_image image=”18907″ img_size=”full” alignment=”center” css=”” parallax_scroll=”no” woodmart_inline=”no”][\/vc_column][\/vc_row][vc_row][vc_column][vc_column_text css=”” woodmart_inline=”no” text_larger=”no”]\r\n

PAO is mandatory information required by cosmetic regulatory authorities in ASEAN under the ASEAN Cosmetic Directive and in the European Union under Cosmetic Regulation (EC) No 1223\/2009, specifically for multi-dose products with a shelf life exceeding 30 months. Brand owners without In-Use Stability data must estimate PAO without scientific evidence, which carries the risk of regulatory challenge and product recall if issues arise.<\/p>\r\n[\/vc_column_text][\/vc_column][\/vc_row][vc_row][vc_column]\n\t\t

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<\/span>Products That Require In-Use Stability Testing<\/span><\/h4>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\n\t\t\t\n\t\t\t\n\t\t<\/div>\n\t\t\n\t\t[vc_column_text css=”” woodmart_inline=”no” text_larger=”no”]\r\n

Any product designed to be used more than once or twice, where the packaging is repeatedly opened and closed, requires In-Use Stability Testing to establish a PAO and confirm safety throughout its period of use.<\/p>\r\n

Cosmetics in jars where consumers scoop product with their fingers represent the highest-risk category. This includes face cream, eye cream, body cream in jars, bar soap in a dish, and color cosmetics in compact form, because the consumer’s fingers introduce microorganisms directly into the product.<\/p>\r\n

Cosmetics in pump bottles and squeeze tubes, which have self-sealing mechanisms but are still exposed to air, include serum in pump bottles, lotion in pump bottles, cream in squeeze tubes, and lip balm in tubes. These carry moderate risk of moisture absorption and oxidative degradation.<\/p>\r\n

Products with dropper or spray systems, such as serum in dropper bottles, toner in spray bottles, and eye products in dropper vials, have good closure systems but are used frequently.<\/p>\r\n

Multi-dose liquid pharmaceuticals, including syrups, pediatric liquid medicines, eye drops, and nasal sprays, are required to undergo In-Use Stability Testing under pharmaceutical standards to confirm the stability of the active ingredient and the preservative system.<\/p>\r\n[\/vc_column_text][\/vc_column][\/vc_row][vc_row][vc_column]\n\t\t

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<\/span>Principles of Consumer Behavior Simulation<\/span><\/h4>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\n\t\t\t\n\t\t\t\n\t\t<\/div>\n\t\t\n\t\t[vc_column_text css=”” woodmart_inline=”no” text_larger=”no”]\r\n

A credible In-Use Stability study must simulate actual consumer use behavior as closely as possible. TIBD designs protocols that integrate consumer study data from the ASEAN market with international testing standards.<\/p>\r\n\r\n