The Importance of Cosmetic Stability Testing

There are many “mom and pop” cosmetic companies out there that are making great, unique products in their kitchens. Unfortunately, these products are not always properly tested, and some are even unsafe to use.

The purpose of stability testing cosmetic products is to ensure that a new or modified product meets the intended physical, chemical and microbiological quality standards as well as functionality and aesthetics when stored under appropriate conditions.

A good cosmetic manufacturer or development laboratory will always perform the necessary testing on the products that they create and produce.

In general, stability tests can be conducted in real time or under accelerated conditions and should address the stability of a product under appropriate conditions of storage, transport and use.

Physical/Chemical Stability Tests

These describe approaches to predicting how well cosmetics will resist common stresses such as temperature extremes and light. Typically, manufacturers determine whether to perform such specialized testing based on the vulnerabilities of the particular cosmetic product and its anticipated shipping, storage display and use conditions.

Common testing procedures include temperature variation, freeze/thaw cycles and UV light application. For all of these tests, the lab will monitor the color, odor / fragrance, viscosity and pH value to ensure no changes take place.

Microbiological Stability Tests

Microbial contaminants usually come from two different origins: during production and filling, and during the use of the cosmetic by the consumer. From the moment the cosmetic unit is opened by the consumer, a permanent microbial contamination of the cosmetic is introduced caused by contact with the consumers’ hands and body.

Microbial preservation of cosmetics is important to ensure the microbial safety of cosmetics for the consumer, maintain the quality of the product, and confirm hygienic and high-quality handling. Although only a small number of cases of microbial infections of the consumer have been reported, microbial contamination of cosmetic products may spoil them or seriously reduce the intended quality.

Therefore, it is necessary to carry out routine microbiological analysis of each batch of the finished product coming on the market.

Packaging Stability Tests

Packaging can directly affect finished product stability because of interactions which can occur between the product, the package, and the external environment. For example, product constituents may be absorbed into the container or may chemically react with the container. In addition, the container may not fully protect the product from the adverse effects of atmospheric oxygen and/or water vapor, or volatile product constituents (e.g. fragrances) may evaporate through the container.

The Bottom Line

If you are developing a product line, you want to ensure the safety of the product for your consumer and should therefore choose a cosmetic development laboratory that has strict guidelines for the testing of your products.