How do you determine how long your cosmetic product will remain safe for use, continue to meet the intended physical, chemical and microbiological quality standards, look and smell as intended and continue to function as it should? In other words, how do you determine the shelf life of the product? You have to perform a stability test.

A stability testing can be done:

• under accelerated conditions (i.e., at elevated temperatures),
• in real time (e.g., if you want to claim a one-year shelf life, you monitor the product for one year) or
• freeze thaw (i.e.; temperature cycling between freezing and room temperature).

and it should test the stability of the product in various possible storage conditions – different temperatures, humidity and light conditions; it should consider the product transport and use conditions. Therefore, because the products are different and their storage, transport and usage conditions are different, there is no standard stability test protocol. Stability tests can be adapted to each individual product and to the specific needs of the clients.

Even though there is no standard stability test, each stability test should monitor:

• The physical and chemical stability
• The microbiological stability of the product
• Packaging stability and its compatibility with the product

The evaluated parameters monitored to evaluate the stability of the product vary, but generally include those such as colour, odour, appearance, pH, viscosity, density, weight and microbiology.

The conclusion of the stability test should mention whether the product is stable, what the shelf life of the product is, if the product can or should put either the date of minimum durability or the period after opening on the label and if any specific storage conditions should be written in order to achieve that shelf life.

Every cosmetic product needs to undergo stability testing and the stability of the products should be re-evaluated whenever the formula, packaging, production method or the equipment etc. is changed.

Luamed has the proper equipment, knowledge and experience to advise on the appropriate stability test protocol for your products and to carry out the test.