Stability Test

Cosmetic products must maintain their formulation and efficacy from manufacturing to the end-user. During this period, the product is exposed to environmental factors such as heat, light, and humidity. Stability tests are conducted to assess whether the product retains its physical, chemical, and microbiological properties under these conditions.

What is a stability test?

A stability test is a laboratory examination in which a cosmetic product is stored for a specified period under defined temperature and humidity conditions to determine its perishability and shelf life. At the end of the test, the following product properties are evaluated:

• pH value: TS 518, TS 5270, TS 4811, TS 9676
• Packaging changes (breakage, cracking, sealing)
• Sensory changes (odor, color, appearance): Regulation (EC) No. 1223/2009, TS 12439
• Viscosity change
• Weight change
• Determination of microbial load

evaluated.

Why conduct stability testing?

• To determine shelf life
• To assess packaging suitability for the product
• To prevent consumer complaints and product recalls
• To underscore the product's 'reliability' in the marketing process
• To comply with regulatory requirements (EC 1223/2009)

How is the Test Performed?

Stability tests are typically conducted under the following conditions:

• Real-time conditions (e.g., 25 °C / 60% RH)
• Accelerated conditions (e.g., 40 °C / 75% RH)
• Freeze-thaw cycles
• Photostability

Test duration varies by product type; accelerated tests involve observations over a 3-month period, while real-time tests span 6-12 months.

Which products should be tested?

• Creams, Lotions
• Shampoos and shower gels
• Lipstick, foundation, mascara
• Eye Area Products
• Baby products and sunscreens